The adherence and merging of cell membranes, intracellular membranes, or artificial membranes to each other or to viruses, parasites, or interstitial particles through a variety of chemical and physical processes.
Proteins, usually glycoproteins, found in the viral envelopes of a variety of viruses. They promote cell membrane fusion and thereby may function in the uptake of the virus by cells.
Fusion of somatic cells in vitro or in vivo, which results in somatic cell hybridization.
A superfamily of small proteins which are involved in the MEMBRANE FUSION events, intracellular protein trafficking and secretory processes. They share a homologous SNARE motif. The SNARE proteins are divided into subfamilies: QA-SNARES; QB-SNARES; QC-SNARES; and R-SNARES. The formation of a SNARE complex (composed of one each of the four different types SNARE domains (Qa, Qb, Qc, and R)) mediates MEMBRANE FUSION. Following membrane fusion SNARE complexes are dissociated by the NSFs (N-ETHYLMALEIMIDE-SENSITIVE FACTORS), in conjunction with SOLUBLE NSF ATTACHMENT PROTEIN, i.e., SNAPs (no relation to SNAP 25.)
Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.
Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.
A specific HLA-B surface antigen subtype. Members of this subtype contain alpha chains that are encoded by the HLA-B*40 allele family.
Time period from 1501 through 1600 of the common era.
Traditional Arabic methods used in medicine in the ARAB WORLD.
A glycosyl-phosphatidyl-inositol (GPI) - anchored membrane protein found on the thick ascending limb of the LOOP OF HENLE. The cleaved form of the protein is found abundantly in URINE.
Eating an excess amount of food in a short period of time, as seen in the disorder of BULIMIA NERVOSA. It is caused by an abnormal craving for food, or insatiable hunger also known as "ox hunger".
Conversations with an individual or individuals held in order to obtain information about their background and other personal biographical data, their attitudes and opinions, etc. It includes school admission or job interviews.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
The motion of phospholipid molecules within the lipid bilayer, dependent on the classes of phospholipids present, their fatty acid composition and degree of unsaturation of the acyl chains, the cholesterol concentration, and temperature.
The study of those aspects of energy and matter in terms of elementary principles and laws. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.
Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.
A fluorescent compound that emits light only in specific configurations in certain lipid media. It is used as a tool in the study of membrane lipids.
The study of the characteristics, behavior, and internal structures of the atomic nucleus and its interactions with other nuclei. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Time period from 1901 through 2000 of the common era.
Time period from 1801 through 1900 of the common era.
Time period from 2001 through 2100 of the common era.
The biological science concerned with the life-supporting properties, functions, and processes of living organisms or their parts.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
The rate dynamics in chemical or physical systems.
The chemical reactions involved in the production and utilization of various forms of energy in cells.
Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.
A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)

Membrane fusion: structure snared at last. (1/3607)

The structure of the core of the neuronal 'SNARE complex', involved in neurotransmitter release, has been determined recently. Its topological similarity to viral fusion proteins suggests how the SNARE complex might facilitate membrane fusion.  (+info)

Biophysical characterization of the structure of the amino-terminal region of gp41 of HIV-1. Implications on viral fusion mechanism. (2/3607)

A peptide of 51 amino acids corresponding to the NH2-terminal region (5-55) of the glycoprotein gp41 of human immunodeficiency virus type 1 was synthesized to study its conformation and assembly. Nuclear magnetic resonance experiments indicated the sequence NH2-terminal to the leucine zipper-like domain of gp41 was induced into helix in the micellar solution, in agreement with circular dichroism data. Light scattering experiment showed that the peptide molecules self-assembled in water into trimeric structure on average. That the peptide molecules oligomerize in aqueous solution was supported by gel filtration and diffusion coefficient experiments. Molecular dynamics simulation based on the NMR data revealed a flexible region adjacent to the hydrophobic NH2 terminus of gp41. The biological significance of the present findings on the conformational flexibility and the propensity of oligomerization of the peptide may be envisioned by a proposed model for the interaction of gp41 with membranes during fusion process.  (+info)

SNARE interactions are not selective. Implications for membrane fusion specificity. (3/3607)

The SNARE hypothesis proposes that membrane trafficking specificity is mediated by preferential high affinity interactions between particular v (vesicle membrane)- and t (target membrane)-SNARE combinations. The specificity of interactions among a diverse set of SNAREs, however, is unknown. We have tested the SNARE hypothesis by analyzing potential SNARE complexes between five proteins of the vesicle-associated membrane protein (VAMP) family, three members of the synaptosome-associated protein-25 (SNAP-25) family and three members of the syntaxin family. All of the 21 combinations of SNAREs tested formed stable complexes. Sixteen were resistant to SDS denaturation, and most complexes thermally denatured between 70 and 90 degreesC. These results suggest that the specificity of membrane fusion is not encoded by the interactions between SNAREs.  (+info)

Treatment of mouse oocytes with PI-PLC releases 70-kDa (pI 5) and 35- to 45-kDa (pI 5.5) protein clusters from the egg surface and inhibits sperm-oolemma binding and fusion. (4/3607)

The effect of phosphatidyinositol-specific phospholipase C (PI-PLC) on mouse sperm-egg interaction was investigated in this study to determine if glycosyl-phosphatidylinositol (GPI)-anchored proteins are involved in mammalian fertilization. When both sperm and zona-intact oocytes were pretreated with a highly purified preparation of PI-PLC and coincubated, there was no significant effect on sperm-zona pellucida binding; however, fertilization was reduced from 59.6% (control group) to 2.8% (treatment group). A similar reduction in fertilization rates was found when zona-intact oocytes were treated with PI-PLC and washed prior to incubation with untreated sperm. The effect of PI-PLC on sperm binding and fusion with zona-free oocytes was then investigated. Treatment of sperm with PI-PLC had no significant effect on sperm-egg binding or fusion. However, treatment of eggs with PI-PLC significantly reduced sperm-egg binding and fusion from 6.2 bound and 2.1 fused sperm per egg in the control group to 2.1 bound and 0.02 fused sperm per egg in the treatment group. This decrease in sperm-egg binding and fusion depended on the dose of PI-PLC employed, with a maximal inhibitory effect on binding and fusion at 5 and 1 U/ml, respectively. PI-PLC-treated oocytes could be artificially activated by calcium ionophore, demonstrating that the oocytes were functionally viable following treatment. Furthermore, treatment of oocytes with PI-PLC did not reduce the immunoreactivity of the non-GPI-anchored egg surface integrin, alpha6beta1. Taken together, these observations support the hypothesis that PI-PLC affects fertilization by specifically releasing GPI-anchored proteins from the oolemma. In order to identify the oolemmal GPI-anchored proteins involved in fertilization, egg surface proteins were labeled with sulfo-NHS biotin, treated with PI-PLC, and analyzed by two-dimensional gel electrophoresis followed by avidin blotting. A prominent high-molecular-weight protein cluster (approximately 70 kDa, pI 5) and a lower molecular weight (approximately 35-45 kDa, pI 5.5) protein cluster were released from the oolemmal surface as a result of PI-PLC treatment. It is likely that these GPI-anchored egg surface proteins are required for sperm-egg binding and fusion.  (+info)

Genetic interactions between KAR7/SEC71, KAR8/JEM1, KAR5, and KAR2 during nuclear fusion in Saccharomyces cerevisiae. (5/3607)

During mating of Saccharomyces cerevisiae, two nuclei fuse to produce a single diploid nucleus. Two genes, KAR7 and KAR8, were previously identified by mutations that cause defects in nuclear membrane fusion. KAR7 is allelic to SEC71, a gene involved in protein translocation into the endoplasmic reticulum. Two other translocation mutants, sec63-1 and sec72Delta, also exhibited moderate karyogamy defects. Membranes from kar7/sec71Delta and sec72Delta, but not sec63-1, exhibited reduced membrane fusion in vitro, but only at elevated temperatures. Genetic interactions between kar7 and kar5 mutations were suggestive of protein-protein interactions. Moreover, in sec71 mutants, Kar5p was absent from the SPB and was not detected by Western blot or immunoprecipitation of pulse-labeled protein. KAR8 is allelic to JEMI, encoding an endoplasmic reticulum resident DnaJ protein required for nuclear fusion. Overexpression of KAR8/JEM1 (but not SEC63) strongly suppressed the mating defect of kar2-1, suggesting that Kar2p interacts with Kar8/Jem1p for nuclear fusion. Electron microscopy analysis of kar8 mutant zygotes revealed a nuclear fusion defect different from kar2, kar5, and kar7/sec71 mutants. Analysis of double mutants suggested that Kar5p acts before Kar8/Jem1p. We propose the existence of a nuclear envelope fusion chaperone complex in which Kar2p, Kar5p, and Kar8/Jem1p are key components and Sec71p and Sec72p play auxiliary roles.  (+info)

Rat liver GTP-binding proteins mediate changes in mitochondrial membrane potential and organelle fusion. (6/3607)

The variety of mitochondrial morphology in healthy and diseased cells can be explained by regulated mitochondrial fusion. Previously, a mitochondrial outer membrane fraction containing fusogenic, aluminum fluoride (AlF4)-sensitive GTP-binding proteins (mtg) was separated from rat liver (J. D. Cortese, Exp. Cell Res. 240: 122-133, 1998). Quantitative confocal microscopy now reveals that mtg transiently increases mitochondrial membrane potential (DeltaPsi) when added to permeabilized rat hepatocytes (15%), rat fibroblasts (19%), and rabbit myocytes (10%). This large mtg-induced DeltaPsi increment is blocked by fusogenic GTPase-specific modulators such as guanosine 5'-O-(3-thiotriphosphate), excess GTP (>100 microM), and AlF4, suggesting a linkage between DeltaPsi and mitochondrial fusion. Accordingly, stereometric analysis shows that decreasing DeltaPsi or ATP synthesis with respiratory inhibitors limits mtg- and AlF4-induced mitochondrial fusion. Also, a specific G protein inhibitor (Bordetella pertussis toxin) hyperpolarizes mitochondria and leads to a loss of AlF4-dependent mitochondrial fusion. These results place mtg-induced DeltaPsi changes upstream of AlF4-induced mitochondrial fusion, suggesting that GTPases exert DeltaPsi-dependent control of the fusion process. Mammalian mitochondrial morphology thus can be modulated by cellular energetics.  (+info)

Liposomes fuse with sperm cells and induce activation by delivery of impermeant agents. (7/3607)

Sperm cell activation is a critical step in fertilization. To directly investigate the cell signaling events leading to sperm activation it is necessary to deliver membrane impermeant agents into the cytoplasm. In this study, the use of liposomes as possible agent-loading vectors was examined using (1) the octadecylrhodamine B (R18) and NBD phosphatidylethanolamine (NBD DHPE)/rhodamine phosphatidylethanolamine (rhod DHPE) fusion assays in bulk samples, (2) membrane transfer of fluorescence from liposome membranes labeled with R18 and rhodamine-tagged phosphatidylethanolamine (TRITC DHPE), and (3) lumenal transfer of impermeant calcium ions from liposomes to sperm cells, a process that stimulated sperm cell activation. Intermediate-sized unilamellar liposomes (98.17+/-15.34 nm) were prepared by the detergent-removal technique using sodium cholate as the detergent and a phosphatidylcholine/phosphatidylethanolamine/cholesterol (2:1:1 mole ratio) lipid composition. In the R18 fusion assays, self-quenching increased logarithmically with increasing concentrations of R18 in the liposome membranes; addition of unlabeled sperm to R18-labeled liposomes lead to a rapid release of self-quenching. In the NBD DHPE/rhod DHPE resonance energy transfer (RET) fusion assay, RET was rapidly reduced under similar conditions. In addition, individual sperm became fluorescent when TRITC DHPE-labeled liposomes were incubated with unlabeled sperm cells. Incubation of sperm cells with empty liposomes did not significantly affect sperm cell activation and did not alter cell morphology. However, incubation with Ca (10 mM)-loaded liposomes resulted in a time-dependent increase in sperm cell activation (7.5-fold over controls after 15 min). We conclude that liposomes can be used for direct loading of membrane-impermeant agents into sea squirt sperm cell cytoplasm, and that delivery occurs via fusion and content intermixing.  (+info)

Effects of double-site mutations of vesicular stomatitis virus glycoprotein G on membrane fusion activity. (8/3607)

Site-directed mutagenesis of specific amino acids within a conserved amino-terminal region (H2) and a conserved carboxyl-terminal region (H10/A4) of the fusion protein G of vesicular stomatitis virus have previously identified these two segments as an internal fusion peptide and a region influencing low-pH induced conformational change, respectively. Here, we combined a number of the substitution mutants in the H2 and H10/A4 regions to produce a series of double-site mutants and determined the effect of these mutations on membrane fusion activity at acid pH and on pH-dependent conformational change. The results show that most of the double-site mutants have decreased cell-cell fusion activity and that the effects appeared to be additive in terms of inhibition of fusion, except for one mutant, which appeared to be a revertant. The double-site mutants also had pH optima for fusion that were lower than those observed with wild-type G but same as the pH optima for the parent fusion peptide (H2) mutants. The results suggest that although the H2 and H10/A4 sites may affect membrane fusion independently, a possible interaction between these two sites cannot be ruled out.  (+info)

Cell-cell fusion is critical for the conception, development, and physiology of multicellular organisms. Although cellular fusogenic proteins and the actin cytoskeleton are implicated in cell-cell fusion, it remains unclear whether and how they coordinate to promote plasma membrane fusion. We reconstituted a high-efficiency, inducible cell fusion culture system in the normally nonfusing Drosophila S2R+ cells. Both fusogenic proteins and actin cytoskeletal rearrangements were necessary for cell fusion, and in combination they were sufficient to impart fusion competence. Localized actin polymerization triggered by specific cell-cell or cell-matrix adhesion molecules propelled invasive cell membrane protrusions, which in turn promoted fusogenic protein engagement and plasma membrane fusion. This de novo cell fusion culture system reveals a general role for actin-propelledinvasive membrane protrusions in driving fusogenic protein engagement during cell-cell fusion.. ...
Cell fusion occurs throughout development, from fertilization to organogenesis. The molecular mechanisms driving plasma membrane fusion in these processes remain unknown. While yeast mating offers an excellent model system in which to study cell fusion, all genes previously shown to regulate the process act at or before cell wall breakdown; i.e., well before the two plasma membranes have come in contact. Using a new strategy in which genomic data is used to predict which genes may possess a given function, we identified PRM1, a gene that is selectively expressed during mating and that encodes a multispanning transmembrane protein. Prm1p localizes to sites of cell-cell contact where fusion occurs. In matings between Deltaprm1 mutants, a large fraction of cells initiate zygote formation and degrade the cell wall separating mating partners but then fail to fuse. Electron microscopic analysis reveals that the two plasma membranes in these mating pairs are tightly apposed, remaining separated only by ...
Common themes are emerging from the study of viral, cell-cell, intracellular, and liposome fusion. Viral and cellular membrane fusion events are mediated by fusion proteins or fusion machines. Viral fusion proteins share important characteristics, notably a fusion peptide within a transmembrane-anchored polypeptide chain. At least one protein involved in a cell-cell fusion reaction resembles viral fusion proteins. Components of intracellular fusion machines are utilized in multiple membrane trafficking events and are conserved through evolution. Fusion pores develop during and intracellular fusion events suggesting similar mechanisms for many, if not all, fusion events. ...
Experimental evidence points towards a remarkably conserved mechanism by which virally encoded envelope glycoproteins catalyse membrane fusion and facilitate delivery of the viral core into the target cell [13, 14]. The structures of several class 1 fusion proteins reveal a characteristic trimer-of-hairpins motif believed to represent a late or post-fusion conformation [16-19, 35-37]. Investigating the way in which envelope proteins fold from a rod-like, pre-hairpin intermediate into the trimer-of-hairpins to pull the viral and cellular membranes together is important not only for our understanding of viral entry but also for the development of therapeutically relevant inhibitors of this process.. The protein sequences of the TM ectodomains of BLV and HTLV-1 display a striking level of conservation. By scrutinizing the position of conserved residues in the context of the HTLV-1 six-helix-bundle structure, we have found that the majority of the conserved residues map to the interacting surfaces ...
SNARE-bound Sec1p strongly stimulates in vitro fusion. A twofold dilution series of Sec1p was bound to t-SNARE complexes (Sso1p/Sec9c) in detergent solution bef
Traditional functional assays such as hemagglutination inhibition (HAI) and micro-neutralization (MN) assays have been routinely used for assessing the vaccine response, since influenza vaccine has been administered in people (1940). Such assays are not always predictive regarding the protection conferred by the influenza vaccine and are not able to monitor neutralization related to stem region of influenza hemagglutinin responsible for virus membrane fusion in the endosomes. In order to study Influenza vaccine response in a more biomimetic manner and overcome the deficiencies of the traditional functional assays, we developed a fluorescent membrane fusion assay (fMF). The assay uses viruses labeled with Octadecyl Rhodmaine B Chloride (R18) to monitor two major neutralization pathways: blocking the attachment of virus to the target cells and blocking of virus membrane fusion in the endosomes. The latter was tested using endosomal acidification inhibitor Bafilomycin a1 which blocked membrane fusion by
TY - JOUR. T1 - Interhelical interactions in the gp41 core. T2 - Implications for activation of HIV-1 membrane fusion. AU - Wang, Shilong. AU - York, Joanne. AU - Shu, Wei. AU - Stoller, Marisa O.. AU - Nunberg, Jack H.. AU - Lu, Min. PY - 2002/6/11. Y1 - 2002/6/11. N2 - The human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein complex (gp120-gp41) promotes viral entry by mediating the fusion of viral and cellular membranes. Formation of a stable trimer-of-hairpins structure in the gp41 ectodomain brings the two membranes into proximity, leading to membrane fusion. The core of this hairpin structure is a six-helix bundle in which three carboxyl-terminal outer helices pack against an inner trimeric coiled coil. Here we investigate the role of these conserved interhelical interactions on the structure and function of both the envelope glycoprotein and the gp41 core. We have replaced each of the eight amino acids at the buried face of the carboxyl-terminal helix with a representative ...
Syntaxin N-terminal peptide motif is an initiation factor for the assembly of the SNARE-Sec1/Munc18 membrane fusion complex Journal Article ...
SARS-CoV-2 infection is initiated by virus binding to ACE2 cell surface receptors1-4, followed by fusion of virus and cell membranes to release the virus genome into the cell. Both receptor binding and membrane fusion activities are mediated by the virus Spike glycoprotein, S5-7. As with other class I membrane fusion proteins, S is post-translationally cleaved, in this case by furin, into S1 and S2 components that remain associated following cleavage8-10. Fusion activation following receptor binding is proposed to involve the exposure of a second proteolytic site (S2), cleavage of which is required for the fusion peptide release11,12. We have investigated the binding of ACE2 to the furin-cleaved form of SARS-CoV-2 S by cryoEM. We classify ten different molecular species including the unbound, closed spike trimer, the fully open ACE2-bound trimer, and dissociated monomeric S1 bound to ACE2. The ten structures describe ACE2 binding events which destabilise the spike trimer, progressively opening ...
Several viral envelope glycoprotein oligomers assembled into a viral fusion machine, form a molecular scaffold that brings the viral and target cell membranes into close apposition and allow the subsequent fusion events. The fusion pore formation and its sequential expansion are orchestrated by viral and cellular lipids and proteins. The HIV entry process is understood in some detail at the molecular level. It is coordinated by the HIV envelope glycoprotein complex, a trimer of three gp120 surface glycoproteins, each noncovalently attached to three gp41 ransmembrane glycoprotein subunits.%&/It is know that changes in GSLs expression in target membranes can modulate viral fusion and entry. These studies on structure-function relationship of target membrane GSLs, the gp120-gp41 and the viral receptors suggest that plasma membrane GSLs support HIV-1 entry by stabilizing the intermediate steps in the fusion cascade. These observations, led it to hypothesize that upregulation of GSLs metabolites ...
The vacuole system provides good tools to assay the abundance of the tagged SNAREs on the isolated organelle, dissect their molecular interactions, and to identify hemifusion intermediates. In contrast to previous studies on tagged synaptobrevin II in chromaffin cells, in which these molecular properties are hard to access [40], this allowed us to demonstrate that the effect of large luminal tags was restricted to content mixing, whereas lipid mixing was essentially unaffected. This suggests that mixing of the outer leaflets may be less dependent on a collective perturbation of lipid structure by SNARE TMDs than the rearrangement of the inner leaflets. It is consistent with theory and simulations on the energetics of SNARE‐driven fusion, which suggested that fusion pore opening is limited by a larger free energy barrier than the induction of hemifusion [38]. In line with this, opening of the fusion pore has been found to be rate‐limiting for vacuole fusion [22].. The observation that even ...
An analysis of the R18 fusion assay was made during the fusion of the Sendai virus with erythrocyte ghosts. The increase in R18 fluorescence, reflecting the interaction process, was evaluated in terms of the different processes that in principle may contribute to this increase, that is, monomeric probe transfer, hemifusion, and complete fusion. To this end, the kinetics of the R18-labeled lipid mixing were compared to those obtained with an assay in which the fusion-monitoring probe, eosin-maleimide, was attached to the viral surface proteins. The experiments relied on the use of native and fusion-inactive viruses and studies involving viral and target membranes that were modified by the incorporation of the lysophospholipid. The total dequenching signal detected in the R18 assay consists of components from probe transferred without fusion and from fusion itself. At 37 degrees C, the initial rate of dequenching (within two minutes) was predominately from the probe diluted by fusion with little
Role of the synaptobrevin C terminus in fusion pore formation.: Neurotransmitter release is mediated by the SNARE proteins synaptobrevin II (sybII, also known a
Using the well-established, stage-specific model of fully primed, fusion-ready CVs (Coorssen et al., 1998; Coorssen et al., 2003; Hibbert et al., 2005; Churchward et al., 2005), we find that raft integrity underlies the efficiency of fast, Ca2+-triggered native membrane fusion, but not the fundamental ability to fuse. Using selective methods, including enzymatic digestion and sequestration within the membrane (Churchward et al., 2005), we show that the integrity of microdomains rich in SM-CHOL correlates directly with Ca2+ sensitivity and late fusion kinetics. In terms of the Ca2+ sensitivity of triggered fusion, SM does not appear to contribute directly, but rather through its role as a microdomain organizer. Thus, unlike its neighboring CHOL molecules, SM is not an essential component of the minimal native fusion machine. As a microdomain organizer, SM is associated with Ca2+ sensing and/or the interaction of additional proteinaceous or lipidic components that support the physiological Ca2+ ...
Author: Ngatchou, A. N. et al.; Genre: Journal Article; Published in Print: 2010-10-26; Title: Role of the synaptobrevin C terminus in fusion pore formation.
Single-particle studies of dengue-virus membrane fusion and the effect of small-molecule inhibitors of infection clarify the viral fusion mechanism.
Abstract: The recent outbreak of coronavirus disease (COVID-19) caused by SARS-CoV-2 infection in Wuhan, China has posed a serious threat to global public health. To develop specific anti-coronavirus therapeutics and prophylactics, the molecular mechanism that underlies viral infection must first be defined. Therefore, we herein established a SARS-CoV-2 spike (S) protein-mediated cell-cell fusion assay and found that SARS-CoV-2 showed a superior plasma membrane fusion capacity compared to that of SARS-CoV. We solved the X-ray crystal structure of six-helical bundle (6-HB) core of the HR1 and HR2 domains in the SARS-CoV-2 S protein S2 subunit, revealing that several mutated amino acid residues in the HR1 domain may be associated with enhanced interactions with the HR2 domain. We previously developed a pan-coronavirus fusion inhibitor, EK1, which targeted the HR1 domain and could inhibit infection by divergent human coronaviruses tested, including SARS-CoV and MERS-CoV. Here we generated a series ...
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
E1 is a class II viral fusion protein. This trimeric (low-pH-iduced) form is fusion active, and promotes release of viral nucleocapsid in cytoplasm after cell and viral membrane fusion. Efficient fusion requires the presence of cholesterol and sphingolipid in the target membrane. N-terminal domain of this protein: 1dyl(NMR), 1vcp, 1vcq ...
Author: Lindau, M. et al.; Genre: Journal Article; Published in Print: 1995-08; Open Access; Title: Structure and function of fusion pores in exocytosis and ectoplasmic membrane fusion.
The SNARE hypothesis states that the folding and assembly of four-helix SNARE complex bundles drives intracellular membrane fusion, including fusion in exocytos...
Since eukaryotic intracellular region is compartmentalized by dynamic lipid bilayer membranes, biomolecules are transported via vesicles. At the target site, vesicles transfer the biomolecules by fusing with the target membrane. The membrane fusion between vesicles and plasma membrane involves protein supramolecular complex called tethering factor (Exocyst) that loosely and reversibly tethers both the membranes, and SNARE complex that fuses the vesicular and plasma membranes. Such sequential membrane fusion reactions mediated by protein-protein interactions are regulated by specific small GTPases such as Rab. Our laboratory determines the ternary structures of the complexes of small GTPases and their effectors, which are devoted for exocytosis, to elucidate the fundamental mechanism of membrane fusion regulated by small GTPases.. ...
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Regulated exocytosis is a stimulus-dependent membrane fusion event of fundamental importance to a range of physiological processes. The membrane fusion reaction...
The possibility that isomerization controls the fusion activity was tested by analysing Mo‐MLV fusion and infectivity under conditions that either inhibited or induced isomerization. The fusion was studied as virus‐induced polykaryon formation in XC cells (fusion‐from‐without). Fusion of cell‐bound virus is induced by incubation at 37°C and terminated by pH 3.0 treatment. In confluent cultures (Figure 6A), the fusion will merge cells, and with time these will rearrange into polykaryons (Figure 6B). Preliminary testing demonstrated that TN/1.8 mM Ca2+ supported fusion as effectively as DMEM (data not shown). Therefore, TN/1.8 mM Ca2+ was used as the control condition. The time course of the fusion process is shown in Figure 6C.. We first studied the effect that alkylation‐mediated inhibition of isomerization had on fusion. To avoid adverse effects due to alkylation of internal viral proteins, we used the membrane‐impermeant reagents M135 and MTSET. We observed a ...
[BioChemistry] Vaccinia A27 Protein Structure is Revealed to Regulate Virus and Host Cell Membrane Fusion (Chinese Version) Academia Sinica Newsletter (2013/08/27) Two research teams in Academia Sinica, Dr. Andrew H.-J.
Alphaviruses, single-stranded RNA viruses within the Togaviridae family, are important human and animal pathogens. These viruses invade the host cells through the receptor-mediated endocytosis pathway. The acidic environment in the endosome induces fusion of the viral envelope and the endosomal membrane, allowing delivery of the viral genomic material into the cytoplasm of the infected cell. The energy cost for merging the hydrated membranes is endowed with the conformational changes and oligomeric rearrangements of the viral E1 glycoproteins, a class-II fusion protein. Although the crystal structures of the E1 ecto-domain in pre- and post-fusion conformations were determined, the structural details of the intermediate organizations of the fusion protein during the course of membrane fusion are poorly understood. Major obstacles that have impeded vigorous structural studies are the aggregation and heterogeneity of virus particles at low-pH, and additive heterogeneity introduced by non-uniform ...
Fusion pore regulation of transmitter release.: During the last decade a wealth of new information about the properties of the exocytotic fusion pore is changin
Here are some pics that will show how far I can twist with a T2-pelvic fusion. I also have pics of my rib hump, which is now much less. I still have about 30 degrees rotation in my vert, verified by my cts. My hump was much worse before my surgeries. Hopes this gives some idea as to limitations after a full fusion. Ed
Visualizing the location and dynamics of exocytosis Toomre et al. use a combination of TIR microscopy (green, labeling molecules close to or at the membrane) and standard fluorescence microscopy (red, for molecules further from the membrane) to visualize trafficking to and fusion with the plasma membrane during exocytosis. Red dots turn yellow then green as they approach the membrane, and then explode in a burst of light as they fuse with the plasma membrane during exocytosis. The transport containers appear to be partially anchored at the membrane before fusion, and can undergo either partial or complete fusion events ...
Fusion Antibodies provide a range of antibody engineering services for the development of antibodies for both therapeutic drug and diagnostic applications
Antiviral blocking peptides targeting the viral fusion core can inhibit viral membrane fusion, thereby inhibiting the viruss entry into the host cell.
Description Recombinant SARS-COV-2 S1+S2 ECD(S-ECD) Protein is produced by HEK293 cells expression system. The target protein is expressed with sequence (Val11-Gln1208) of SARS-COV-2 S1+S2 ECD(S-ECD) (Accession...
The IR-110 A is the new generation of infrared fusion machines. Automation and intuitive handling enable highest efficiency for installers and operators.
The IR-110 A is the new generation of infrared fusion machines. Automation and intuitive handling enable highest efficiency for installers and operators.
hardware after fusion - MedHelps hardware after fusion Center for Information, Symptoms, Resources, Treatments and Tools for hardware after fusion. Find hardware after fusion information, treatments for hardware after fusion and hardware after fusion symptoms.
Protein transport in eukaryotic cells requires the selective docking and fusion of transport intermediates with the suitable goal membrane. t-SNARE molecules which can be related to distinct intracellular compartments could function receptors for transport vesicle docking and membrane fusion by means of interactions with particular v-SNARE molecules on vesicle membranes, offering the inherent specificity of those reactions. VAM3 encodes a 283-amino acid protein that shares homology with the syntaxin household of t-SNARE molecules. Polyclonal antiserum raised in […]. ...
but why is there no ABS even as an option on Fusion D ? I would have chosen this vehicle if it was with ABS but now a definite NO NO as I know the consequences of a high speed braking going bad for a
Spinal self fusion usually is a prolonged process, and the outcome cannot be predicted as the fusion can be irregular. Consult a doctor now.
A workshop on fusion technology beyond ITER was successfully held between the Japanese and the Korean Domestic Agencies on 8-9 November at the National Fusion [...]
4I78: Hemagglutinin homologue from H17N10 bat influenza virus exhibits divergent receptor-binding and pH-dependent fusion activities.
Aguilar, P.S., Baylies, M.K., Fleissner, A., Helming, L., Inoue, N., Podbilewicz, B., Wang, H., and Wong, M. (2013). Genetic basis of cell-cell fusion mechanisms. Trends in genetics : TIG 29, 427-437 ...
Exceptionally high reaction gains of hydrogen protons measured with the boron isotope 11 are compared with other fusion reactions. This is leading to the
Provides in-depth assessment of 500+ genes associated with fusions in cancer, including solid tumors, soft tissue cancers and hematological malignancies. Delivers detected fusions in a simple report.
Are you looking for a unique way of getting fit? Try fusion. A fusion workout blends different disciplines or different styles within a discipline to offer variety and a more complete workout. Here, we look at four variations:
For enveloped viruses, fusion of the viral envelope with a cellular membrane is critical for a productive infection to occur. This fusion process is mediated by at least three classes of fusion proteins (Class I, II, and III) based on the protein seq ...
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The membrane fusion and cell swelling stages of Sendai virus-mediated cell-cell fusion have been studied by thin-section and freeze-fracture electron microscopy. Sites of membrane fusion have been detected in human erythrocytes arrested at the membrane fusion stage of cell fusion and in virtually all cases a fused viral envelope or envelope components has been identified thus providing further direct evidence that cell-viral envelope-cell bridge formation is the membrane fusion event in Sendai virus-induced cell fusion. Radial expansion of a single virus bridge connecting 2 cells is sufficient to produce a fused cell. Membrane redistribution which occurs during this cell swelling stage of the fusion process is often accompanied by the formation of a system of membrane tubules in the plane of expansion of the virus bridge. The tubules originate from points of fusion between the bridging virus envelope and the erythrocyte membrane and also expand radially as cells swell. Ultimately membrane ...
Regulation of glucose uptake in muscle and adipose tissues by insulin is of fundamental importance for proper maintenance of postprandial hyperglycemia. This hormone stimulates translocation of the GLUT4 glucose transporter from the intracellular membrane to the cell surface (1,2). In addition to this movement of intracellular vesicles containing GLUT4, it has been suggested that the docking and fusion step of GLUT4 vesicles is also critically regulated by insulin (3,4,23). However, the precise mechanism by which insulin regulates vesicle fusion is still largely unknown.. A key finding of this study is identification of the double C2 domain protein DOC2b, which mediates insulin-regulated GLUT4 vesicle fusion. Like other membrane fusion processes, GLUT4 vesicle fusion occurs essentially through the formation of a core complex consisting of syntaxin-4 and VAMP-2 (5). In general, however, a number of additional factors are required to bring about SNARE-mediated membrane fusion in vivo. Many of ...
In the neuron, neurotransmitter release is mediated by SNARE (soluble NSF (N-ethylmaleimide-sensitive factor) attachment protein receptor) proteins. SNARE-dependent synaptic vesicle membrane and plasma membrane fusion is a multiple-step event and a tightly regulated process. Vesicle-anchored (v-) SNARE from synaptic vesicles associates with target plasma membrane-anchored (t-) SNARE to form a trans-SNAREpin complex. When the triggering signal arrives, v-SNARE and t-SNARE mediate the membrane full fusion and extend on one side of the membrane, forming a cis-conformation. During the whole process, SNARE complex with the help of regulators overcomes the energy barriers to fuse two apposed membranes and ensures that fusion proceeds at the correct time and place. Currently, there are some key questions that remain regarding SNARE-mediated exocytosis regulation. First, among the SNARE regulators, complexin is a small SNARE-binding protein that is thought to inhibit membrane fusion before Ca2+ triggering
As for most cell-cell fusion events, the molecular details of membrane fusion during yeast mating are poorly understood. The multipass membrane protein Prm1 is the only known component that acts at the step of bilayer fusion. In its absence, mutant mating pairs lyse or arrest in the mating reaction with tightly apposed plasma membranes. We show that deletion of FIG 1, which controls pheromone-induced Ca(2+) influx, yields similar cell fusion defects. Although extracellular Ca(2+) is not required for efficient cell fusion of wild-type cells, cell fusion in prm1 mutant mating pairs is dramatically reduced when Ca(2+) is removed. This enhanced fusion defect is due to lysis. Time-lapse microscopy reveals that fusion and lysis events initiate with identical kinetics, suggesting that both outcomes result from engagement of the fusion machinery. The yeast synaptotagmin orthologue and Ca(2+) binding protein Tcb3 has a role in reducing lysis of prm1 mutants, which opens the possibility that the observed ...
UniProt ITasser SWISS Models alphafold D3Targets-2019-nCoV Spike protein S1 (residue 14-685): attaches the virion to the cell membrane by interacting with host receptor, initiating the infection. Binding to human ACE2 and CLEC4M/DC-SIGNR receptors and internalization of the virus into the endosomes of the host cell induces conformational changes in the S glycoprotein. Proteolysis by cathepsin CTSL may unmask the fusion peptide of S2 and activate membranes fusion within endosomes.Spike protein S2 (residue 686-1273): mediates fusion of the virion and cellular membranes by acting as a class I viral fusion protein. Under the current model, the protein has at least three conformational states: pre-fusion native state, pre-hairpin intermediate state, and post-fusion hairpin state. During viral and target cell membrane fusion, the coiled coil regions (heptad repeats) assume a trimer-of-hairpins structure, positioning the fusion peptide in close proximity to the C-terminal region of the ectodomain. The ...
The synaptic vesicle protein synaptobrevin (VAMP) has recently been implicated as one of the key proteins involved in exocytotic membrane fusion. It interacts with the synaptic membrane proteins syntaxin I and synaptosome-associated protein (SNAP)-25 to form a complex which precedes exocytosis [Söll …
Syb homologues have been shown to influence fusion pore stability (Borisovska et al., 2005), and this is consistent with the present findings. However, in contrast to rate processes leading to fusion pore opening, the sites that influence the stability of an open fusion pore are scattered through the SNARE complex. Only about half of the mutations tested had a statistically significant effect, and of those the majority (11/15) were in membrane-distal negative layers (Fig. 5). Because the effects on the initial and sustained rates indicated that the SNARE complex is already fully assembled by the time the fusion pore opens, the patchy distribution of effects on fusion pore stability may mean that the SNARE complex partially disassembles, either once the fusion pore is open or as it starts to dilate. Reassembly or a structural transition in the membrane-distal regions (which have stronger effects on PSF duration) would then play a critical role in transitions arising from open fusion pores. ...
Dynamics of fluorescence dequenching of ostrich-quenched fluorescein biotin: A multifunctional quantitative assay for biotins profile, publications, research topics, and co-authors
New 3-D maps of water distribution during cellular membrane fusion are accelerating scientific understanding of cell development, which could lead to new treatments for diseases associated with cell fusion. Using neutron diffraction at the Department of Energys Oak Ridge National Laboratory, researchers have made the first direct observations of water in lipid bilayers used to model cell membrane fusion.
Our studies show that vacuole-bound actin is needed for homotypic fusion of this organelle in the absence of cytoskeleton or cytosol. Proteins of the well-established pathways of actin cytoskeleton regulation are needed for normal vacuole structure in vivo (Fig. 2 A) and are found on purified vacuoles at levels which cannot be due to cytosolic contamination (Fig. 2 B). Antibody to the Las17p/Bee1p, the yeast WASp homologue, inhibits vacuole fusion (Fig. 3), and this inhibition can be modulated (Fig. 3 C) by high levels of either the WCA domain of Las17p or by calmodulin, which are known to interact directly with Arp2/3 complex. Antibody to Arp3p itself also blocks vacuole fusion (Fig. 3 D). Mutations in actin have striking effects on vacuole structure in vivo (Fig. 2 A) and fusion in vitro (Fig. 4), and well-studied actin ligands (Morton et al., 2000) show fusion stage-specific inhibition of the vacuole fusion reaction (Figs. 5 and 6). We found that blocking F-actin depolymerization ...
Maintenance of eukaryotic cellular homeostasis requires the fusion of vesicle membranes that is accomplished by a SNARE-mediated mechanism. Membrane fusion is the merger of two lipid bilayers into one continuous membrane. Multiprotein complexes that have been conserved in eukaryotes carry out the basic reactions of fusion. In Saccharomyces cerevisiae, homotypic vacuole fusion occurs in experimentally defined phases. Fusion priming does not involve contact between vacuoles but includes the disassembly of complexes of SNAREs on the same membrane (cis) by Sec18p (NSF) and its cochaperone Sec17p (a-SNAP). Tethering requires Ypt7p (a Rab GTPase) and the HOPS effecter complex. SNARE complexes, including one R SNARE from a donor vacuole and three Q SNAREs from the acceptor vacuole, are formed in trans during docking of vacuoles. The membranes of the docked vacuoles are drawn together to form the boundary domain that resembles flat discs. The outer membranes are not in contact and come together at the ...
For the 15 years or so, we have developed a series of reconstitution platforms to investigate the molecular mechanism of SNARE-mediated membrane fusion, and the regulation of this process by regulatory factors. In 1998, we established the central function of the SNARE proteins as fusogens when we reconstituted these proteins into small unilamellar vesicle (SUV) and measured lipid mixing between liposomes containing cognate SNARE proteins.. We have since demonstrated SNARE-mediated fusion by reconstituting SNAREs into giant unilamellar vesicle (GUV, shown in Figure 1) and supported bilayer (SBL, shown in Figure 2). Both of the systems provided flat, and therefore, more physiologically relevant membrane environment on the t-SNARE side. In the SUV-SBL fusion system, we have measured single fusion event in millisecond time-scales.. ...
Membrane fusion, the merger of two biological membranes without content leakage, is essential for protein transport along the exocytic and endocytic pathways in eukaryotic cells. Fusion requires conserved membrane‐anchored proteins named SNAREs (αSNAP receptors) (Wickner and Schekman, 2008; Sudhof and Rothman, 2009), which reside on both the donor and acceptor membranes. SNAREs form four helical coiled‐coil bundles through their heptad‐repeat SNARE domains. Cis‐SNARE complexes are disassembled by Sec17p/αSNAP and Sec18p/NSF in an ATP‐dependent step called priming. Liberated SNAREs from apposed membranes form trans‐SNARE complexes, an essential step for fusion. Other proteins cooperate with the SNAREs to achieve fusion. Rab GTPases and their effectors promote the tethering of donor and acceptor membranes (Grosshans et al, 2006; Markgraf et al, 2007; Hickey and Wickner, 2010) and thereby indirectly promote trans‐SNARE complex formation. Sec1p/Munc18 (SM) proteins bind individual ...
Lysolipids added between fusing membranes inhibit and cis-unsaturated fatty acids promote not only diverse biological fusion reactions (this paper and Creutz, 1981; Glick and Rothman, 1987; Chernomordik et al., 1993; Paiement et al., 1994; Yeagle et al., 1994; Chernomordik et al., 1995c; Gunther-Ausborn et al., 1995; but see Nagao et al., 1995; Coorssen, 1996), but also fusion of purely lipid bilayers (for review see Chernomordik et al., 1995b). Importantly, LPC inhibits HA-mediated fusion at membrane concentrations similar to those found to inhibit syncytia formation mediated by the Sendai virus F protein (Yeagle et al., 1994) and baculovirus gp64 (Chernomordik et al., 1995c), as well as for microsome-microsome fusion (Chernomordik et al., 1993) and vesicle-planar bilayer fusion (Chernomordik et al., 1995a). We suggest that fusion mediated by HA and other proteins and fusion of purely lipid bilayers proceed via a common lipid-involving intermediate-a stalk structure, producing local and ...
The Karlsruhe International School on Fusion Technologies has been held since 2007 at the Karlsruhe Institute of Technology (KIT, formerly Forschungszentrum Karlsruhe). It started as the Fusion Summer School, with the aim of expanding the knowledge of young international scientists on the process of nuclear fusion. Leading scientists from KIT as well as international partners lead the program lectures. The annual Karlsruhe International School on Fusion Technologies gives an overview on key fusion technologies, their current status, and on long term R&D-particularly in view of the next step beyond ITER, the demonstration power station DEMO. The next International School will take place on line (due to the COVID-19 situation) from 30 September to 8 October 2020. Click here for all information.
Vesicle associated membrane proteins are members of the soluble N-ethyl-maleimide-sensitive factor receptor (SNARE) attachment protein family that facilitate the intracellular membrane fusion process involved in neurotransmitter release (Ungar & Hughson, 2003). Cellubrevin, or VAMP-3, is similar to SNARE proteins, synaptobrevin 1 and 2 (VAMP-1 and 2), but can be found in many different tissues such as fibroblasts, adipose cells, insulin-secreting B cells, and supportive brain cells like glial, but not brain neuron cells (Chilcote et al., 1995). However cellubrevin is also a substrate for proteolytic action of tetanus toxin just like VAMP-1 and 2, and suggests similar roles in exocytosis due to the blocking of neurotransmitter release in the presence of tetanus (Chilcote et al., 1995). Cellubrevin has been found to be significant in the docking and vesicle fusion process of secretory granules to the plasma membrane, but few studies in the immunofluorescence localization on subcellular fractions ...
2KXA: The complete influenza hemagglutinin fusion domain adopts a tight helical hairpin arrangement at the lipid:water interface.
Our approach described here provides a general avenue for observing single-liposome fusion events in proteoliposome systems (9, 12, 15, 34-36). Modification of the more conventional bulk-phase assays was kept minimal; one type of proteoliposome was attached to a nonsticky surface via specific interaction. Comprehensive controls and calibrations demonstrated that in vitro fusion activity in bulk solution is preserved in single-liposome fusion on surface. Real-time monitoring of SNARE-mediated, single-liposome fusion has revealed several key features: existence of hemifusion and additional intermediates on the pathway to full fusion and kinetic information on individual intermediate states. Furthermore, our assay might enable the dissection of the different fates of liposomes after fusion, for example, kiss-and-run type detachment. We should, however, emphasize that our work is based on yeast SNAREs and with a relatively high protein-to-lipid ratio (1:100) and therefore does not yet address the ...
EFF-1 and AFF-1 can fuse epithelial and myoepithelial cells in C. elegans, in heterologous Sf9 insect cells and in BHK hamster cells. This is a proof of principle that will allow us to test potential fusogens involved in mammalian myoblast fusion [5,10,11]. While candidates for muscle fusogens exist in Drosophila and vertebrates [1,12,13] none of these candidates has been shown to be both essential and sufficient for the cell membrane fusion process. Instead, the many genes involved in muscle cell fusion may be acting in earlier stages in the process that include: cell cycle arrest, recognition, alignment and adhesion (Fig. 1). We use a molecular genetic approach to identify the mammalian myoblast fusogen using expression of candidate genes in BHK cells and complementation of a C. elegans eff-1 deletion mutant with cross species expression of mouse cDNAs expressed during muscle formation. The approach and rationale is novel, risky and with extremely high potential of making a very important ...
Vesiculoviruses enter cells by membrane fusion, driven by a large, low‐pH‐induced, conformational change in the fusion glycoprotein G that involves transition from a trimeric pre‐fusion toward a trimeric post‐fusion state via monomeric intermediates. Here, we present the structure of the G fusion protein at intermediate pH for two vesiculoviruses, vesicular stomatitis virus (VSV) and Chandipura virus (CHAV), which is responsible for deadly encephalopathies. First, a CHAV G crystal structure shows two intermediate conformations forming a flat dimer of heterodimers. On virions, electron microscopy (EM) and tomography reveal monomeric spikes similar to one of the crystal conformations. In solution, mass spectrometry shows dimers of G. Finally, mutations at a dimer interface, involving fusion domains associated in an antiparallel manner to form an intermolecular β‐sheet, affect G fusion properties. The location of the compensatory mutations restoring fusion activity strongly suggests that ...
The target of human immunodeficiency virus type 1 (HIV-1) neutralizing antibodies (Abs) is the putative trimer of gp120-gp41 heterodimers that decorates the surface of HIV-1 (10, 28, 43, 52, 54). In the case of gp41, it appears that antibody access to neutralizing epitopes may be more restricted than access to those on gp120, since the relevant epitopes on gp41 probably become fully exposed only during HIV-1 envelope-mediated virus-cell membrane fusion (4, 19, 20, 46). The two anti-gp41 monoclonal Abs (MAbs) that are the most potent and broadly neutralizing are the human immunoglobulin G (IgG) MAbs 2F5 and 4E10 (12, 14, 16, 21, 47, 49, 58). The core epitope of 2F5, the most studied of the two MAbs, has been defined conveniently by a short linear sequence, ELDKWA, which is found at the extreme C-terminal end of the C-heptad repeat region on the ectodomain of gp41 (37). MAb 4E10 appears to recognize an epitope immediately C-terminal to the 2F5 epitope. The 4E10 epitope has been defined by the ...
The gH/gL heterodimer represents two from the four herpes virus glycoproteins sufficient and essential for membrane fusion. the HSV fusion glycoproteins is normally gL GSK2118436A which includes 224 proteins with no apparent transmembrane domains. The essential membrane proteins gH binds gL most GSK2118436A likely in the endoplasmic reticulum (ER) as well as the matching gH/gL heterodimer after that transits to sites of viral envelopment as well as the plasma membrane (4 5 An unchanged HSV type 1 (HSV-1) gH wont leave the ER unless it really is destined to gL (4 -7). The gH/gL heterodimer continues to be postulated to really have the hallmarks of the viral fusion proteins and to enjoy a direct function in membrane fusion (8 -13). Nevertheless the HSV-2 gH/gL framework will not resemble any known viral fusion proteins and there is certainly recent proof that HSV gH/gL has even more of a regulatory and/or structural function in membrane fusion performed by the course III fusion proteins gB (14 ...
The goals of this study were to build a yeast platform for the secretion of a variety of scFv/scTCR GFP fusion proteins and to understand the effects that fusion protein construction can have on intracellular fusion protein processing. A large collection of 27 GFP fusion proteins having scFv/scTCR fusion partners representative of a wide range of secretion fitnesses was analyzed. It was discovered that the fusion secretion levels were governed by scFv/scTCR secretion fitness, rather than by GFP, linker length, or fusion orientation. In addition, type III fusions were the most fluorescent with the least amount of observed degradation, and therefore, they represent the recommended construct for secretion of GFP fusions from yeast. Finally, fusion to GFP clearly affected the intracellular processing of the scFv/scTCR, and in particular helped promote the exit of mature protein from the cell. Finally, large amounts of fully active fusion protein accumulated inside the cell as a result of secretory ...
Flavivirus envelope protein (E) mediates membrane fusion and viral entry from endosomes. A low-pH induced, dimer-to-trimer rearrangement and reconfiguration of the membrane-proximal stem of the E ectodomain draw together the viral and cellular membranes. We found stem-derived peptides from dengue virus (DV) bind stem-less E trimer and mimic the stem-reconfiguration step in the fusion pathway. We adapted this experiment as a high-throughput screen for small molecules that block peptide binding and thus may inhibit viral entry. A compound identified in this screen, 1662G07, and a number of its analogs reversibly inhibit DV infectivity. They do so by binding the prefusion, dimeric E on the virion surface, before adsorption to a cell. They also block viral fusion with liposomes. Structure-activity relationship studies have led to analogs with submicromolar \(IC_{90} s\) against DV2, and certain analogs are active against DV serotypes 1,2, and 4. The compounds do not inhibit the closely related ...
Flavivirus envelope protein (E) mediates membrane fusion and viral entry from endosomes. A low-pH induced, dimer-to-trimer rearrangement and reconfiguration of the membrane-proximal stem of the E ectodomain draw together the viral and cellular membranes. We found stem-derived peptides from dengue virus (DV) bind stem-less E trimer and mimic the stem-reconfiguration step in the fusion pathway. We adapted this experiment as a high-throughput screen for small molecules that block peptide binding and thus may inhibit viral entry. A compound identified in this screen, 1662G07, and a number of its analogs reversibly inhibit DV infectivity. They do so by binding the prefusion, dimeric E on the virion surface, before adsorption to a cell. They also block viral fusion with liposomes. Structure-activity relationship studies have led to analogs with submicromolar \(IC_{90} s\) against DV2, and certain analogs are active against DV serotypes 1,2, and 4. The compounds do not inhibit the closely related ...
GO Terms Descrition:, negative regulation of transcription from RNA polymerase II promoter, DNA binding, nucleus, multicellular organismal development, epidermal cell fate specification, embryonic body morphogenesis, sequence-specific DNA binding, plasma membrane fusion, positive regulation of transcription from RNA polymerase II promoter, formation of anatomical boundary, locomotion, embryo development ending in birth or egg hatching, regulation of transcription, DNA-templated ...
Nazarul Hasan is the author of this article in the Journal of Visualized Experiments: Analysis of SNARE-mediated Membrane Fusion Using an Enzymatic Cell Fusion Assay
Successful infection by influenza virus requires that the envelope spike protein, hemagglutinin (HA), catalyzes fusion between the viral envelope and the intracellular endosomal membrane of the target cell and creates a pore large enough to release the viral genome. There is a growing appreciation that membrane lipids play a role in this critical event, coming mostly from experiments and theory on lipid composition in relationship to membrane monolayer curvature stress (Markin et al., 1984; Kozlov et al., 1989; Chizmadzhev et al., 1995; Chernomordik, 1996; Siegel, 1999; Kuzmin et al., 2001; Kozlovsky and Kozlov, 2003; Chernomordik et al., 2006). Recently there has been consideration given to the role of membrane phase behavior and membrane microdomains on the lateral distribution, sorting, and interactions of lipids with membrane proteins in general, and viral envelope glycoproteins in particular (Brown and London, 1998; Wang et al., 2001; Suomalainen, 2002; Chazal and Gerlier, 2003; Edidin, ...
You achieved immediate and lasting fame with your novel about the plain but spirited governess, Jane Eyre. The only Bronte sibling to marry, you outlived your brother and sisters, and, unlike Anne and Emily, had a chance to enjoy your celebrity and meet other authors of your day. However, you died in early pregnancy before you were forty ...
Motivation: Membrane fusion constitutes a key stage in cellular processes such as synaptic neurotransmission and infection by enveloped viruses. Current experimental assays for fusion have thus far been unable to resolve early fusion events in structural detail. We have previously used molecular dynamics simulations to develop mechanistic models of fusion by small lipid vesicles. Here, we introduce a novel structural measurement of vesicle topology and fusion geometry: persistent voids. Results: Persistent voids calculations enable systematic measurement of structural changes in vesicle fusion by assessing fusion stalk widths. They also constitute a generally applicable technique for assessing lipid topological change. We use persistent voids to compute dynamic relationships between hemifusion neck widening and formation of a full fusion pore in our simulation data. We predict that a tightly coordinated process of hemifusion neck expansion and pore formation is responsible for the rapid vesicle ...
Our present study has shown that the epitopes for MAbs 6-7 and 21-1 are cryptic in the cell surface-localized native WR F protein. By contrast, they are exposed on the surface-localized native L22P. Importantly, both the epitopes are also exposed on the Se-L22P mutant, an uncleaved form of L22P, which does not induce cell fusion unless it is cleaved by acetylated trypsin. Therefore, the epitopes for MAbs 6-7 and 21-1 seem readily exposed on the surface-localized L22P before undergoing conformational changes that lead to cell fusion. We have therefore concluded that there is a striking difference in the native (prefusion) conformation between nonfusogenic WR F protein and its fusogenic mutant, L22P. It should be stressed, however, that our present data do not exclude the possibility that the MAb epitopes may also be present in the postfusion conformation of L22P.. The epitopes for MAbs 6-7 and 21-1 in the WR F protein could be exposed by heating at 47°C as efficiently as could those in L22P ...
The Golgi apparatus is a membrane-bounded organelle with the characteristic shape of a series of stacked flat cisternae. During mitosis in mammalian cells, the Golgi apparatus is once fragmented into small vesicles and then reassembled to form the characteristic shape again in each daughter cell. The mechanism and details of the reassembly process remain elusive. ...We show that the characteristic Golgi shape is spontaneously organized from the assembly of vesicles by proper tuning of the two additional mechanisms, i.e., the Golgi reassembly process is modeled as self-organization. We also demonstrate that the fine Golgi shape forms via a balance of three reaction speeds: vesicle aggregation, membrane fusion, and shape relaxation. Moreover, the membrane fusion activity decreases thickness and the number of stacked cisternae of the emerging shapes ...
Controlled thermonuclear fusion may become an attractive future electrical power source. The most promising of all fusion machine concepts is called a tokamak. The fuel, a plasma made of deuterium and tritium, must be confined to enable the fusion process. It is also necessary to protect the wall of tokamaks from erosion by the hot plasma. To increase wall lifetime, the high-Z metal tungsten is foreseen as wall material in future fusion devices due to its very high melting point. This thesis focuses on the following consequences of plasma impact on a high-Z wall: (i) erosion, transport and deposition of high-Z wall materials; (ii) fuel retention in tokamak walls; (iii) long term effects of plasma impact on structural machine parts; (iv) dust production in tokamaks.. An extensive study of wall components has been conducted with ion beam analysis after the final shutdown of the TEXTOR tokamak. This unique possibility offered by the shutdown combined with a tracer experiment led to the largest ...
View Notes - BIOS41_Lecture16_02222008 from BIOS 41 at Lehigh University. transport vesicles to their target membranes. 15_21_membr_fusion.jpg SNARE proteins play a central role in membrane fusion.
This entry includes information about the spike protein such as its function, structure, and interaction with different ACE2 receptors. The function of spike protein S1 is to initiate infection by attaching the virion to the host cell receptor. Spike protein S2 acts as a class I viral fusion protein and mediates fusion of the virion and hots cell membrane. Spike protein S2 is a viral fusion peptide that is unmasked following S2 cleavage, which occurs during the viruss endocytic entry into the host cell ...
LPC inhibits vacuole fusion. (A) Titration of four different LPCs. Standard fusion reactions were incubated at 27°C in the presence of the indicated inhibitors
Brought down to earth, nuclear fusion - a process fuelled primarily by lithium and deuterium (an isotope of hydrogen), both of which are plentiful in seawater and in the earths crust -could provide a major source of low-carbon energy. A fusion power station would use only around 450kg of fuel annually, cause no atmospheric pollution, and carry no risk of accidents that could lead to radioactive contamination of the environment.. But, while the fusion process has produced some energy (16 million watts of it, to be specific), scientists have yet to create a self-sustaining fusion burn. Indeed, unlike nuclear fission, which went from the laboratory to the power grid within two decades, fusion has proved a tough nut to crack.. The problem is that fusion involves joining two positively charged nuclei - and, as basic science shows, same-sign charges repel each other. Only at extremely high temperatures - over 100 million degrees Celsius, or almost 10 times hotter than the sun - do the nuclei move ...
The world of fusion energy is a world of extremes. For instance, the center of the ultrahot plasma contained within the walls of doughnut-shaped fusion machines known as tokamaks can reach temperatures well above the 15 million degrees Celsius core of the sun. And even though the portion of the plasma closer to the tokamaks inner walls is 10 to 20 times cooler, it still has enough energy to erode the layer of liquid lithium that may be used to coat components that face the plasma in future tokamaks. ...
Novelty: suggest an explanation for one clinical symptom (lymphocytopenia) Standing in the field: first paper to show that SARS-CoV-2 Spike fusion enables viral entry into human T cell lines. Appropriate statistics: unpaired t-test performed in some graphs but no information about replicates reduce considerably the robustness! Viral model used: pseudoviruses - SARS-CoV and SARS-CoV2 Translatability: Need to perform similar study on primary T cells (from healthy and patient donors) before evoking therapeutic interventions. Main limitations: - in vitro, on cell lines and not primary human cells - Did not measure ACE2 protein expression on T cell lines, and did not include a negative control sample for ACE2 mRNA - Did not provide negative or toxicity controls for EK1 peptide effect - Do not provide information about the number of replicates - Inconsistency between 2 figures (1c and 1d - infection ability on MT-2 2000RLU then 8000) - Very subtle shift on the MT2 infection FACS plot (Fig. 1f), no ...
This finding deals with one of the most fundamental reactions in a cell, how membranes fuse with each other. It is important to understand how this works, because when these events go wrong, either accelerating or slowing down, then it can affect certain disorders such as tumor formation, Peters said. By using our physiological yeast fusion model, the impact of these tethering factors on the SNARE topology can be investigated, along with the many other factors that come into play. This was not the case in the artificial liposome models used in the past.. Others who contributed to the study include: Kannan Alpadi, Aditya Kulkarni and Sarita Namjoshi, all with the department of biochemistry at BCM; and Veronique Comte, Monique Reinhardt, Andrea Schmidt and Andreas Mayer, all with the department of biochemistry at the University of Lausanne, Switzerland.. Funding for this study came from the National Institutes of Health and Boehringer Ingelheim.. ...
If there is any sort of financial, climatic and/or conflict-based interruptions to the industrial infrastructure, I have to wonder whether that will be a very sudden end to what we think of as a modern life, because it just doesnt seem possible to me to re-manufacture, e.g., an oil-rig without an initial input of energy to do it, and without the oil-rigs wed not be able to drill down 5 miles under the sea where the oil is these days. It was easy when humans started down this route of burning fossil fuels because the stuff was just laying there in pools on the surface! Imagine that over again, and we didnt have that to start with. How far would we have got if all the oil had been 5 miles under the seabed ...
Nuclear fusion is when the nuclei of a pair or more of atoms become fused together. The fusion of the atoms releases large amounts of energy. Nuclear fusion is what powers stars in space and has also been achieved within a human laboratory. While nuclear fusion could hypothetically be used as a source of terrestrial power, this has proven to be quite difficult. Surrounding each atom is a positively charged field known as the electrostatic force that tends to repel other atoms away before a pair of atoms can become close enough for their nuclei to fuse. It requires massive amounts of energy to overcome the repulsion of the electrostatic forces between neighboring atoms. Although the development of a nuclear fusion reactor has been a high priority for many governments around the world for many decades, nuclear fusion reactions being carried out in a laboratory have yet to result in a sustainable fusion chain reaction as it seems to require more energy to cause atoms to fuse than what is actually ...
Lukas Tamm, PhD, chats with Biophysical Society TV - giving us an overview of this important Wednesday, February 18, 2014 Symposium at the 2014...
An investigation was conducted to study the nuclear design aspects of using very low activation materials, such as SiC, MgO, and aluminum for fusion reactor first wall, blanket, and shield applications. In addition to the advantage of very low radioactive inventory, it was found that the very low activation fusion reactor can also offer an adequate tritium breeding ratio and substantial amount of blanket nuclear heating as a conventional material structured reactor does. The most stringent design constraint found in a very low activation fusion reactor is the limited space available in the inboard region of a tokamak concept for shielding to protect the superconducting toroidal field coil. A reference design was developed which mitigates the constraint by adopting a removable tungsten shield design that retains the inboard dimensions and gives the same shield performance as the reference STARFIRE tokamak reactor design.. ...
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"SNAREs contribute to the specificity of membrane fusion". Neuron. 26 (2): 457-64. doi:10.1016/S0896-6273(00)81177-0. PMID ... integral component of membrane. • Golgi membrane. • trans-Golgi network membrane. • Golgi apparatus. • nucleoplasm. • cytosol. ... membrane. • plasma membrane. • SNARE complex. • early endosome. • phagocytic vesicle. • perinuclear region of cytoplasm. • ... vesicle fusion. • Golgi ribbon formation. • vesicle-mediated transport. • intracellular protein transport. • endocytic ...
Rab proteins are key in targeting the membrane; SNAP and SNARE proteins are key in the fusion event. ... Integral membrane proteins that stay embedded in the membrane as vesicles exit and bind to new membranes. ... The membranes of the ER are continuous with the outer nuclear membrane. The endoplasmic reticulum occurs in most types of ... The membrane of the rough endoplasmic reticulum forms large double membrane sheets that are located near, and continuous with, ...
Membrane Fusion Technique. Gulf Professional Publishing. July 1993. pp. 42-. ISBN 978-0-12-182122-7. Robert Blumenthal; Debi P ... "Dilation of the influenza hemagglutinin fusion pore revealed by the kinetics of individual cell-cell fusion events". Journal of ... "Sendai virus recruits cellular villin to remodel actin cytoskeleton during fusion with hepatocytes". Mol. Biol. Cell. 28 (26): ... "Initial stages of influenza hemagglutinin-induced cell fusion monitored simultaneously by two fluorescent events: cytoplasmic ...
This triggers fusion of the viral envelope with the cell membrane, allowing EBV to enter the B cell.[21] Human CD35, also known ... This triggers fusion of the viral envelope with the epithelial cell membrane, allowing EBV to enter the epithelial cell.[21] ... The viral three-part glycoprotein complexes of gHgL gp42 mediate B cell membrane fusion; although the two-part complexes of ... gHgL mediate epithelial cell membrane fusion. EBV that are made in the B cells have low numbers of gHgLgp42 complexes, because ...
Exocytosis involves the removal of substances through the fusion of the outer cell membrane and a vesicle membrane. An example ... Jahn, Reinhard; Südhof, Thomas C. (1999). "Membrane Fusion and Exocytosis". Annual Review of Biochemistry. 68 (1): 863-911. doi ... Jahn, Reinhard; Südhof, Thomas C. (1999). "Membrane Fusion and Exocytosis". Annual Review of Biochemistry. 68: 863-911. doi: ... Viruses enter cells through a form of endocytosis that involves their outer membrane fusing with the membrane of the cell. This ...
Fusion with the plasma membrane to release the core into the host cytoplasm. Early phase: early genes are transcribed in the ... or can acquire a second double membrane from trans-Golgi and bud as external enveloped virion (EEV)host receptors, which ...
Arienti G, Carlini E, Palmerini CA (January 1997). "Fusion of human sperm to prostasomes at acidic pH". The Journal of Membrane ... Carlini E, Palmerini CA, Cosmi EV, Arienti G (July 1997). "Fusion of sperm with prostasomes: effects on membrane fluidity". ... They possess an unusual lipid composition and a tight and highly ordered structure of their lipid bilayer membrane, resembling ... Minelli A, Moroni M, Martínez E, Mezzasoma I, Ronquist G (November 1998). "Occurrence of prostasome-like membrane vesicles in ...
Cevc, G; Richardsen, H (1993). "Lipid vesicles and membrane fusion". Advanced Drug Delivery Reviews. 38 (3): 207-232. doi: ... protons can pass through some membranes), the drug will also be neutralized, allowing it to freely pass through a membrane. ... To deliver the molecules to a site of action, the lipid bilayer can fuse with other bilayers such as the cell membrane, thus ... By preparing liposomes in a solution of DNA or drugs (which would normally be unable to diffuse through the membrane) they can ...
Fusion with the plasma membrane; ribonucleocapsid is released in the cytoplasm. Sequential transcription, viral mRNAs are ... The ribonucleocapsid binds to the matrix protein and buds via the host ESCRT complexes occurs at the plasma membrane host ...
Cholesterol is also necessary for the Alphavirus to undergo fusion. This fusion of the endosomal membrane to the viral envelope ... The E1 gene is a membrane fusion protein that is important in viral entry and release. Together E1 and E2 are the glycoproteins ... After being taken in through endocytosis, a low pH triggers a membrane fusion, which delivers the viral RNA genomes into the ... Kielian, Margaret; Chanel-Vos, Chantal; Liao, Maofu (2010-03-26). "Alphavirus Entry and Membrane Fusion". Viruses. 2 (4): 796- ...
... has also been used to study membrane fusion, an essential event for viral infection and a wide range of biological ... The development of models to predict the mechanisms of membrane fusion will assist in the scientific understanding of how to ... This fusion involves conformational changes of viral fusion proteins and protein docking, but the exact molecular mechanisms ... "Model systems for membrane fusion". Chemical Society Reviews (review). 40 (3): 1572-1585. doi:10.1039/c0cs00115e. PMID 21152599 ...
... membrane fusion protein (MFP), and outer membrane protein (OMP)[specify]. This secretion system transports various molecules, ... The vacuole is formed by the fusion of the cell membrane around the particle. A phagosome is a cellular compartment in which ... the formation of outer membrane vesicles.[8][9] Portions of the outer membrane pinch off, forming spherical structures made of ... Release of outer membrane vesicles. In addition to the use of the multiprotein complexes listed above, Gram-negative bacteria ...
... minimal machinery for membrane fusion". Cell. 92 (6): 759-72. doi:10.1016/s0092-8674(00)81404-x. PMID 9529252. Zemelman, BV; ... began working in the laboratory of James Rothman on SNARE proteins and their influence on the intracellular membrane fusion. ...
... minimal machinery for membrane fusion". Cell. 92 (6): 759-72. doi:10.1016/S0092-8674(00)81404-X. PMID 9529252. S2CID 5637048. ... SNARE proteins are the key components of the molecular machinery that drives fusion of membranes in exocytosis. Their function ... Bock JB, Scheller RH (October 1999). "SNARE proteins mediate lipid bilayer fusion". Proc. Natl. Acad. Sci. U.S.A. 96 (22): ... Fasshauer D, Sutton RB, Brunger AT, Jahn R (December 1998). "Conserved structural features of the synaptic fusion complex: ...
This protein may function in vesicle trafficking, membrane fusion, protein complex assembly and cell motility. Alternative ... The protein encoded by this gene is a type IV membrane protein. It is present in the plasma membrane and intracellular vesicles ... Vesicle-associated membrane protein-associated protein A is a protein that in humans is encoded by the VAPA gene. Together with ... Weir ML, Klip A, Trimble WS (Sep 1998). "Identification of a human homologue of the vesicle-associated membrane protein (VAMP)- ...
March 23 - Stanley Pons and Martin Fleischmann announce cold fusion at the University of Utah. The Oxford Database of Perinatal ... Discovery of the cystic fibrosis trans-membrane conductance regulator gene. The New Zealand Department of Conservation begins ...
Fusion of this lipid and the membrane lipid can occur, facilitating the entry of DNA. ... Another treatment method is the utilisation of electricity as the membrane-permeabilizing agent (electroporation or ... which make the cell membrane more permeable, leading to the uptake of the exogenous DNA. ...
Consequently, to this fusion so called lomasome-like accumulations are visible. These lomasome-like structures are membrane- ... At the basal septum vesicle fusion is observable. ...
Wilson DW, Whiteheart SW, Wiedmann M, Brunner M, Rothman JE (May 1992). "A multisubunit particle implicated in membrane fusion ... Hanson PI, Otto H, Barton N, Jahn R (July 1995). "The N-ethylmaleimide-sensitive fusion protein and alpha-SNAP induce a ... Hanson PI, Otto H, Barton N, Jahn R (July 1995). "The N-ethylmaleimide-sensitive fusion protein and alpha-SNAP induce a ... Hao JC, Salem N, Peng XR, Kelly RB, Bennett MK (March 1997). "Effect of mutations in vesicle-associated membrane protein (VAMP ...
... to the site of membrane fusion, thereby forming the 20S fusion complex. Alpha- and gamma-SNAP are found in a wide range of ... The 'SNARE hypothesis' is a model explaining the process of docking and fusion of vesicles to their target membranes. According ... Clary DO, Griff IC, Rothman JE (1990). "SNAPs, a family of NSF attachment proteins involved in intracellular membrane fusion in ... Wilson DW, Whiteheart SW, Wiedmann M, Brunner M, Rothman JE (1992). "A multisubunit particle implicated in membrane fusion". J ...
Fusion between the viral envelope (surrounding the viral capsid) and the cell membrane of the target cell is inhibited. This ... Umifenovir inhibits membrane fusion of influenza virus. Umifenovir prevents contact between the virus and target host cells. ... Boriskin YS, Leneva IA, Pécheur EI, Polyak SJ (2008). "Arbidol: a broad-spectrum antiviral compound that blocks viral fusion". ...
"Involvement of BNIP1 in apoptosis and endoplasmic reticulum membrane fusion". The EMBO Journal. 23 (16): 3216-26. doi:10.1038/ ... "Topological restriction of SNARE-dependent membrane fusion". Nature. 407 (6801): 194-8. doi:10.1038/35025076. PMID 11001058. ... membranes from brefeldin A-treated HepG2 cells identifies ERGIC-32, a new cycling protein that interacts with human Erv46". The ... "Implication of ZW10 in membrane trafficking between the endoplasmic reticulum and Golgi". The EMBO Journal. 23 (6): 1267-78. ...
The binding causes conformation changes and results in the membrane fusion between HIV and cell membrane. Active infection ...
Fusion of the plasma membranes of the sperm and egg are likely mediated by bindin. At the site of contact, fusion causes the ... Fusion between the oocyte plasma membranes and sperm follows and allows the sperm nucleus, the typical centriole, and atypical ... Oviparous animals producing eggs with thin tertiary membranes or no membranes at all, on the other hand, use external ... itself upon fusing with a single sperm cell and thereby changes its cell membrane to prevent fusion with other sperm. Zinc ...
Synaptobrevin is an integral V-SNARE necessary for vesicle fusion to membranes. The cleavage of synaptobrevin is the final ... on the neuronal membrane and contains a translocation domain which aids the movement of the protein across that membrane and ... The A-chain, a zinc endopeptidase, attacks the vesicle-associated membrane protein (VAMP). ... "Gangliosides in phospholipid bilayer membranes: interaction with tetanus toxin". Chemistry and physics of lipids. 81 (1): 21- ...
These glycoproteins allow for attachment and fusion of viral and cellular membranes. Fusion of these membranes allows the viral ... Weissenhorn W, Dessen A, Calder LJ, Harrison SC, Skehel JJ, Wiley DC (1999). "Structural basis for membrane fusion by enveloped ... These viruses also contain proteins on the surface of the cell membrane called glycoproteins. Type A and B have two ... effect of influenza virus glycoproteins on the membrane association of M1 protein". J. Virol. 74 (18): 8709-19. doi:10.1128/jvi ...
... vesicle-associated membrane protein 7) form an active SNARE complex for early macropinocytic compartment fusion in ... "SNAREs contribute to the specificity of membrane fusion". Neuron. 26 (2): 457-64. doi:10.1016/S0896-6273(00)81177-0. PMID ... Antonin W, Holroyd C, Fasshauer D, Pabst S, Von Mollard GF, Jahn R (December 2000). "A SNARE complex mediating fusion of late ... Antonin W, Holroyd C, Fasshauer D, Pabst S, Von Mollard GF, Jahn R (December 2000). "A SNARE complex mediating fusion of late ...
... vesicle-associated membrane protein 7) form an active SNARE complex for early macropinocytic compartment fusion in ... "SNAREs contribute to the specificity of membrane fusion". Neuron. 26 (2): 457-64. doi:10.1016/S0896-6273(00)81177-0. PMID ... These function as the machinery for the homotypic fusion of late endosomes. Model organisms have been used in the study of STX8 ... Antonin W, Holroyd C, Fasshauer D, Pabst S, Von Mollard GF, Jahn R (Dec 2000). "A SNARE complex mediating fusion of late ...
It is an essential component of the high affinity receptor for the general membrane fusion machinery and is an important ... Mollinedo F, Lazo PA (Feb 1997). "Identification of two isoforms of the vesicle-membrane fusion protein SNAP-23 in human ... form a complex which serves as a binding site for the general membrane fusion machinery. Synaptobrevin/VAMP and syntaxin are ... a component of the membrane fusion machinery". Molecular Biology of the Cell. 11 (10): 3485-94. doi:10.1091/mbc.11.10.3485. PMC ...
Two of SeV proteins: HA and F, after their binding directly to a cellular membrane, promote a cell-cell fusion, which leads to ... uses host cellular membrane lipid bilayer for viral capsid membrane formation. Binding to a host cell membrane of viral ... This cleavage promotes the fusion of the viral lipid envelope with the cell outer membrane. In the lipid envelope of the virus ... This cleavage triggers the fusion process of viral envelope and cell membrane, which promotes by cooperation of NH with the ...
... which is followed by fusion of the viral envelope with cellular membranes.[50] The virions taken up by the cell then travel to ... EBOV is thought to infect humans through contact with mucous membranes or skin breaks.[54] After infection, endothelial cells ( ... Virions bud off from the cell, gaining their envelopes from the cellular membrane from which they bud. The mature progeny ... Bleeding from mucous membranes or from sites of needle punctures has been reported in 40-50% of cases.[31] This may cause ...
Although the function of CD20 is unknown, it may play a role in Ca2+ influx across plasma membranes, maintaining intracellular ... fusion protein against VEGF (Aflibercept). *proapoptotic peptide against ANXA2 and prohibitin (Adipotide) ... The CD20 proteins are sticking out of the cell membrane, and rituximab, the Y-shaped antibody, is binding to the CD20 proteins. ...
Lang F, Alevizopoulos K, Stournaras C (2013). "Targeting membrane androgen receptors in tumors". Expert Opin. Ther. Targets. 17 ... Fusion of myoblasts generates myotubes, in a process linked to androgen receptor levels.[9] ... Androgens have also been found to signal through membrane androgen receptors, which are distinct from the classical nuclear ...
The balance between potassium and sodium is maintained by ion transporter proteins in the cell membrane.[231] The cell membrane ... Iron is especially common because it represents the minimum energy nuclide that can be made by fusion of helium in supernovae.[ ... as well as heats of fusion and vaporisation.[10]:75 In general, their densities increase when moving down the table, with the ... as well as heats of fusion and vaporisation.[10]:75 In general, their densities increase when moving down the table, with the ...
Hybrid Fusion-FISH[edit]. Hybrid Fusion FISH (HF-FISH) uses primary additive excitation/emission combination of fluorophores to ... The tissue sample is chemically treated in order to make the cell membranes permeable to the fluorescently tagged ... This variation is often called double-fusion FISH or D-FISH. In the opposite situation-where the absence of the secondary color ... Hybrid Fusion FISH enables highly multiplexed FISH applications that are targeted within clinical oncology panels. The ...
... thanks to hollow fiber membrane filters. Finally, a membrane degasifier (MD) removes radon dissolved in water, and the measured ... The energy of Sun comes from the nuclear fusion in its core where a helium atom and an electron neutrino are generated by 4 ... Photons, created by the nuclear fusion in the center of the Sun, take millions of years to reach the surface; on the other hand ... Mineguard is a spray-applied polyurethane membrane developed for use as a rock support system and radon gas barrier in the ...
Inside the endosome, the decreased pH induces the fusion of the endosomal membrane with the virus envelope. The capsid enters ... Receptor binding, as well as membrane fusion, are catalyzed by the protein E, which changes its conformation at low pH, causing ...
Therefore, macrophage membranes become susceptibile to bacterial infections.[11] Reproductive system[edit]. In experiments with ... Benzo[a]pyrene, showing the base pyrene ring and numbering and ring fusion locations according to IUPAC nomenclature of organic ... the molecular mechanism was uncovered as damage to the macrophage membrane's lipid raft integrity by decreasing membrane ...
Sir Arthur Eddington of Weston-super-Mare was the first to realise that nuclear fusion powered the Sun; at the 1920 British ... which in 2002 was the world's first production site of membrane electrode assemblies, and next door is Neptune, who make ...
... this fusion may make their membranes more rigid and better able to resist harsh environments.[112] For example, the lipids in ... No membrane-bound organelles (questioned[56]) or nucleus. No membrane-bound organelles or nucleus. Membrane-bound organelles ... MembranesEdit. Membrane structures. Top, an archaeal phospholipid: 1, isoprene chains; 2, ether linkages; 3, L-glycerol moiety ... They have membranes composed of glycerol-ether lipids, whereas bacteria and eukaryotes have membranes composed mainly of ...
early endosome membrane. • membrane. • bicellular tight junction. • Golgi membrane. • plasma membrane. • cell surface. • early ... "Wnt-independent activation of beta-catenin mediated by a Dkk1-Fz5 fusion protein". Biochem. Biophys. Res. Commun. 328 (2): 533- ... integral component of membrane. Biological process. • G-protein coupled receptor signaling pathway. • T cell differentiation in ... clathrin-coated endocytic vesicle membrane. • Golgi apparatus. • ...
... mucous membrane - Multicenter AIDS Cohort Study - multi-drug rescue therapy - multiple drug-resistant tuberculosis (MDR-TB) - ... fusion inhibitor - fusion mechanism - fusion peptide ...
Li X, Li S, Zhang M, Li X, Zhang X, Zhang W, Li C. (2010) Protective effects of a bacterially expressed NIF-KGF fusion protein ... Others modulate the activity of ion channels that control fluid transport across lung membranes or target surfactant, a ... Prolonged inflammation and destruction of pneumocytes leads to fibroblastic proliferation, hyaline membrane formation, tracheal ... the endothelium and the basement membrane of the alveolus. In the acute phase of ALI, there is increased permeability of this ...
CSAs have a high binding affinity for such membranes (including Lipid A[1]) and are able to rapidly disrupt the target ... Entry/fusion inhibitors. (Discovery and development). *gp41 (Enfuvirtide (ENF, T-20)). *CCR5 (Maraviroc (MVC) ... These compounds have a net positive charge that is electrostatically attracted to the negative-charged cell membranes of ... membranes leading to rapid cell death. While CSAs have a mechanism of action that is also seen in antimicrobial peptides, which ...
... while the ability of the retrovirus to enter the cell via membrane fusion is imparted by the membrane-anchored trans-membrane ... A retrovirus has a membrane containing glycoproteins, which are able to bind to a receptor protein on a host cell. There are ... Envelope: composed of lipids (obtained from the host plasma membrane during the budding process) as well as glycoprotein ... These pieces are then gathered together and are pinched off of the cell membrane as a new retrovirus (9). ...
Antibodies raised against bcd fusion proteins recognize a 55-57 kd doublet band in Western blots of extracts of 0-4 hr old ... this happens after each nucleus becomes wrapped with its own cell membrane). ...
... fusion of the mandibular symphysis was common in adapiforms,[88] notably Notharctus.[89] Also, several extinct giant lemurs ... and gums are tightly connected by a fold of mucous membrane called the philtrum, which runs from the tip of the nose to the ...
The first Keystone Symposia on autophagy was held in 2007 at Monterey.[26] In 2008, Carol A Mercer created a BHMT fusion ... Autophagy degrades damaged organelles, cell membranes and proteins, and the failure of autophagy is thought to be one of the ... which forms a double membrane known as an autophagosome, around the organelle marked for destruction.[28][31] The autophagosome ... Following the fusion LC3 is retained on the vesicle's inner side and degraded along with the cargo, while the LC3 molecules ...
external side of plasma membrane. • extracellular region. • plasma membrane. • membrane raft. • extracellular space. ... In an effort to localize the amino acid motif responsible for granule targeting, we constructed additional fusion proteins and ... membrane. • cell surface. • integral component of membrane. • recycling endosome. • intracellular. • integral component of ... positive regulation of membrane protein ectodomain proteolysis. • positive regulation of humoral immune response mediated by ...
Neutron reflectors, compressing the fissile core via implosion, fusion boosting, and "tamping", which slows the expansion of ... through semi-permeable membranes. This produces a slight separation between the molecules containing 235U and 238U. Throughout ... The 238U is not fissile but still fissionable by fusion neutrons. ... along with the fusion fuel lithium deuteride. For the secondary of a large nuclear weapon, the higher critical mass of less- ...
spoljašnja strana ćelijske membrane. • ćelijska površina. Biološki proces. • MAPK kaskada. • hemotaksa dendritske ćelije. • ... 2003). „The HIV Env-mediated fusion reaction". Biochim. Biophys. Acta. 1614 (1): 36-50. PMID 12873764. doi:10.1016/S0005-2736( ... and internalization in viral-cell fusion and as targets for entry inhibitors". Biochim. Biophys. Acta. 1614 (1): 51-61. PMID ...
Externally, a swelling called the genital tubercle appears above the cloacal membrane.[2] glans [18] ... Androgen induced development causes the elongation and differentiation of the phallus into a penis, a fusion of the urogenital ... The gonadal ridge continues to grow behind the developing peritoneal membrane. By week six, string-like cell congregations ... arises from an Indo dermal outgrowth of the urogenital sinus the bulbourethral glands develop from outgrowths in the membrane- ...
... rapidly destroys the lipoprotein membranes of microbes enveloped in phagosomes after fusion with lysosomes in ... of cell membranes of organisms toward which the peptide is active.[10] ...
The vRNA and viral core proteins leave the nucleus and enter this membrane protrusion (step 6). The mature virus buds off from ... "An open receptor-binding cavity of hemagglutinin-esterase-fusion glycoprotein from newly-identified Influenza D Virus: Basis ... One observer wrote, "One of the most striking of the complications was hemorrhage from mucous membranes, especially from the ... the cell in a sphere of host phospholipid membrane, acquiring hemagglutinin and neuraminidase with this membrane coat (step 7). ...
At sites of membrane budding or fusion, the membrane becomes or is highly curved. A major event in the budding of vesicles, ... The roles of lysoPA, PA, and DAG in promoting membrane curvature do not preclude a role in recruiting proteins to the membrane ... can cause membrane bending and destabilisation, playing a direct role in membrane fission simply by virtue of their biophysical ... the membrane while the surface headgroup remains unchanged. This can result in a more negative membrane curvature. Researchers ...
... dissociates from E2 and initiates membrane fusion that allows the release of nucleocapsids into the host cytoplasm, promoting ... E1 contains a fusion peptide which, when exposed to the acidity of the endosome in eukaryotic cells, ...
Discoveries revealing the universal molecular machinery that orchestrates the budding and fusion of membrane vesicles-a process ...
Envelope fusion with the plasma membrane of the host cell causes separation of the nucleocapsid from viral DNA and proteins. ... gB, gD, gH, and gL proteins allow for fusion of the cell and envelope, and are necessary for survival. Entrance to host cells ... DVH-1 replicates in the mucus membranes of bird's esophagus and cloaca, the two primary entrances of the virus. The means of ... mucous membranes, trachea, syrinx and intestine are pathognomonic for DEV. Diagnosis can also be confirmed with presence of ...
... in the fusion of egg cell and sperm. Such fused cells are also involved in metazoan membranes such as those that prevent ... A membrane would then form around each nucleus (and the cellular space and organelles occupied in the space), thereby resulting ... The fact that all known cell fusion molecules are viral in origin suggests that they have been vitally important to the inter- ... Without the ability of cellular fusion, colonies could have formed, but anything even as complex as a sponge would not have ...
Eukaryotic cells contain membrane-bound organelles that can undergo fusion with each other in a regulated manner. The widely ... This is the first report of the reconstitution of membrane fusion efficiently and under physiological conditions and also ... Although SNAREs are capable of fusing vesicles with high specificity, fusion reactions with native SNAREs alone are inefficient ... This technical tour de force allows the study of how cells orchestrate and perform such fusion events. ...
See Letter p.634 Membrane fusion affects many cellular events and is essential for cell survival. It is thought that the ... providing mechanical energy to distort membranes through a hemifusion intermediate to form a fusion pore. But Andreas Mayer and ... They find that, in yeast cells, tether proteins are also essential for the transition from the hemifused state to the fusion ... It emerges that proteins that tether fusing structures together also decrease the energy needed for the final fusion step. ...
2012) Cell-cell membrane fusion induced by p15 fusion-associated small transmembrane (FAST) protein requires a novel fusion ... Membrane Fusion as the Last Step in Lysis.. Here we have presented results that phage spanins can mediate efficient membrane ... Mechanism of Membrane Fusion.. The results presented here allow inferences to be drawn about the mechanism of IM-OM fusion. ... This suggests that these alleles are defective in a final step in membrane fusion, beyond bringing the target membranes into ...
Flavivirus structure and membrane fusion.. Heinz FX1, Allison SL.. Author information. 1. Institute of Virology, University of ...
This is the first demonstration of self-contact-induced membrane fusion in mammalian cells and that membrane fusion may be an ... Both cell lines had a comparable number of membrane fusion. Quantitative analysis of fusion displayed as mean fusion/pillar ± ... also had reduced membrane fusion compared with wild type after 6 h, whereas having comparable membrane fusion after 48 h (Fig. ... Whereas both membrane fusion (in exocytosis or cell fusion) and fission (in endocytic processes) require initial membrane ...
Viral and cellular membrane fusion events are mediated by fusion proteins or fusion machines. Viral fusion proteins share ... Fusion pores develop during and intracellular fusion events suggesting similar mechanisms for many, if not all, fusion events. ... Components of intracellular fusion machines are utilized in multiple membrane trafficking events and are conserved through ... At least one protein involved in a cell-cell fusion reaction resembles viral fusion proteins. ...
Membrane transport: Take your fusion partners.. Clague MJ1.. Author information. 1. Physiological Laboratory, University of ... that mediates the fusion reaction. The tethering protein is recruited to membranes by a Rab family GTPase. ... Recent studies of how vesicles are targeted to fuse with specific membranes inside cells highlight a role for extended coiled- ... coil proteins in tethering partner membranes prior to formation of the SNARE complex ...
Purchase GTPases Regulating Membrane Targeting and Fusion, Volume 403 - 1st Edition. Print Book & E-Book. ISBN 9780121828080, ... GTPases Regulating Membrane Targeting and Fusion, Volume 403 1st Edition. 0 star rating Write a review ... and fusion components (SNAREs) that control membrane targeting and fusion. During the last 3 years the field has virtually ... This volume of Methods in Enzymology, GTPases Regulating Membrane Targeting and Fusion, provides a wealth of new concepts, ...
In studies of influenza virus, we are focused on understanding the process of membrane fusion and fusion protein activation. In ... membrane fusion, genome expulsion, assembly, and cell egress. The changes often involve concerted changes among hundreds of ... protein components and in the case of enveloped viruses, membranes as well. From this perspective, virions are intricate, nano- ...
... fusion model »membrane fusion model »membrane structure »single protein »vesicles ... fusion model , membrane fusion model , membrane structure , single protein , vesicles ... Membrane fusion a mystery no more. 25.01.2012. The many factors that contribute to how cells communicate and function at the ... Accepter SNARE proteins then form, allowing fusion with another vesicle membrane. How this mechanistically happens has been ...
The process of membrane fusion is fundamental to cellular organization and has been the focus of a vast literature. Südhof and ... T. C. Südhof, J. E. Rothman, Membrane fusion: Grappling with SNARE and SM proteins. Science 323, 474-477 (2009). [Abstract] [ ... Two further papers also shed light on complexins role in regulating SNARE-mediated membrane fusion. Giraudo et al. show that a ... The protein complexin may act as a force-transferring switch during membrane fusion. ...
The protein complexin may act as a force-transferring switch during membrane fusion. ... The protein complexin may act as a force-transferring switch during membrane fusion. ...
... fusion of the outer leaflets (hemifusion), opening and expansion of the fusion neck and finally full fusion. In our study, we ... It consists of consecutive steps including docking of the two bilayers, membrane destabilization, ... investigated the fusion between small cationic liposomes (~100 nm) and giant vesicles (tens of microns in diameter) containing ... Membrane fusion is a ubiquitous process, essential for cellular development, communication, and drug delivery. ...
The widely accepted model for membrane fusion suggests that there is an intermediate state in which the two contacting ... The observation of the stalk structure supports the stalk hypothesis for membrane fusion and enables the measurement of these ... efforts have been made to estimate the free energy for such a state in order to understand the functionality of membrane fusion ... phospholipid that contains a structure similar to the commonly postulated interbilayer state that is crucial to membrane fusion ...
Kielian will discuss her studies on the mechanisms associated with membrane fusion in alphaviruses and flaviviruses, and the ... Virus-Membrane Fusion: Mechanisms and Inhibition. Wednesday, April 19, 2006. The New York Academy of Sciences ... During fusion these class II viral fusion proteins trimerize and refold to form hairpin-like structures with the domain III and ... Alphaviruses and flaviviruses infect cells through low pH-dependent membrane fusion reactions mediated by their structurally ...
... Doron Kabaso,1,2 Ana I. Calejo,3 ... Fusion Pore Diameter Regulation by Cations Modulating Local Membrane Anisotropy, Doron Kabaso, Ana I. Calejo, Jernej ... "Fusion Pore Diameter Regulation by Cations Modulating Local Membrane Anisotropy"," The Scientific World Journal, vol. 2012, ...
Why exactly does the cell membrane become more fluid in higher temperatures than lower? Does it have anything to do with the ...
Membrane fusion is essential in several cellular processes in the existence of eukaryotic cells such as cellular trafficking, ... Membrane fusion Bending energy Void space Membrane curvature Depth-dependent membrane ordering Fusion peptide ... Membrane fusion proceeds in model membranes as well as biological membranes through the rearrangement of lipids. The stalk ... Evolution of lipidic structures during model membrane fusion and the relation of this process to cell membrane fusion. ...
The Principle of Membrane Fusion in the Cell: Lecture Slides. Pdf 7.49 MB. Copyright © James E. Rothman ... James E. Rothman - Nobel Lecture: The Principle of Membrane Fusion in the Cell ...
Max Planck scientists develop new methods for the controlled initiation of membrane fusion and its observation with high ... The process of membrane fusion is essential for the structure and dynamics of all cells in our bodies. Fusion is indispensable ... Close proximity of the vesicle membranes was achieved by displacing these micropipettes. Membrane fusion was subsequently ... to initiate the fusion of their membranes in a controlled manner and to study the subsequent fusion dynamics with high temporal ...
This membrane protein imports 3 Na ions and exports 2 K ions at the cost of hydrolyzing 1 molecule of ATP. What this means is ... Is there any reason,resting membrane potential is cca -70mV?because teacher asked us today,and it was not enough for him to say ... First, consider what generates the membrane potential- the battery of a cell. For mammalian cells, this is the Na-K ATPase ... For ions with a single excess charge, a concentration gradient of 1:10 across a membrane at 30C provides a 60mV potential ...
Removal of envelope cholesterol greatly reduced virion fusion activity as measured by fusion-from-without, suggesting that ... suggesting that virion cholesterol is critical for the step of membrane fusion. MβCD-treatment of HSV-1 did not reduce viral ... The pre-fusion form of gB present in the HSV-1 envelope undergoes conformational changes in response to mildly acidic pH. These ... The pre-fusion form of gB present in the HSV-1 envelope undergoes conformational changes in response to mildly acidic pH. These ...
A model system for membrane fusion, inspired by SNARE proteins and based on two complementary lipopeptides CPnE4 and CPnK4, has ... A model system for membrane fusion, inspired by SNARE proteins and based on two complementary lipopeptides CPnE4 and CPnK4, has ... Distinct roles of SNARE-mimicking lipopeptides during initial steps of membrane fusion A. Koukalová, Š. Pokorná, A. L. Boyle, N ... which enables fusion. Whereas E4 is exposed to the bulk and solely promotes membrane binding of CPnK4, K4 loops back to the ...
HA also mediates membrane fusion between the virus and a cell, which is the first critical step during infection. Traditional ... Visualizing Influenza Virus Membrane Fusion: Inhibition and Kinetics. Doctoral dissertation, Harvard University. ... Virus particles are labeled to visualize lipid mixing between a virus and a target membrane formed upon a glass or polymer ... techniques to study infection neutralization by antibodies or the membrane fusion process rely on ensemble measurements, ...
... beginning with fusion and fission of lipid bilayers, with reviews focused on hemifusion... ... This volume of Current Topics in Membranes focuses on Membrane Fusion, ... This volume of Current Topics in Membranes focuses on Membrane Fusion, beginning with fusion and fission of lipid bilayers, ... Intracellular fusion. - C2 domains and membrane fusion Sascha Martens and Harvey T. McMahon. - Chasing the trails of SNAREs and ...
Interbilayer forces in membrane fusion Viral membrane fusion proteins Classification of viral fusion proteins in TCDB database ... not to be confused with chimeric or fusion proteins) are proteins that cause fusion of biological membranes. Membrane fusion is ... which encode products involved in driving membrane fusion. While adult somatic cells do not typically undergo membrane fusion ... Domain 1 contains the catalytic site for membrane fusion. Class IV are the smallest fusion proteins. They are also called ...
Membrane and actin reorganization in electropulse-induced cell fusion Günther Gerisch, Mary Ecke, Ralph Neujahr, Jana Prassler ... Vesicular PtdIns(3,4,5)P3 and Rab7 are key effectors of sea urchin zygote nuclear membrane fusion Marta G. Lete, Richard D. ... Summary: We present a new methodology to reconstitute proteins on membranes with complex geometry by means of vesicle fusion, ... P3 directly interact during the membrane fusion process. ... Visualization of the moment of mouse sperm-egg fusion and ...
... We introduce a novel assay for membrane fusion of solid supported membranes on silica beads and on coverslips ... The probability of fusion is controlled by the membrane tension on the particle. We show that the progression of fusion can be ... Florin, E.-L. Direct observation of intermediate states in model membrane fusion. Scientific Reports 6, 23691; doi:10.1038/ ... We were able to observe all fusion intermediates including transient fusion, formation of a stalk, hemifusion and the ...
Membrane fusion is the critical step for infectious cell penetration by enveloped viruses. We have previously used single- ... Distinct functional determinants of influenza hemagglutinin-mediated membrane fusion. Author: Ivanovic, Tijana; Harrison, ... Distinct functional determinants of influenza hemagglutinin-mediated membrane fusion. DSpace/Manakin Repository. * DASH Home ... "Distinct functional determinants of influenza hemagglutinin-mediated membrane fusion." eLife 4 (1): e11009. doi:10.7554/eLife. ...
  • Intracellular membrane fusion has been mimicked in vitro using a mix of 17 purified proteins and lipid bilayers. (nature.com)
  • About half of all biological processes involve membrane proteins, which must be delivered, and eventually removed, with great accuracy to regulate the constancy of structural identity. (nature.com)
  • 2 describe an enormous technical accomplishment - the self-assembly of 17 individual purified proteins into a fusion 'machine' whose activity and regulation recapitulate those of membrane fusion in an intact cell. (nature.com)
  • These include the SNARE family of membrane proteins and the Rab proteins, a subfamily of the Ras superfamily of GTPase enzymes. (nature.com)
  • The membrane-bound SNARE proteins link the two membranes destined for fusion. (nature.com)
  • They do this by interacting with partner SNARE proteins on the opposing membrane to form a stable, four-coiled bundle consisting of helices from several individual SNARE proteins 4 ( Fig. 1 ). (nature.com)
  • Figure 1: Proteins work together to mediate endosomal membrane fusion. (nature.com)
  • 2 show that two protein systems, a Rab GTPase (Rab5) and the SNARE proteins, combine synergistically to drive endosomal fusion. (nature.com)
  • SNARE complexes are structurally similar to viral envelope proteins known to catalyse membrane fusion 6 , so a paradigm emerged casting these rod-shaped helical bundles into the central role of 'minimal fusion machine', with all other proteins assigned to supporting roles such as regulation of the SNARE complex 7 . (nature.com)
  • However, direct tests comparing the contributions of SNAREs alone with SNAREs plus all the other proteins essential for fusion have not been performed because of the complexities of assembling microgram quantities of membrane proteins in defined lipid environments together with other fragile purified proteins - requirements that stretch the limits of current biochemical technologies. (nature.com)
  • It emerges that proteins that tether fusing structures together also decrease the energy needed for the final fusion step. (nature.com)
  • SNAREs are a group of membrane proteins present on the surface of vesicles and organelles. (nature.com)
  • However, SNARE proteins have only a small cytoplasmic domain that is probably too short to bring a vesicle close to the organelle that is its fusion target (although SNARE proteins are sufficient to drive membrane fusion in reconstituted cell-free in vitro systems 3 ). (nature.com)
  • Tethers determine whether a potential fusion interaction should occur, through recognition of specific proteins found on a vesicle surface, such as Rab proteins or coat proteins 4 . (nature.com)
  • This is accomplished by spanins, which are phage-encoded proteins that connect the cytoplasmic membrane (inner membrane, IM) and the OM. (pnas.org)
  • The infection cycle suddenly terminates when the S105 holins, small membrane proteins encoded by gene S , are redistributed into large 2D foci, resulting in the formation of μm-scale holes in the cytoplasmic membrane ( 3 ). (pnas.org)
  • When the plasma membranes of neighboring cells physically interact, cell-cell adhesion proteins engage and autonomously and rapidly develop into mature cell junctions. (pnas.org)
  • Viral and cellular membrane fusion events are mediated by fusion proteins or fusion machines. (sciencemag.org)
  • Viral fusion proteins share important characteristics, notably a fusion peptide within a transmembrane-anchored polypeptide chain. (sciencemag.org)
  • At least one protein involved in a cell-cell fusion reaction resembles viral fusion proteins. (sciencemag.org)
  • Recent studies of how vesicles are targeted to fuse with specific membranes inside cells highlight a role for extended coiled-coil proteins in tethering partner membranes prior to formation of the 'SNARE complex' that mediates the fusion reaction. (nih.gov)
  • This volume of Methods in Enzymology , GTPases Regulating Membrane Targeting and Fusion , provides a wealth of new concepts, approaches and tools to study Rab proteins in the test tube and in living cells that will be of strong benefit to both established laboratories and new investigators in the field to elucidate Rab GTPase function in cellular development, differentiation and proliferation. (elsevier.com)
  • That fusion process is, in part, mediated through SNARE proteins that bring the vesicles together. (innovations-report.com)
  • In the classic model, it was believed SNARE proteins originating from two opposing membranes are somehow activated and separated into single proteins. (innovations-report.com)
  • Accepter SNARE proteins then form, allowing fusion with another vesicle membrane. (innovations-report.com)
  • Researchers found that when this tethering factor was removed, the SNARE proteins were unstable and there was no fusion. (innovations-report.com)
  • Südhof and Rothman review the role of so-called SNARE and SM proteins in membrane fusion and present a hypothesis for how they are regulated by other proteins, termed grapples, exemplified by complexin. (sciencemag.org)
  • T. C. Südhof, J. E. Rothman, Membrane fusion: Grappling with SNARE and SM proteins. (sciencemag.org)
  • Many efforts have been made to estimate the free energy for such a state in order to understand the functionality of membrane fusion proteins and to define key parameters in energy estimates. (sciencemag.org)
  • In addition, the mechanism by which proteins and peptides reduce the activation energy for stalk and pore formation is not yet clear though there are several propositions on how they catalyze membrane fusion. (springer.com)
  • Campelo F, McMahon HT, Kozlov MM (2008) The hydrophobic insertion mechanism of membrane curvature generation by proteins. (springer.com)
  • A model system for membrane fusion, inspired by SNARE proteins and based on two complementary lipopeptides CP n E 4 and CP n K 4 , has been recently developed. (rsc.org)
  • Membrane fusion proteins (not to be confused with chimeric or fusion proteins) are proteins that cause fusion of biological membranes. (wikipedia.org)
  • Fusion proteins can originate from genes encoded by infectious enveloped viruses, ancient retroviruses integrated into the host genome, or solely by the host genome. (wikipedia.org)
  • Post-transcriptional modifications made to the fusion proteins by the host can drastically affect fusogenicity, namely addition and modification of glycans and acetyl groups. (wikipedia.org)
  • Vesicle fusion events involved in neurotransmitter trafficking also relies on the catalytic activity of fusion proteins. (wikipedia.org)
  • The SNARE family include bona fide eukaryotic fusion proteins. (wikipedia.org)
  • They are domesticated viral class I fusion proteins. (wikipedia.org)
  • Enveloped viruses readily overcome the thermodynamic barrier of merging two plasma membranes by storing kinetic energy in fusion (F) proteins. (wikipedia.org)
  • F proteins can be independently expressed on host cell surfaces which can either (1) drive the infected cell to fuse with neighboring cells, forming a syncytium, or (2) be incorporated into a budding virion from the infected cell which leads to the full emancipation of plasma membrane from the host cell. (wikipedia.org)
  • Some F components solely drive fusion while a subset of F proteins can interact with host factors. (wikipedia.org)
  • There are four groups of F proteins categorized by their mechanism of fusion. (wikipedia.org)
  • Class I fusion proteins resemble influenzavirus hemagluttinin in their structure. (wikipedia.org)
  • Class III fusion proteins are distinct from I and II. (wikipedia.org)
  • Class IV are the smallest fusion proteins. (wikipedia.org)
  • They are also called fusion-associated small transmembrane (FAST) proteins and are most often associated with non-enveloped reoviruses. (wikipedia.org)
  • Interbilayer forces in membrane fusion Viral membrane fusion proteins Classification of viral fusion proteins in TCDB database Klapper R, Stute C, Schomaker O, Strasser T, Janning W, Renkawitz-Pohl R, Holz A (January 2002). (wikipedia.org)
  • We present a new methodology to reconstitute proteins on membranes with complex geometry by means of vesicle fusion, unveiling a putative novel function of CHMP2B as a diffusion barrier in dendritic spines. (biologists.org)
  • Tetraspanins comprise a family of integral proteins that span the membrane 4-fold and establish specialized microdomains based on noncovalent protein-protein interactions ( 13 ). (jimmunol.org)
  • While well-established methods for structure determination such as X-ray crystallography have provided detailed structures of fusion proteins in the pre- and post-fusion fusion states, to understand mechanistically how these fusion glycoproteins perform their structural calisthenics and drive membrane fusion requires new analytical approaches that enable dynamic intermediate states to be probed. (mdpi.com)
  • All known viral fusion proteins or protein complexes have common features. (asm.org)
  • Many viral fusion proteins are tight complexes of two glycoprotein subunits that confer binding as well as fusion activity, and many are made as larger precursors which require proteolytic activation of their fusogenic potential ( 16 ). (asm.org)
  • Virus mutants lacking glycoprotein gB, gD, gH, or gL are unable to penetrate target cells, a defect which can be at least partially overcome by treatment with an artificial fusogen, polyethylene glycol, indicating that these proteins are involved in the fusion process (reviewed in references 27 and 37 ). (asm.org)
  • Glycoprotein gB, a highly conserved protein present in all subfamilies of the herpesviruses, is one of the most abundant proteins in the viral membrane and exhibits many features described for fusion proteins: it is a homodimeric type I N-glycosylated membrane protein, which in most herpesviruses is cleaved by a cellular protease into two disulfide-linked subunits ( 33 ). (asm.org)
  • The fusion of lipid membranes is central to biological functions like inter-cellular transport and signaling and is coordinated by proteins of the soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) superfamily. (aps.org)
  • We utilize molecular dynamics simulations to demonstrate that gold nanoparticles functionalized with a mixed-monolayer of hydrophobic and hydrophilic alkanethiol ligands can act as synthetic analogues of these fusion proteins and mediate lipid membrane fusion by catalyzing the formation of a toroidal stalk between adjacent membranes and enabling the formation of a fusion pore upon influx of Ca$^{2+}$ into the exterior solvent. (aps.org)
  • Fusion of biological membranes is mediated by proteins. (wikipedia.org)
  • Due to their long range nature, they are responsible for rapid coagulation of hydrophobic particles in water and play important roles in various biological phenomena including folding and stabilization of macromolecules such as proteins and fusion of cell membranes. (wikipedia.org)
  • Membranes isolated from COS-7 cells transfected with either FLAG-tagged P /rds or HA-tagged ROM-1 or both proteins were assayed for their ability to merge with fluorescently labeled OS plasma membrane (PM). Such membrane merger is one measure of membrane fusogenicity. (ovid.com)
  • The highest percent fusion was observed when the proteins were co-expressed. (ovid.com)
  • The SNARE (soluble N -ethylmaleimide-sensitive fusion protein attachment receptor) proteins are required for vesicle fusion events in both constitutive and Ca 2+ -regulated vesicle transport pathways ( Jahn and Scheller, 2006 ). (jneurosci.org)
  • A key element of membrane fusion reactions in biology is the involvement of specific fusion proteins. (nih.gov)
  • In many viruses, the proteins that mediate membrane fusion usually exist as homotrimers. (nih.gov)
  • The SEC18 gene product is 48% identical to mammalian NSF (N-ethylmaleimide-sensitive fusion protein), and both proteins encode cytoplasmic ATPases which are essential for membrane traffic in yeast and mammalian cells, respectively. (nih.gov)
  • through its interaction with SNAPs (soluble NSF attachment proteins), NSF can associate with SNAP receptors (SNAREs) on intracellular membranes, forming 20S complexes. (nih.gov)
  • Intra- and inter-cellular membrane fusion processes are all mediated by specialized membrane fusion proteins and baker's yeast Saccharomyces cerevisiae has been an invaluable model system to study these fusion events. (rice.edu)
  • Intracellular fusion in yeast is mediated by a large family of proteins named SNAREs, however, the molecular machinery mediating intercellular membrane fusion between yeast haploid cells remains unknown. (rice.edu)
  • I was able to isolate post-Golgi vesicles from yeast cells stimulated with mating pheromone and find yeast intercellular fusion related proteins associated with these vesicles. (rice.edu)
  • For example, the proportion of hemagglutinins on a virus particle that insert into the cell membrane affects how fast fusion occurs and how sensitive the virus is to attack by host immune-system proteins called antibodies. (elifesciences.org)
  • The influenza hemagglutin (HA) is the best studied and most thoroughly characterized of the viral fusion proteins. (elifesciences.org)
  • The information we obtained could help in future studies of membrane-acting drugs, membrane-associated proteins, and peptides in a membrane complex. (phys.org)
  • Dozens of proteins, originating from both the cytoplasm and membranes are involved. (booktopia.com.au)
  • In this respect interfering proteins should be considered as preventing undesirable and unnecessary fusion and eventually directing the biological membrane fusion process (when, where, how, and overcoming the activation energy). (booktopia.com.au)
  • 1998). While SNAREs combine in specific combinations to drive highly specific membrane fusion, it is clear that SNARE proteins do not act independently to regulate the entire fusion process. (rice.edu)
  • Sec1 proteins are likely to be critical players in membrane trafficking. (rice.edu)
  • Concentration dependent stimulation of membrane fusion is observed when Sec1p is associated with the SNARE proteins. (rice.edu)
  • Membrane Fusion Proteins" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus, MeSH (Medical Subject Headings) . (umassmed.edu)
  • This graph shows the total number of publications written about "Membrane Fusion Proteins" by people in this website by year, and whether "Membrane Fusion Proteins" was a major or minor topic of these publications. (umassmed.edu)
  • Below are the most recent publications written about "Membrane Fusion Proteins" by people in Profiles. (umassmed.edu)
  • Exchange of lipids, metabolites or proteins across the lipid bilayer can occur through integral membrane proteins - as demonstrated for peroxisomes, mitochondria or chloroplasts. (biologists.org)
  • Generally, vesicle formation requires a conserved set of coat proteins that bind to cargo and induce membrane curvature. (biologists.org)
  • The binding and fusion processes are mediated by the spike proteins in the envelope of the virus particle and usually involve a series of conformational changes in these proteins. (asm.org)
  • This technique expands the scope of force spectroscopy to processes at and between lipid bilayers, like the formation of coiled coils between SNARE (soluble N-ethylmaleimide-sensitive factor attachment receptor) proteins as well as subsequent membrane fusion. (springer.com)
  • To this end, two solid-supported membranes equipped with SNARE proteins or fusion peptides are separately deposited on a flat glassy surface and on a micrometer glass sphere attached to the end of a tipless AFM cantilever. (springer.com)
  • In this chapter we describe the preparation of membrane-coated colloidal probes attached to AFM cantilevers, experimental procedures, and necessary data analysis to perform membrane probe spectroscopy in the presence of fusogenic peptides or proteins. (springer.com)
  • To gain insight into the atomistic details of membrane fusion induced by fusogenic peptides, molecular dynamic simulations of synthetic peptides, derived from viral fusion proteins, contained in lipid bilayers were performed. (scirp.org)
  • Tamm, L.K., Crane, J. and Kiessling, V. (2003) Mem-brane fusion: A structural perspective on the interplay of lipids and proteins. (scirp.org)
  • SNAREs, tethers and SM proteins: how to overcome the final barriers to membrane fusion? (portlandpress.com)
  • At first sight, fusion proteins such as SNARE complexes and viral fusion proteins appear to act as nano-machines, which mechanically transduce force to the membranes and thereby overcome the free energy barriers [ 2 , 3 ]. (portlandpress.com)
  • Whether fusion proteins additionally alter the free energy landscape of the fusion reaction via catalytic roles is less obvious. (portlandpress.com)
  • These results indicate that nuclear envelope assembly is mediated by a subset of approximately 70-nM-diam vesicles which bind to chromatin sites spaced 100 kb apart and that fusion of these vesicles is regulated by membrane-associated GTP-binding proteins. (rupress.org)
  • The vertex microdomain, enriched in fusogenic lipids and proteins, is the origin of fusion where the outer membranes are joined. (illinois.edu)
  • This project sought to identify the role of ABC transporters in membrane fusion as regulators of fusogenic proteins and lipids and their role in the mechanism of remodeling the membrane bilayer as lipid translocators. (illinois.edu)
  • The conserved, fusion-inducing conformational rearrangements these proteins undergo when exposed to reduced pH, from a pre-fusion dimer to a post-fusion trimer, offer an opportunity to exploit the common structural features of all flavivirus E proteins to find viral entry inhibitors ( Figure 1 ). (elifesciences.org)
  • Furthermore, although paramyxovirus attachment proteins may fold into very similar "pre-receptor-bound" conformational states, the presence of the "spacer" module in the stalk emerges as a key determinant leading to distinct mechanisms of membrane fusion triggering. (prolekare.cz)
  • Both proteins tightly associate to execute membrane fusion at neutral pH. (prolekare.cz)
  • As with other class I membrane fusion proteins, S is post-translationally cleaved, in this case by furin, into S1 and S2 components that remain associated following cleavage8-10. (crick.ac.uk)
  • Genetically encoded spy ppeptide fusion system to detect plasma membrane-localized proteins in vivo. (ucsb.edu)
  • Membrane proteins are the main gatekeepers of cellular state, especially in neurons, serving either to maintain homeostasis or instruct response to synaptic input or other external signals. (ucsb.edu)
  • We show that the genetically encoded, covalent binding SpyTag and SpyCatcher pair from the Streptococcus pyogenes fibronectin-binding protein FbaB can selectively label membrane-localized proteins in living cells in culture and in vivo in Caenorhabditis elegans. (ucsb.edu)
  • For many viruses, one or two proteins allow cell attachment and entry, which occurs through the plasma membrane or following endocytosis at low pH. (prolekare.cz)
  • four proteins mediate cell attachment and twelve that are associated in a membrane complex and conserved in all poxviruses are dedicated to entry. (prolekare.cz)
  • The aim of the present study was to determine the roles of cellular and viral proteins in initial stages of entry, specifically fusion of the membranes of the mature virion and cell. (prolekare.cz)
  • To determine the role of viral proteins, virions lacking individual membrane components were purified from cells infected with members of a panel of ten conditional-lethal inducible mutants. (prolekare.cz)
  • Taken together, these results suggested a 2-step entry model and implicated an unprecedented number of viral proteins and cellular components involved in signaling and actin rearrangement for initiation of virus-cell membrane fusion during poxvirus entry. (prolekare.cz)
  • 15_17_Vesicles_bud.jpg Vesicles bud from one membrane and fuse with another, carrying membrane components and soluble proteins between cellular compartments. (coursehero.com)
  • 15_21_membr_fusion.jpg SNARE proteins play a central role in membrane fusion. (coursehero.com)
  • Binding of NSF to Golgi membranes is known to require an integral membrane receptor and one or more members of a family of related soluble NSF attachment proteins (alpha-, beta-, and gamma-SNAPs). (rupress.org)
  • Sec1 proteins are critical players in membrane trafficking, yet their precise role remains unknown. (rupress.org)
  • This seemingly simple membrane fusion event is responsible for a multitude of diverse biochemical processes such as the secretion of hormones, release of neurotransmitters, and the localization of a host of receptor proteins and most other integral membrane proteins to the plasma membrane. (rupress.org)
  • Biological membrane fusion relies on proteins to drive the fusion reaction. (rupress.org)
  • SNARE proteins are operationally divided into two groups: those found primarily on the transport vesicle SNARE (v-SNARE), and those found primarily on the target membrane SNARE (t-SNARE). (rupress.org)
  • Although membrane fusion events are essential for the formation of thylakoid membranes, proteins involved in membrane fusion have yet to be identified in photosynthetic cells or organelles. (au.dk)
  • We propose that IM30 establishes contacts between internal membrane sites and promotes fusion to enable regulated exchange of proteins and/or lipids in cyanobacteria and chloroplasts. (au.dk)
  • The plasma membrane proteins Prm1 and Fig1 ascertain fidelity of membrane fusion during yeast mating. (ucsf.edu)
  • Response to drugs that inhibit lipid synthesis or interfere with lipids is different in wild-type, prm1Δ, and dni1Δ strains, suggesting that membrane structure/organization/dynamics is different in all these strains and that Prm1p and the Dni proteins exert some functions required to guarantee correct membrane organization that are critical for cell fusion. (ox.ac.uk)
  • The structures confirm the prediction that Gc is a class II fusion protein, containing the characteristic β-sheet rich domains termed I, II and III as initially identified in the fusion proteins of arboviruses such as alpha- and flaviviruses. (pasteur.fr)
  • Furthermore, the structure reveals that hantavirus Gc has an additional N-terminal "tail" that is crucial in stabilizing the post-fusion trimer, accompanying the swapping of domain III in the quaternary arrangement of the trimer as compared to the standard class II fusion proteins. (pasteur.fr)
  • Although SNARE complex disassembly and assembly might be thought to be opposing reactions, the proteins promoting disassembly (Sec17p/Sec18p) and assembly (the HOPS complex) work synergistically to support fusion. (embopress.org)
  • Other proteins cooperate with the SNAREs to achieve fusion. (embopress.org)
  • Furthermore, there are no structures of the intermediate forms of the membrane fusion proteins that are believed to mediate the viral and cell membrane fusion reaction. (embopress.org)
  • Rz and Rz1 are a type II integral membrane protein ( N -in, C-out) and an outer membrane (OM) lipoprotein, respectively ( 9 ⇓ - 11 ). (pnas.org)
  • The efficiency of fusion depends on the expression of the cell-cell adhesion molecule E-cadherin and the contractile state of the cell regulated through Rho-associated protein kinase. (pnas.org)
  • Additionally, Rho-associated protein kinase inhibition decreases self-contact-induced membrane fusion of epithelial cells, suggesting that this fusion may be mechanically regulated through the actin-myosin network. (pnas.org)
  • The tethering protein is recruited to membranes by a Rab family GTPase. (nih.gov)
  • They are intimately involved in vesicle targeting and fusion in both the endocytic and exocytic pathways and direct the assembly and disassembly of protein complexes that include regulators (GEFs and GAPs), effectors (tethers/motors) and fusion components (SNAREs) that control membrane targeting and fusion. (elsevier.com)
  • The changes often involve concerted changes among hundreds of protein components and in the case of enveloped viruses, membranes as well. (washington.edu)
  • In studies of influenza virus, we are focused on understanding the process of membrane fusion and fusion protein activation. (washington.edu)
  • The protein complexin may act as a force-transferring switch during membrane fusion. (sciencemag.org)
  • This membrane protein imports 3 Na ions and exports 2 K ions at the cost of hydrolyzing 1 molecule of ATP. (physicsforums.com)
  • HAP2 is a domesticated viral class II fusion protein found in diverse eukaryotes including Toxoplasma, thale cress, and fruit flies. (wikipedia.org)
  • This protein is essential for gamete fusion in these organisms. (wikipedia.org)
  • Hi all, I've run into a curious problem with a fusion protein I recently generated. (protocol-online.org)
  • My guess is that the DmrB fusion destabilizes the protein, renders it toxic, prevents its proper localization, increases turnover, etc. (protocol-online.org)
  • Protein organization on the membrane of target cells may modulate HIV-1 transmission. (jimmunol.org)
  • On the other hand, CD81 belongs to the tetraspanin family, which has been described as organizers of protein microdomains on the plasma membrane. (jimmunol.org)
  • Human immunodeficiency virus type 1 expresses on its surface envelope protein complexes (Env), 4 composed by subunits gp120 and gp41, that mediate viral attachment and membrane fusion. (jimmunol.org)
  • Methods including structural mass spectrometry, small-angle X-ray scattering, and electron microscopy have begun to provide new insight into pathways of conformational change and fusion protein function. (mdpi.com)
  • A very rapid and extended fusion was observed after cotransfection of plasmids encoding gB-008 and gDH, a hybrid protein consisting of the N-terminal 271 amino acids of gD fused to the 590 C-terminal amino acids of gH. (asm.org)
  • Inhibition by PrV gM was not limited to PrV glycoprotein-mediated fusion but also affected fusion induced by the F protein of bovine respiratory syncytial virus, indicating a general mechanism of fusion inhibition by gM. (asm.org)
  • However, no classical viral fusion protein has been identified for any member of the herpesviruses, although there are reports that constitutive expression of gB or gD in transgenic cells does increase polykaryocyte formation ( 4 , 5 ). (asm.org)
  • A4Z122_BRASO Membrane fusion protein (MFP) family protein OS=Bradyrhizobium sp. (uniprot.org)
  • Photoreceptor outer segment (OS) renewal requires a series of tightly regulated membrane fusion events which are mediated by a fusion complex containing protein and lipid components. (ovid.com)
  • Ca 2+ -dependent interactions between synaptotagmin and SNARE (soluble N -ethylmaleimide-sensitive fusion protein attachment receptor) complexes and/or anionic membranes are possible effector interactions. (jneurosci.org)
  • To ensure that membrane fusion takes place at the right place and time, influenza virus decorates the surface of its membrane with a protein called hemagglutinin. (elifesciences.org)
  • This protein senses cues provided by the target cell and then undergoes a series of transformations that lead to membrane fusion. (elifesciences.org)
  • Each of the examples of fusion just cited requires a protein catalyst. (elifesciences.org)
  • Here we identify the penta-EF-hand protein PEF1 of the genetic model fungus Neurospora crassa as part of a cellular response mechanisms against different types of membrane injury. (genetics.org)
  • Deletion of the pef1 gene in the wild-type and different lysis-prone gene knock out mutants revealed a function of the protein in maintaining cell integrity during cell-cell fusion and in the presence of pore-forming drugs, such as the plant defense compound tomatine. (genetics.org)
  • Furthermore, it is now apparent that the SNARE transmembrane segment not only anchors the protein but engages in SNARE-SNARE interactions and plays an active role in fusion. (biologists.org)
  • Thus, vesicle formation requires the uptake of targeting and fusion factors, including Rab-GTPases, tethering factors and SNAREs [soluble NSF (N-ethylmaleimide-sensitive factor) attachment protein receptors]. (biologists.org)
  • Membrane fusion of Semliki Forest virus involves homotrimers of the fusion protein. (asm.org)
  • Gallaher, W.R. (1987) Detection of a fusion peptide se-quence in the transmembrane protein of human immu-nodeficiency virus. (scirp.org)
  • An important open question is whether protein fusion machineries actively pull the fusion reaction over the present free energy barriers, or whether they rather catalyze fusion by lowering those barriers. (portlandpress.com)
  • The increased vacuole fusion was not due to aberrant protein sorting of SNAREs or recruitment of factors from the cytosol such as Ypt7p and the HOPS tethering complex. (illinois.edu)
  • Dengue virus (DV) is a compact, icosahedrally symmetric, enveloped particle, covered by 90 dimers of envelope protein (E), which mediates viral attachment and membrane fusion. (elifesciences.org)
  • The most well-characterized component, KNOLLE, a cell plate-specific soluble N-ethylmaleimide-sensitive fusion protein (NSF)-attachment protein receptor (SNARE), is a membrane fusion machine component required for plant cytokinesis. (plantphysiol.org)
  • Of these two AAA complexes, the biochemical function of Sec18p/NSF, which along with its cofactor, soluble NSF-attachment protein (α-SNAP) regulates hetero- and homotypic membrane fusion, has been the most well characterized. (plantphysiol.org)
  • Successful infection by influenza virus requires that the envelope spike protein, hemagglutinin (HA), catalyzes fusion between the viral envelope and the intracellular endosomal membrane of the target cell and creates a pore large enough to release the viral genome. (rupress.org)
  • Solid-state NMR techniques were used to characterize lipid-protein interactions in reconstituted cytochrome c oxidase and sarcoplasmic calcium pump membranes. (umich.edu)
  • The interaction of mitochondrial signal sequences with lipid model membranes and establishing TIRF microscopy as a tool to study protein binding to and lipid-protein interactions in supported membranes were at the center of his research activities. (umich.edu)
  • The antibody recognizes the ectodomain of the membrane-bound tetrameric attachment (H) protein, which together with the fusion protein and a host cell receptor executes plasma membrane fusion to deliver the viral genetic information into the cell. (prolekare.cz)
  • Both MeV and CDV entry systems rely on two surface glycoproteins for infection: the receptor-binding protein H and the fusion protein F [ 6 ]. (prolekare.cz)
  • In Vivo Efficacy of Measles Virus Fusion Protein-Derived Peptides Is Modulated by the Properties of Self-Assembly and Membrane Residence. (osu.edu)
  • Visualization of membrane protein localization and trafficking in live cells facilitates understanding the molecular basis of cellular dynamics. (ucsb.edu)
  • We describe here a method for specifically labeling the plasma membrane-localized fraction of heterologous membrane protein expression using channelrhodopsins as a case study. (ucsb.edu)
  • We determined that inhibitors of tyrosine protein kinases, dynamin GTPase and actin dynamics had little effect on binding of virions to cells but impaired membrane fusion, whereas partial cholesterol depletion and inhibitors of endosomal acidification and membrane blebbing had a severe effect at the later stage of core entry. (prolekare.cz)
  • Each of the entry protein-deficient virions had severely reduced infectivity and except for A28, L1 and L5 greatly impaired membrane fusion. (prolekare.cz)
  • The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex drives the majority of intracellular and exocytic membrane fusion events. (mpg.de)
  • The N-ethylmaleimide sensitive fusion protein (NSF) is required for fusion of lipid bilayers at many locations within eukaryotic cells. (rupress.org)
  • Using Saccharomyces cerevisiae and its vacuolar lysosome as a model, I show that coordinated interactions between the fusion protein machinery (Rab-GTPase Ypt7 and its effector Vps41), and the protein kinase Yck3, target hemifusion intermediates to control ILF formation upon vacuolar lysosome fusion. (concordia.ca)
  • Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes are the core molecular machinery of membrane fusion, a fundamental process that drives inter- and intracellular communication and trafficking. (cdc.gov)
  • Prm1p, a pheromone-regulated multispanning membrane protein, facilitates plasma membrane fusion during yeast mating. (ucsf.edu)
  • Here we show that IM30, a conserved chloroplast and cyanobacterial protein of approximately 30 kDa binds as an oligomeric ring in a well-defined geometry specifically to membranes containing anionic lipids. (au.dk)
  • Revelation of viral membrane protein structure will aid in design of improved vaccine in the future. (mepopedia.com)
  • A27 also tethers a viral fusion suppressor protein, A26, to mature virions. (mepopedia.com)
  • Furthermore, CHANG's lab also demonstrated that A27 protein complex formation through the coiled-coiled domain is crucial to its biological activity in vivo, and revealed how A27 regulates virus-induced membrane fusion through its ability to form complexes with A26 protein. (mepopedia.com)
  • The multipass membrane protein Prm1 is the only known component that acts at the step of bilayer fusion. (ucsf.edu)
  • SFV fusion is mediated by the heterotrimeric viral spike protein, which undergoes an ordered series of conformational changes following exposure to acid pH that culminate in membrane fusion. (elsevier.com)
  • The role of specific spike protein domains in fusion will be evaluated by analysis of our previously obtained virus and spike protein fusion mutants. (elsevier.com)
  • An infectious SFV clone will be used to analyze the effects of the spike protein mutations on virus assembly, infectivity, and fusion. (elsevier.com)
  • The SFV E1 spike protein subunit interacts with the target membrane to trigger fusion. (elsevier.com)
  • Influenza membrane fusion is catalyzed by hemagglutinin (HA), a class I viral fusion protein activated by low pH. (edu.au)
  • The new experimental and modeling approaches described in this review hold promise for a more complete understanding of other viral fusion systems and the protein systems responsible for cellular fusion. (edu.au)
  • Identification and characterization of LFD1, a novel protein involved in membrane merger during cell fusion in Neurospora crassa. (escholarship.org)
  • Previously, a multipass membrane protein, PRM1, was characterized and acts at the step of bilayer fusion in N. crassa. (escholarship.org)
  • Here we describe the identification and characterization of lfd-1, encoding a single pass transmembrane protein, which is also involved in membrane merger. (escholarship.org)
  • Membrane organization and cell fusion during mating in fission yeast requires multipass membrane protein Prm1. (ox.ac.uk)
  • Membrane fusion, the merger of two biological membranes without content leakage, is essential for protein transport along the exocytic and endocytic pathways in eukaryotic cells. (embopress.org)
  • The activity of the membrane fusion protein Env of Moloney mouse leukaemia virus is controlled by isomerization of the disulphide that couples its transmembrane (TM) and surface (SU) subunits. (embopress.org)
  • According to the prevailing model, the TM subunit is kept in a metastable, inactive conformation in the native fusion protein. (embopress.org)
  • In our study , we investigated the fusion between small cationic liposomes (~100 nm) and giant vesicles (tens of microns in diameter) containing increasing fractions of anionic lipids. (biophysics.org)
  • We can conclude that the fusogenic system is very efficient for membranes containing anionic lipids, which can be therapeutically interesting, because cancer cells usually expose anionic lipids in their external leaflet. (biophysics.org)
  • Membrane fusion proceeds in model membranes as well as biological membranes through the rearrangement of lipids. (springer.com)
  • Basanez G, Goni FM, Alonso A (1998) Effect of single chain lipids on phospholipase C-promoted vesicle fusion. (springer.com)
  • A large number of investigations into membrane fusion indicate various roles for individual members of the phosphoinositide class of membrane lipids. (biochemj.org)
  • Assays of membrane fusion report either the mixing or leakage of the aqueous contents of the fused entities (described here) or the mixing of membrane lipids ( Lipid-Mixing Assays of Membrane Fusion-Note 13.1 ). (thermofisher.com)
  • These results suggested that the fusion strength of SNAREs, the composition of organelle lipids and lipid-SNARE interactions could be coordinately regulated to control the rate and specificity of membrane fusion. (rice.edu)
  • A proteolytically truncated form of E1 will be used to analyze the biochemical nature of E1's interaction with the membrane and its requirement for specific lipids, and to identify and characterize the E1 domain involved in membrane binding. (elsevier.com)
  • Second, blocking HIV-1 endocytosis by a small-molecule dynamin inhibitor, dynasore, resulted in transfer of viral lipids to the plasma membrane without any detectable release of the viral content into the cytosol. (biomedcentral.com)
  • They help to ensure that vesicles fuse with the correct target compartment through a lock-and-key-like process in which α-helical structural regions of SNAREs on different membranes intertwine and zipper together to form a structure called a trans -SNARE complex 2 . (nature.com)
  • After the initial recognition step, tethers bring the vesicle into closer contact with the target membrane until interaction between SNAREs leads to trans -SNARE-complex formation and membrane fusion 2 . (nature.com)
  • Some previous reports indicated that multi-subunit tether complexes have an active role in SNARE-complex assembly, and potentially have a role in fusion, yet the precise mechanism remained elusive 2 . (nature.com)
  • The precise number of trans -SNARE complexes needed for fusion remains unclear, and might indeed vary depending on the specific fusion process. (nature.com)
  • By using our physiological yeast fusion model, the impact of these tethering factors on the SNARE topology can be investigated, along with the many other factors that come into play. (innovations-report.com)
  • Two further papers also shed light on complexin's role in regulating SNARE-mediated membrane fusion. (sciencemag.org)
  • confirm that, in neuronal systems, complexin can play a negative or positive role in SNARE-mediated membrane fusion during neurotransmitter release, potentially either clamping SNARES to prevent spontaneous fusion or promoting fusion when appropriate. (sciencemag.org)
  • C. G. Giraudo, A. Garcia-Diaz, W. S. Eng, Y. Chen, W. A. Hendrickson, T. J. Melia, J. E. Rothman, Alternative zippering as an on-off switch for SNARE-mediated fusion. (sciencemag.org)
  • A. Maximov, J. Tang, X. Yang, Z. P. Pang, T. C. Südhof, Complexin controls the force transfer from SNARE complexes to membranes in fusion. (sciencemag.org)
  • SNARE complexes are the core molecular machinery of membrane fusion, a fundamental process that drives inter- and intracellular communication and trafficking. (ens.fr)
  • We also incorporated lipid-conjugated complementary ssDNA as tethers into vesicle and target membranes, which enabled bypass of the rate-limiting docking step of fusion reactions and allowed direct observation of individual membrane-fusion events at SNARE densities as low as one pair per vesicle. (ens.fr)
  • after v- and t-SNARE docking (noted as entry into the D state), certain fractions of the populations of these immobile vesicles proceeded to fusion (noted as entry into the F state, at about 6.9 s in (i) and (ii) ) while others remained immobilized until they became invisible due to photobleaching. (ens.fr)
  • Thus, synaptotagmin is a key regulator of SNARE-mediated fusion during synaptic transmission. (jneurosci.org)
  • I compared the in vitro membrane fusion function of Sec9p and Spo20p and found that Spo20p forms a less fusion efficient SNARE complex than Sec9p. (rice.edu)
  • To analyze Sec1p function in vitro, I have utilized a well-characterized SNARE-mediated membrane fusion assay. (rice.edu)
  • The binding and fusion data strongly argue that Sec1p directly stimulates SNARE-mediated membrane fusion. (rice.edu)
  • Fusion seems to involve a cascade in which a Rab-GTPase, together with tethering factors, mediates membrane contact, which is followed by SNARE pairing and lipid bilayer mixing. (biologists.org)
  • The AFM deflection readout is used to monitor the distance between the two bilayers, which allows to observe and identify fusion processes of the two lipid membranes, while the forces needed to separate the two surfaces give insights into the formation of SNARE complexes. (springer.com)
  • Oelkers M, Witt H, Halder P, Jahn R, Janshoff A (2016) SNARE-mediated membrane fusion trajectories derived from force-clamp experiments. (springer.com)
  • This is a question that we shall discuss in this review, with particular focus on the influence of the eukaryotic SNARE-dependent fusion machinery on the final step of the reaction, the formation and expansion of the fusion pore. (portlandpress.com)
  • Maintenance of eukaryotic cellular homeostasis requires the fusion of vesicle membranes that is accomplished by a SNARE-mediated mechanism. (illinois.edu)
  • SNARE complexes are required for membrane fusion in the endomembrane system. (semanticscholar.org)
  • NSF/Sec18 disrupts these cis-SNARE complexes, allowing reassembly of their subunits into trans-SNARE complexes and subsequent fusion. (semanticscholar.org)
  • A soluble SNARE drives rapid docking, bypassing ATP and Sec17/18p for vacuole fusion. (semanticscholar.org)
  • HOPS prevents the disassembly of trans-SNARE complexes by Sec17p/Sec18p during membrane fusion. (semanticscholar.org)
  • Variable cooperativity in SNARE-mediated membrane fusion. (mpg.de)
  • Whether and how SNAREs cooperate to mediate fusion has been a subject of intense study, with estimates ranging from a single SNARE complex to 15. (mpg.de)
  • Here we show that there is no universally conserved number of SNARE complexes involved as revealed by our observation that this varies greatly depending on membrane curvature. (mpg.de)
  • Our results can be rationalized in terms of strong and weak cooperative coupling of SNARE complex assembly where each mode implicates different intermediate states of fusion that have been recently identified by electron microscopy. (mpg.de)
  • We predict that even higher variability in cooperativity is present in different physiological scenarios of fusion, and we further hypothesize that plasticity of SNAREs to engage in different coupling modes is an important feature of the biologically ubiquitous SNARE-mediated fusion reactions. (mpg.de)
  • Phosphorylated Vps41 causes the multisubunit tethering complex HOPS to dissociate from vacuolar lysosome membranes preventing efficient trans-SNARE pairing required for lipid bilayer pore formation. (concordia.ca)
  • By developing a new luminal β-lactamase complementation assay to measure MVB-vacuolar lysosome fusion in vitro, I show that both fusion events require Ypt7 and HOPS, but heterotypic fusion is distinct in that it uses a unique non-canonical Q-SNARE bundle composed of the endosomal Qa-SNARE Pep12, Qb-SNARE Vti1, and soluble Qc-SNARE Vam7, that complexes with the lysosomal R-SNARE Nyv1 to drive lipid bilayer merger. (concordia.ca)
  • We used recombinant Sec1p to test Sec1p function using a well-characterized SNARE-mediated membrane fusion assay. (rupress.org)
  • SNARE‐dependent membrane fusion requires the disassembly of cis ‐SNARE complexes (formed by SNAREs anchored to one membrane) followed by the assembly of trans ‐SNARE complexes (SNAREs anchored to two apposed membranes). (embopress.org)
  • We now report that trans ‐SNARE complexes formed during vacuole fusion are largely associated with Sec17p. (embopress.org)
  • Using a reconstituted proteoliposome fusion system, we show that trans ‐SNARE complex, like cis ‐SNARE complex, is sensitive to Sec17p/Sec18p mediated disassembly. (embopress.org)
  • HOPS thus directs the Sec17p/Sec18p chaperone system to maximize functional trans ‐SNARE complex for membrane fusion, a new role of tethering factors during membrane traffic. (embopress.org)
  • Liberated SNAREs from apposed membranes form trans ‐SNARE complexes, an essential step for fusion. (embopress.org)
  • This delivery and removal is mediated by the membrane-bound organelles of eukaryotic cells, which communicate with each other by budding off vesicles and other transport packages, which travel to, and fuse with, target membranes. (nature.com)
  • These signalling components are delivered to the cell membrane through a pathway in which vesicles containing these molecules transit through different organelles by a series of vesicle budding and fusion events. (nature.com)
  • Within our cells, we have communicating compartments called vesicles (a bubble-like membrane structure that stores and transports cellular products)," said Dr. Christopher Peters, assistant professor of biochemistry and molecular biology at BCM and lead author on the study. (innovations-report.com)
  • Giant unilamellar vesicles (GUVs) are well-established membrane models, which can be easily followed with optical microscopy and can therefore unravel key features of membrane processes. (biophysics.org)
  • Surprisingly, the resulting vesicles develop external tubes suggesting the generation of positive spontaneous curvature in the membrane. (biophysics.org)
  • Chakraborty H, Sengupta T, Lentz BR (2014) pH alters PEG-mediated fusion of phosphatidylethanolamine-containing vesicles. (springer.com)
  • In order to clarify the dynamics of the fusion process in more detail, scientists from the Max Planck Institute of Colloids and Interfaces developed two different protocols for the fusion of unilamellar vesicles, which had a diameter of tens of micrometers but consist of only a single lipid membrane with a thickness of about four nanometers. (nanowerk.com)
  • The two protocols provide two different methods of bringing a pair of unilamellar vesicles into close contact, to initiate the fusion of their membranes in a controlled manner and to study the subsequent fusion dynamics with high temporal resolution. (nanowerk.com)
  • Once close contact was established, membrane fusion was induced by exposing the vesicles to an additional electric pulse. (nanowerk.com)
  • Indeed, only a few hundred microseconds after the initiation of the fusion process, the fusion neck connecting the two vesicles has already reached a diameter of a couple of micrometres as shown in Figure 1(b). (nanowerk.com)
  • In this study, we showed the use of self-assembled DNA-nanostructure rings to template uniform-sized small unilamellar vesicles containing predetermined maximal number of externally facing SNAREs to study the membrane-fusion process. (ens.fr)
  • This process requires mechanisms both for sensing Ca 2+ and subsequently fusing transmitter-filled synaptic vesicles with the presynaptic membrane. (jneurosci.org)
  • At the nerve terminal, however, additional levels of regulation are required to prevent the fusion of synaptic vesicles with the presynaptic membrane before Ca 2+ entry and then expedite the synchronous fusion of multiple vesicles when Ca 2+ levels rise. (jneurosci.org)
  • Leakage of aqueous contents from cells or vesicles as a result of lysis, fusion or physiological permeability can be detected fluorometrically using low molecular weight soluble tracers. (thermofisher.com)
  • Sec9p interacts with Sso1/2p and Snc1/2p to mediate membrane fusion between post-Golgi vesicles and the plasma membrane during vegetative growth. (rice.edu)
  • Carrier vesicles fuse with target organelles, secretory vesicles fuse with the plasma membrane, mitochondria fuse with each other. (elifesciences.org)
  • Here, we use mesoscopic simulations3 to study the fusion of 28-nm-diameter vesicles to 50 × 50 nm2 planar membrane patches over 2 μs. (epfl.ch)
  • This nomenclature turned out to be somewhat ambiguous, since t-SNAREs are also found on vesicles and v-SNAREs can be found on target membranes. (biologists.org)
  • Recorded time courses of lipid-mixing, content-mixing, and content-leakage associated with fusion of 23 nm vesicles in the presence of poly(ethylene glycol) at multiple temperatures were fitted globally to a three-step sequential model to yield rate constants and thereby activation thermodynamics for each step of the process, as well as probabilities of occurrence of lipid-mixing, content-mixing, or content-leakage in each state. (sigmaaldrich.com)
  • Physiological membrane vesicles are built to separate reaction spaces in a stable manner, even when they accidentally collide or are kept in apposition by spatial constraints in the cell. (portlandpress.com)
  • At the end of mitosis membrane vesicles are targeted to the surface of chromatin and fuse to form a continuous nuclear envelope. (rupress.org)
  • When isolated membranes are added to this decondensed chromatin a specific subfraction of membrane vesicles (approximately 70 nM in diameter) bind to the chromatin, but these vesicles do not fuse to each other. (rupress.org)
  • With respect to vesicle fusion, we have found that vesicles prebound to chromatin will fuse to each other when ATP and GTP are present in the boiled extract. (rupress.org)
  • Intracellular membrane vesicles containing the GLUT4 glucose transporter move towards the cell cortex in response to insulin and then fuse with the plasma membrane. (semanticscholar.org)
  • Current research interests include studies on virus entry into cells by membrane fusion, neurotransmitter release at synapses by exocytosis of synaptic vesicles at nerve termini, and the study of the structures of bacterial outer membrane transporters by NMR. (umich.edu)
  • 15_18_Clathrin_EM.jpg Clathrin molecules form basketlike cages that help shape membranes into vesicles. (coursehero.com)
  • transport vesicles to their target membranes. (coursehero.com)
  • This is accomplished in part by the faithful delivery of Golgi-derived secretory vesicles by fusion with the plasma membrane. (rupress.org)
  • And how do the tethers bring the membranes of the two fusing compartments closer together before the SNAREs interact with each other? (nature.com)
  • The authors provide evidence that SNAREs alone can achieve a state of only partial fusion between the two fusing membranes, known as hemi-fusion, in which only one of the lipid layers of each of the fusing membranes has fused ( Fig. 1 ), and that HOPS is required to fully complete the fusion process. (nature.com)
  • show that a structural motif within complexin appears to act as a molecular switch directly interacting with SNAREs during membrane fusion. (sciencemag.org)
  • Despite the identification of SNAREs as the minimal membrane fusion machinery for yeast intracellular fusion, additional regulatory mechanisms remain to be elucidated. (rice.edu)
  • Whereas Rab-GTPases seem to mediate the initial membrane contact, SNAREs appear to lie at the center of the fusion process. (biologists.org)
  • Nevertheless, recent observations are shedding light on the role of SNAREs in membrane fusion. (biologists.org)
  • SNAREs were initially classified according to their preferential localization as vesicle-localized (v)- or target-membrane-bound (t)-SNAREs ( Rothman, 1994 ). (biologists.org)
  • Abdulreda MH, Bhalla A, Rico F, Berggren P-O, Chapman ER, Moy VT (2009) Pulling force generated by interacting SNAREs facilitates membrane hemifusion. (springer.com)
  • Fusion priming does not involve contact between vacuoles but includes the disassembly of complexes of SNAREs on the same membrane (cis) by Sec18p (NSF) and its cochaperone Sec17p (a-SNAP). (illinois.edu)
  • however, when Sec1p is allowed to bind to SNAREs before reconstitution, significantly more Sec1p binding is detected and fusion is stimulated in a concentration-dependent manner. (rupress.org)
  • Although it is clear that SNAREs provide the mechanical force required for membrane fusion, it is also clear that they do not work alone in the cell. (rupress.org)
  • ABSTRACT: Our recent coarse-grained (CG) molecular dynamics (MD) simulations of membranes with a hemifused-ribbon (λ-shaped) geometry showed curvature-driven demixing leading to enrich ment in dioleoyl-phosphatidylethanolamine (DOPE) in a negatively-curved region (at C = -0.8 nm-1) of a DOPE/dipalmitoyl-phosphati-dylcholine (DPPC) membrane. (scirp.org)
  • abstract = "With the availability of a new technique, the freeze fracture, freeze etch technique, it became possible to localize internal membrane components at specific sites. (elsevier.com)
  • The peptide regions required to drive fusion are formed from the turns between the β-sheets. (wikipedia.org)
  • Then, gp41 inserts its hydrophobic motif (fusion peptide) in the cell membrane, triggering virus-cell membrane fusion. (jimmunol.org)
  • They are composed of one or two type I integral membrane glycoproteins, contain extended ectodomains carrying N-linked carbohydrates, form higher-order oligomers, are present on the viral membrane at high surface density, and contain a fusion peptide in a membrane-anchored subunit. (asm.org)
  • In general, it is suggested that a triggered conformational change exposes a previously cryptic fusion peptide, which is then able to insert into the lipid bilayer and thus initiate the fusion reaction by disturbing the membrane integrity. (asm.org)
  • Peptide competition studies suggest that optimization of fusion may be due to the formation of a fusion competent peripherin/ rds C-terminus in the presence of ROM-1. (ovid.com)
  • It has been suggested that the coiled-coil domains present the fusogenic peptide in a conformation or geometry favorable for membrane fusion. (nih.gov)
  • To test the hypothesis that trimerization of fusogenic peptide is related to optimal fusion, we have designed and synthesized a triple-stranded coiled-coil X31 peptide, also known as the ccX31, which mimics the influenza virus hemagglutinin fusion peptide in the fusion-active state. (nih.gov)
  • We compared the membrane interactive properties of ccX31 versus the monomeric X31 fusogenic peptide. (nih.gov)
  • Our results are consistent with the hypothesis that oligomerization of fusogenic peptide promotes membrane fusion, possibly by enhancing localized destabilization of lipid bilayers. (nih.gov)
  • Pähler G, Lorenz B, Janshoff A (2013) Impact of peptide clustering on unbinding forces in the context of fusion mimetics. (springer.com)
  • A 20 amino acid peptide from the N-terminus of the influenza HA fusion peptide (WT20) assumed the oblique orientation at the interface between water and the membrane made up of dipalmitoylphosphatidylcholine (DPPC)/palmitic acid (PA), as reported previously for different membranes. (scirp.org)
  • Taken together, these results imply that the influenza HA fusion peptide can have substantial effects on the membrane curvature and can assume a wide range of orientation/position in membranes depending on the local environment of the lipid/water system. (scirp.org)
  • Effects of mutations in HA indicate that withdrawal of the fusion peptide from a pocket in the pre-fusion trimer is rate-limiting for both events, but the requirement for cooperative action of several HAs to bring the fusing membranes together leads to a long-lived intermediate state for single, extended HA trimers. (edu.au)
  • Fusion activation following receptor binding is proposed to involve the exposure of a second proteolytic site (S2'), cleavage of which is required for the fusion peptide release11,12. (crick.ac.uk)
  • This involves exposure of a hydrophobic peptide, the fusion peptide, and the insertion of the latter into the target membrane. (embopress.org)
  • Subsequently, the TM subunit back‐folds so that the fusion peptide and the membrane anchor orient into the same direction. (embopress.org)
  • To understand these mechanisms, researchers have strived to devise in vitro systems that mimic fusion events in vivo . (nature.com)
  • However, many questions remain about the mechanisms driving the regulation and execution of the membrane fusion (in which the lipid bilayers on two separate membranes fuse to form one bilayer) underlying this process. (nature.com)
  • These subsequent self-contacts are eliminated, and the potential elimination mechanisms were speculated as membrane fusion ( 5 ) or macropinocytosis ( 6 ). (pnas.org)
  • Fusion pores develop during and intracellular fusion events suggesting similar mechanisms for many, if not all, fusion events. (sciencemag.org)
  • Although the membrane of fungi is the target or important clinical drugs and agricultural fungicides, the molecular mechanisms, which mediate membrane repair in these organisms remain elusive. (genetics.org)
  • We propose that in fungi plasma membrane repair constitutes an additional line of defense against membrane disturbing drugs, thereby expanding the current model of fungal drug resistance mechanisms. (genetics.org)
  • To investigate the molecular mechanisms underlying these steps in nuclear envelope assembly, we have developed a defined cell-free system in which the binding and fusion steps in nuclear envelope assembly can be examined separately. (rupress.org)
  • Cell-to-cell membrane fusion assays have been employed widely to study HIV-1 entry mechanisms because they are easy to operate and do not need an infectious virus. (asm.org)
  • Although critical for homeostasis and remodeling, it is not clear how ILFs are formed during the homotypic lipid bilayer fusion reaction, nor is it clear whether similar molecular mechanisms orchestrate MVB-lysosome fusion. (concordia.ca)
  • The molecular mechanisms driving plasma membrane fusion in these processes remain unknown. (ucsf.edu)
  • The mechanisms by which these mutations affect fusion will be determined by analysis of the series of known molecular events that lead to fusion, including acid-dependent conformational changes and interactions with the target membrane. (elsevier.com)
  • Despite its essential role in development, molecular mechanisms of membrane merger during cell-cell fusion in most eukaryotic organisms remain elusive. (escholarship.org)
  • Simulations of WT20 embedded in bilayer membranes made up of dioleoylphos-phatidylethanolamine (DOPE) and DPPC/PA showed a positive curvature-inducing effect, whereas WT20 showed a negative curvature-inducing effect on a DPPC bilayer. (scirp.org)
  • We hypothesize that curvature-driven lipid sorting and energetically favored localization of domain boundaries at sharp bends in the membranes may collaborate to assist intracellular lipid sorting. (scirp.org)
  • Although cholesterol has a negative spontaneous monolayer curvature, it is hard to estimate this effect on membrane curvature because the amount of curvature stress introduced by cholesterol is a function of the other phospholipids surrounding it ( Huang and Feigenson, 1999 ). (rupress.org)
  • In spite of extensive research on exploring the mechanism of membrane fusion, a clear molecular understanding of intermediate and pore formation is lacking. (springer.com)
  • Likewise, membrane fusion is the basic molecular process that controls the communication between cells via the secretion of hormones, neurotransmitters, and growth factors. (nanowerk.com)
  • Molecular evidence is provided that different distances of E 4 in CP n E 4 and K 4 in CP n K 4 from the bilayer represent an important mechanism, which enables fusion. (rsc.org)
  • We have previously used single-virion measurements of fusion kinetics to study the molecular mechanism of influenza-virus envelope fusion. (harvard.edu)
  • Although the crystal structures for both neutral and pH-activated forms of HA are known, the molecular mechanism underlying the merger of two membranes in HA-mediated fusion is still unclear ( 6 ). (asm.org)
  • Advances in molecular electrophysiology have led to the identification of more ion-channel genes than there are identified membrane currents. (springer.com)
  • Molecular characterization of the identified mAb epitope (which locates in the membrane-distal stalk module called "spacer"), enabled us to unravel two sequential conformational changes occurring in CDV H-tetramers that stand at the core of the molecular mechanism translating receptor binding to F-triggering. (prolekare.cz)
  • Using new insights from these results, I present refined working models describing the molecular underpinnings of homotypic vacuolar lysosome and MVB-vacuolar lysosome fusion. (concordia.ca)
  • As for most cell-cell fusion events, the molecular details of membrane fusion during yeast mating are poorly understood. (ucsf.edu)
  • A crucial issue in studies of all of these viruses is the molecular mechanism of membrane fusion, a critical function for both viruses and cells. (elsevier.com)
  • Our goal is to define the molecular features of a membrane fusion reaction, using the well defined SFV system and a combination of biochemical, genetic, and immunological approaches. (elsevier.com)
  • In this study, we performed a functional analysis of the membrane fusion properties of West Nile virus (WNV) with liposomal target membranes. (microbiologyresearch.org)
  • The process of membrane fusion is fundamental to cellular organization and has been the focus of a vast literature. (sciencemag.org)
  • Membrane fusion is a ubiquitous process, essential for cellular development, communication, and drug delivery. (biophysics.org)
  • Membrane fusion is essential in several cellular processes in the existence of eukaryotic cells such as cellular trafficking, compartmentalization, intercellular communication, sexual reproduction, cell division, and endo- and exocytosis. (springer.com)
  • Disruption of tetraspanin-based membrane microdomains interferes with important cellular processes, such as signal transduction, Ag presentation, cell migration, and cellular adhesion ( 14 , 17 , 18 , 19 ). (jimmunol.org)
  • Membrane fusion underlies many cellular events, including secretion, exocytosis, endocytosis, organelle reconstitution, transport from endoplasmic reticulum to Golgi and nuclear envelope formation. (biochemj.org)
  • These refolding events ultimately drive the fusion of viral and cellular membranes leading to delivery of the genetic cargo. (mdpi.com)
  • During this process, hemagglutinin molecules insert into the target cell membrane to bring together the viral and cellular membranes. (elifesciences.org)
  • Enveloped viruses fuse with a cellular membrane to deposit their genomic contents into the cytosol. (elifesciences.org)
  • Plasma membrane damage is a common occurence during cellular growth and development. (genetics.org)
  • New 3-D maps of water distribution during cellular membrane fusion are accelerating scientific understanding of cell development, which could lead to new treatments for diseases associated with cell fusion. (phys.org)
  • We used neutrons to probe our samples, because water typically can't be seen by x-rays, and because other imaging techniques can't accurately capture the extremely rapid and dynamic process of cellular fusion," said Durgesh K. Rai, co-author and now a post-doctoral associate at the Cornell High Energy Synchrotron Source at Cornell University. (phys.org)
  • Accordingly, cellular events that breach the membrane are tightly regulated1. (epfl.ch)
  • Ion channels in the plasma membrane play a critical role in cellular function. (springer.com)
  • The components of the cellular machinery that accomplish the various complex and dynamic membrane fusion events that occur at the division plane during plant cytokinesis, including assembly of the cell plate, are not fully understood. (plantphysiol.org)
  • Entry of enveloped viruses into cells can be divided into three steps: (i) close apposition of viral and cellular membranes, (ii) lipid mixing of the outer membrane leaflets leading to formation of a hemifusion intermediate, and (iii) formation and expansion of a fusion pore allowing entry of the viral nucleoprotein or core into the cytoplasm [1] . (prolekare.cz)
  • Lysosomes also undergo homotypic membrane fusion for remodeling in response to cellular stress, or aging, or for organelle inheritance. (concordia.ca)
  • A major step in infection is fusion of the viral and host cellular membranes, a process with large kinetic barriers. (edu.au)
  • Satir, B 1974, ' Ultrastructural aspects of membrane fusion ', Journal of Supramolecular and Cellular Biochemistry , vol. 2, no. 5-6, pp. 529-537. (elsevier.com)
  • It consists of consecutive steps including docking of the two bilayers, membrane destabilization, fusion of the outer leaflets (hemifusion), opening and expansion of the fusion neck and finally full fusion. (biophysics.org)
  • The cationic liposomes induce mainly docking and hemifusion with neutral GUVs, resulting in an increase in membrane tension that eventually leads to vesicle rupture and restructuration in tubular morphologies (images in the background). (biophysics.org)
  • This volume of Current Topics in Membranes focuses on Membrane Fusion, beginning with fusion and fission of lipid bilayers, with reviews focused on hemifusion and dynamic remodeling of membranes catalyzed by dynamin. (researchandmarkets.com)
  • We were able to observe all fusion intermediates including transient fusion, formation of a stalk, hemifusion and the completion of a fusion pore. (utexas.edu)
  • In the intermediate fusion phase, known as hemifusion, the water is significantly reduced and squeezed into pockets around a stalk-a highly curved lipid "bridge" connecting two membranes before fusion fully occurs. (phys.org)
  • Shuo Qian et al, Grazing-Angle Neutron Diffraction Study of the Water Distribution in Membrane Hemifusion: From the Lamellar to Rhombohedral Phase, The Journal of Physical Chemistry Letters (2018). (phys.org)
  • Recent work indicates that the fusion process itself may comprise two stages and proceed via a hemifusion intermediate. (biologists.org)
  • Accumulation of organelle content is signaled to the surface of yeast vacuoles in order to increase their storage capacity by homotypic membrane fusion. (biologists.org)
  • These distinct stages of cell plate biogenesis likely involve both heterotypic and homotypic membrane fusion events. (plantphysiol.org)
  • This dissertation describes advances made in a fluorescence microscopy-based single-particle fusion assay to overcome the limitations of ensemble measurements in these types of studies. (harvard.edu)
  • We introduce a novel assay for membrane fusion of solid supported membranes on silica beads and on coverslips. (utexas.edu)
  • The detailed information provided by this assay makes it ideally suited for studies of early events in pure lipid bilayer fusion or fusion assisted by fusogenic molecules. (utexas.edu)
  • A transient transfection-fusion assay was established to investigate membrane fusion mediated by pseudorabies virus (PrV) glycoproteins. (asm.org)
  • In these studies we investigated the role of peripherin's non-glycosylated homolog, ROM-1, in OS fusion using a COS cell heterologous expression system and a well characterized cell free fusion assay system. (ovid.com)
  • the ANTS/DPX fluorescence quenching assay has since been widely used to detect membrane fusion. (thermofisher.com)
  • Pictorial representation of the ANTS/DPX vesicle-fusion assay. (thermofisher.com)
  • Pictorial representation of the terbium/dipicolinic acid (DPA) fluorescence enhancement assay for vesicle fusion. (thermofisher.com)
  • Note that this assay will detect any process that causes leakage of aqueous contents, including fusion, lysis or permeabilization. (thermofisher.com)
  • In a modification of this assay designed to specifically detect vesicle fusion, a nonfluorescent Co 2+ complex of calcein contained in a vesicle is disrupted upon fusion with a second vesicle that delivers EDTA, a chelator of Co 2+ . (thermofisher.com)
  • I tested the ability of Sec1p to regulate fusion in the fusion assay. (rice.edu)
  • From studies that use an in vitro assay for fusion of SFV with liposomes, we show that the E1 trimer is efficiently expressed during virus-mediated membrane fusion. (asm.org)
  • Membrane fusion was monitored continuously using a lipid mixing assay involving the fluorophore, pyrene. (microbiologyresearch.org)
  • We established a human immunodeficiency virus type 1 (HIV-1) envelope (Env)-mediated membrane fusion assay and examined the small-molecule CCR5 antagonist TAK-779 and its derivatives for their inhibitory effects on HIV-1 Env-mediated membrane fusion and viral replication. (asm.org)
  • The membrane fusion assay is based on HIV-1 long terminal repeat-directed β- d -galactosidase reporter gene expression in CD4- and CCR5-expressed HeLa (MAGI-CCR5) cells after cocultivation with effector 293T cells expressing HIV-1 Env. (asm.org)
  • These results indicate that the HIV-1 Env-mediated membrane fusion assay is a useful tool for the evaluation of entry inhibitors. (asm.org)
  • We have used the binding pair to develop a channelrhodopsin membrane localization assay that is amenable to high-throughput screening for opsin discovery and engineering. (ucsb.edu)
  • In this review, we have discussed about various putative functions of fusion peptides by which they reduce activation barrier and thus promote membrane fusion. (springer.com)
  • A careful analysis of the discussed effects of fusion peptides on membranes might open up new possibilities for better understanding of the membrane fusion mechanism. (springer.com)
  • Chakraborty H, Tarafdar PK, Klapper DG, Lentz BR (2013) Wild-type and mutant hemagglutinin fusion peptides alter bilayer structure as well as kinetics and activation thermodynamics of stalk and pore formation differently: mechanistic implications. (springer.com)
  • These data provide crucial insights as to how fusion is initiated and highlight the importance of both peptides in this process. (rsc.org)
  • The binding domain is rich in α-helices and hydrophobic fusion peptides located near the N-terminus. (wikipedia.org)
  • In previous work, we have generated potent MV fusion inhibitors by dimerizing the F-derived peptides and conjugating them to cholesterol. (osu.edu)
  • We have shown that prophylactic intranasal administration of our lead fusion inhibitor efficiently protects from MV infection in vivo We show here that peptides tagged with lipophilic moieties self-assemble into nanoparticles until they reach the target cells, where they are integrated into cell membranes. (osu.edu)
  • The self-assembly feature enhances biodistribution and the half-life of the peptides, while integration into the target cell membrane increases fusion inhibitor potency. (osu.edu)
  • The results suggest a new framework for developing effective fusion inhibitory peptides. (osu.edu)
  • We have shown that fusion-inhibitory peptides delivered intranasally provide effective prophylaxis against MV infection. (osu.edu)
  • This might subsequently guide the fusion peptides in extended TM subunits into the target membrane. (embopress.org)
  • While contacting membranes from neighboring epithelial cells rapidly assemble and maintain junctional complexes, it is unclear why self-contacting membranes from a single cell, despite similar surface binding conditions, do not. (pnas.org)
  • Whereas opposing membranes from neighboring cells rapidly assemble junctional complexes, self-contacting membranes curiously do not, suggesting that cells have the ability to prevent the maturation of self-junctions. (pnas.org)
  • These flexible membrane extensions are capable of touching different regions of their own membrane surface, yet, mature cell junctional complexes have not been observed at self-contacts. (pnas.org)
  • Multiprotein complexes that have been conserved in eukaryotes carry out the basic reactions of fusion. (illinois.edu)
  • The thylakoid membrane of chloroplasts and cyanobacteria is a unique internal membrane system harbouring the complexes of the photosynthetic electron transfer chain. (au.dk)
  • These findings reveal that membrane fusion is integral to the most common prokaryotic cell fate, phage lysis, and constitutes an unprecedented topological mechanism for the removal of the last barrier to viral release. (pnas.org)
  • Thus, the mechanism of membrane fusion can be addressed in a very simple system accessible to the power of phage genetics. (pnas.org)
  • This is the first demonstration of self-contact-induced membrane fusion in mammalian cells and that membrane fusion may be an underlying mechanism for seamless tubule formation. (pnas.org)
  • This self-contact-induced membrane fusion is a key elimination mechanism for unwanted self-junctions and may be a feature of cell self-recognition. (pnas.org)
  • The many factors that contribute to how cells communicate and function at the most basic level are still not fully understood, but researchers at Baylor College of Medicine have uncovered a mechanism that helps explain how intracellular membranes fuse, and in the process, created a new physiological membrane fusion model. (innovations-report.com)
  • Traditional techniques to study infection neutralization by antibodies or the membrane fusion process rely on ensemble measurements, confounding the precise mechanism of infection neutralization and obscuring transient conformational intermediates. (harvard.edu)
  • Specifically, Ca 2+ binding by the C 2 B domain of synaptotagmin is required at intact synapses, yet the mechanism whereby Ca 2+ binding results in vesicle fusion remains controversial. (jneurosci.org)
  • However, the mechanism that couples Ca 2+ binding by synaptotagmin with vesicle fusion remains controversial. (jneurosci.org)
  • Although this model is based almost entirely on in vitro studies of the original clones of NSF and alpha-SNAP, it is nevertheless widely assumed that this mechanism of membrane fusion is conserved in all eukaryotic cells. (nih.gov)
  • Membrane fusion is the mechanism for directed interchange of contents among intracellular compartments. (elifesciences.org)
  • Unraveling a three-step spatiotemporal mechanism of triggering of receptor-induced Nipah virus fusion and cell entry. (umassmed.edu)
  • Gething, M.J., Doms, R.W., York, D. and White, J. (1986) Studies on the mechanism of membrane fusion: Site- specific mutagenesis of the hemagglutinin of influenza virus. (scirp.org)
  • Several class C ABC transporters interact with factors that are important in the fusion mechanism while others have been implicated in lipid translocation activity. (illinois.edu)
  • We show that ~12-14 bound molecules per particle (~20-25% occupancy) completely prevent fusion, consistent with the proposed mechanism. (elifesciences.org)
  • This intermediate is thus a fundamental aspect of the fusion mechanism. (edu.au)
  • With a better understanding of homotypic vacuolar lysosome fusion and ILF formation, I next determined if MVB-vacuolar lysosome fusion relies on a similar mechanism. (concordia.ca)
  • The findings shed light on the viral fusion regulation mechanism of vaccinia virus, a member of poxvirus family that also contains variola virus, the etiological disease of smallpox disease. (mepopedia.com)
  • Revertants of a mutation that blocks virus fusion will be selected and characterized for their genotype and fusion mechanism. (elsevier.com)
  • The cell fusion frequency of both Δlfd-1 and ΔPrm1 mutants was sensitive to extracellular calcium concentration and was associated with an increase in cell lysis, which was suppressed by a calcium-dependent mechanism involving a homologue to synaptotagmin. (escholarship.org)
  • The mechanism of restriction of HIV-1 fusion at the cell surface and/or the factors that aid the virus entry from endosomes remain unclear. (biomedcentral.com)
  • The influenza surface glycoprotein hemagglutinin (HA) is a potential target for antiviral drugs because of its key roles in the initial stages of infection: receptor binding and the fusion of virus and cell membranes. (rcsb.org)
  • The fusion glycoproteins that decorate the surface of enveloped viruses undergo dramatic conformational changes in the course of engaging with target cells through receptor interactions and during cell entry. (mdpi.com)
  • Lorenz B, Keller R, Sunnick E, Geil B, Janshoff A (2010) Colloidal probe microscopy of membrane-membrane interactions: from ligand-receptor recognition to fusion events. (springer.com)
  • Skehel, J.J. and Wiley, D.C. (2000) Receptor binding and membrane fusion in virus entry: The influenza hemag-glutinin. (scirp.org)
  • Both receptor binding and membrane fusion activities are mediated by the virus Spike glycoprotein, S5-7. (crick.ac.uk)
  • upon receptor engagement by H, the prefusion F undergoes a structural transition, extending and inserting into the target cell membrane and then refolding into a postfusion structure that fuses the viral and cell membranes. (osu.edu)
  • The peripheral subunit carries the receptor‐binding capacity and the TM subunit the fusion activity. (embopress.org)
  • The organization and regulation of membrane-fusion reactions, then, are crucial for virtually every membrane-bound biological process. (nature.com)
  • Membrane fusion is critical for many biological processes, especially in eukaryotic development and viral entry. (wikipedia.org)
  • These diverse roles underscore the importance of these phospholipids in the fusion of biological membranes. (biochemj.org)
  • In this latest volume in the renowned Subcellular Biochemistry series, some aspects of fusion of biological membranes as well as related problems are presented. (booktopia.com.au)
  • In the first protocol, artificial fusogenic molecules (a liposome whose outer wall contains molecules that cause cell fusion) or ligands, synthesized by the collaborators from Coll ge de France, were incorporated into the lipid membranes. (nanowerk.com)
  • Based on this strategy, we previously developed nanocarriers consisting of a nucleic acid core particle coated with four lipid membranes [Akita, et al. (sigmaaldrich.com)
  • Until now, coating a core particle with an odd number of lipid membranes was challenging. (sigmaaldrich.com)
  • To produce nanocarriers with an odd number of lipid membranes, we developed a novel coating method involving lipid nano-discs, also known as bicelles, as a material for packaging DNA in a carrier with an odd number of lipid membranes. (sigmaaldrich.com)
  • In this procedure, bicelles fuse to form an outer coating that resembles a patchwork quilt, which allows the preparation of nanoparticles coated with only three lipid membranes. (sigmaaldrich.com)
  • Moreover, the transfection activity of dendritic cells with these three-membrane nanoparticles was higher than that for nanoparticles coated with four lipid membranes. (sigmaaldrich.com)
  • In summary, we developed novel nanoparticles coated with an odd number of lipid membranes using the novel "patchwork-packaging method" to deliver plasmid DNA into the nucleus via membrane fusion. (sigmaaldrich.com)
  • Fusion requires the mildly acidic pH of the endosomal milieu in a cell-dependent manner ( Nicola, 2016 ). (frontiersin.org)
  • Tri-membrane nanoparticles produced by combining liposome fusion and a novel patchwork of bicelles to overcome endosomal and nuclear membrane barriers to cargo delivery. (sigmaaldrich.com)
  • However, including the endosomal membrane and two nuclear membranes, cells possess three intracellular membranous barriers. (sigmaaldrich.com)
  • Influenza virus penetrates cells by fusion of viral and endosomal membranes catalyzed by the viral hemagglutinin (HA). (edu.au)
  • Loss-of-function mutations that impair MVB maturation-deleting the endosomal Na+(K+)/H+ exchanger NHX1 or components of the ESCRT machinery that drive ILV formation blocks heterotypic membrane fusion. (concordia.ca)
  • Taken together, the data suggest that HSV-1 envelope cholesterol is important for viral entry and infectivity due to a critical role in membrane fusion. (frontiersin.org)
  • These data indicate that CD9 and CD81 have an important role in membrane fusion induced by HIV-1 envelope. (jimmunol.org)
  • D'Agostino and colleagues investigated fusion between vacuoles in the yeast Saccharomyces cerevisiae to test whether a multi-subunit tether complex called the HOPS complex has a role beyond aiding the docking process. (nature.com)
  • We conclude that the mechanistic properties of NSF and SNAPs are shared by Sec18p and Sec17p, thus demonstrating that the biochemistry of membrane fusion is conserved from yeast to mammals. (nih.gov)
  • I also tried to identify the fusogens mediating yeast intercellular fusion using proteomic methods. (rice.edu)
  • The core fusion machinery has been elucidated in liposomes but many regulatory factors are being discovered in the context of the yeast vacuole. (illinois.edu)
  • Sec18p (NSF)-driven release of Sec17p (alpha-SNAP) can precede docking and fusion of yeast vacuoles. (semanticscholar.org)
  • Other topics discussed include viral fusion, intracellular fusion, developmental cell fusion, and theoretical modeling. (researchandmarkets.com)
  • In combination, the approaches provide a significantly richer portrait of viral fusion glycoprotein structural variation and fusion activation as well as inhibition by neutralizing agents. (mdpi.com)
  • These include intracellular transportation, cell-to-cell fusion and viral fusion. (rice.edu)
  • Membrane fusion was subsequently induced by the local addition of ions that form a complex between two fusogenic molecules embedded in the opposing membranes. (nanowerk.com)
  • Using a self-contact-inducing micropillar array, we demonstrate that self-contacts of normal epithelial cells are rapidly eliminated by fusion between the two opposing plasma membrane regions of a single cell. (pnas.org)
  • This type of self-avoidance is based on surface chemistry defined by the receptors on plasma membrane. (pnas.org)
  • The cationic liposomes have been developed as a promising drug carrier system, as they are able to fuse with the plasma membrane and efficiently transport encapsulated material to the cytosol. (biophysics.org)
  • Degranulation involves the regulated fusion of granule membrane with plasma membrane. (umich.edu)
  • Complex" LUVs of PC∶PE∶SM∶PI∶PS (24∶27∶20∶16∶13, designed to emulate neutrophil plasma membranes) also showed very low rates of both lipid mixing and contents mixing. (umich.edu)
  • Membrane remodeling, which occurs in neutrophil plasma membranes upon stimulation, was simulated by incorporating low levels of phosphatidic acid (PA) or a diacylglycerol (DAG) into complex LUVs containing 50% cholesterol. (umich.edu)
  • These results suggest that the rate of degranulation may be increased by a rise in the cholesterol level of either the inner face of the plasma membrane or the outer face of the granule membrane. (umich.edu)
  • Our results provide direct support for the hypothesis that plasma membrane penetration, specifically by the C 2 B domain of synaptotagmin, is the critical effector interaction for coupling Ca 2+ binding with vesicle fusion. (jneurosci.org)
  • Maintaining the integrity of their protective plasma membrane is a primary requirement of cells. (epfl.ch)
  • Indirect immunofluorescence shows that endogenous Sec1p is found primarily at the bud neck in newly budded cells and in patches broadly distributed within the plasma membrane in unbudded cells. (rupress.org)
  • The growth and division of cells requires a regulated deposition of new plasma membrane. (rupress.org)
  • i.e., well before the two plasma membranes have come in contact. (ucsf.edu)
  • Electron microscopic analysis reveals that the two plasma membranes in these mating pairs are tightly apposed, remaining separated only by a uniform gap of approximately 8 nm. (ucsf.edu)
  • This phenotype suggests a role for Prm1p in plasma membrane fusion. (ucsf.edu)
  • In its absence, mutant mating pairs lyse or arrest in the mating reaction with tightly apposed plasma membranes. (ucsf.edu)
  • S. pombe prm1Δ mutant exhibits an almost complete blockade in cell fusion and an abnormal distribution of the plasma membrane and cell wall in the area of cell-cell interaction. (ox.ac.uk)
  • Time-lapse analyses show that in the wild-type S. pombe strain, the distribution of phosphatidylserine in the cytoplasmic leaflet of the plasma membrane undergoes some modification before an opening is observed in the cross wall at the cell-cell contact region. (ox.ac.uk)
  • plasma membrane forms invaginations and fingers that sometimes collapse/retract and that are sometimes strengthened by the synthesis of cell-wall material. (ox.ac.uk)
  • We recently provided evidence that HIV-1 enters HeLa-derived TZM-bl and lymphoid CEMss cells by fusing with endosomes, whereas its fusion with the plasma membrane does not proceed beyond the lipid mixing step. (biomedcentral.com)
  • Furthermore, we attempted to deliberately redirect virus fusion to the plasma membrane, using two experimental strategies. (biomedcentral.com)
  • The block of HIV-1 fusion with the plasma membrane at a post-lipid mixing stage shows that this membrane is not conducive to fusion pore formation and/or enlargement. (biomedcentral.com)
  • The above evidence, while supporting HIV-1 fusion with the plasma membrane, are somewhat indirect and generally do not rule out the existence of an endocytic entry pathway for this virus. (biomedcentral.com)
  • While adult somatic cells do not typically undergo membrane fusion under normal conditions, gametes and embryonic cells follow developmental pathways to non-spontaneously drive membrane fusion, such as in placental formation, syncytiotrophoblast formation, and neurodevelopment. (wikipedia.org)
  • 1993) have been shown to be required for vesicular membrane fusion within cells and sufficient to drive membrane fusion in vitro (Nickel et al. (rice.edu)
  • Incorporation of PA in the lipid bilayer stimulates Sec9p or Spo20p mediated membrane fusion, likely by decreasing the energetic barrier during membrane merger. (rice.edu)
  • Membrane fusion is the merger of two lipid bilayers into one continuous membrane. (illinois.edu)
  • The Δlfd-1 mutant shows a similar, but less severe, membrane merger defect as a ΔPrm1 mutant. (escholarship.org)
  • They are emerging as the key hub element controlling the membrane architecture of eukaryotic cells. (elsevier.com)
  • Membrane fusion is a rational strategy for crossing intracellular membranes that present barriers to liposomal nanocarrier-mediated delivery of plasmid DNA into the nucleus of non-dividing cells, such as dendritic cells. (sigmaaldrich.com)
  • Published data on fusion inhibition by antibodies to the 'stem' of influenza virus hemagglutinin (HA) now allow us to incorporate into simulations the provision that some HAs are inactive. (harvard.edu)
  • Here recent studies that highlight the utility of these complementary approaches will be reviewed with a focus on the well-characterized influenza virus hemagglutinin fusion glycoprotein system. (mdpi.com)
  • The best-studied example is fusion mediated by hemagglutinin (HA) of influenza virus. (asm.org)
  • In the model, the hemagglutinin molecules on a virus particle are activated at random to insert into the cell membrane. (elifesciences.org)
  • This approach shows that a substantial fraction of hemagglutinin molecules fail to contact the target-cell membrane and are permanently inactivated instead. (elifesciences.org)
  • Chen, J., Skehel, J.J. and Wiley, D.C. (1999) N- and C-terminal residues combine in the fusion-pH influenza hemagglutinin HA(2) subunit to form an N cap that ter-minates the triple-stranded coiled coil. (scirp.org)
  • These results give support for a model in which the E1 trimeric structure is involved in the SFV-mediated fusion reaction. (asm.org)
  • One difference was the prolonged Ca2+ influx exhibited by ybt1Δ vacuoles at the start of the fusion reaction. (illinois.edu)
  • B ) Scheme for simulation of fusion reaction. (elifesciences.org)
  • Flaviviruses infect their host cells by a membrane fusion reaction. (microbiologyresearch.org)
  • Thus, the phenotype of Deltaprm1 mutants defines a new step in the mating reaction in which membranes are juxtaposed, possibly through a defined adherence junction, yet remain unfused. (ucsf.edu)
  • The enveloped alphavirus, Semliki Forest virus (SFV), infects cells via endocytosis followed by a membrane fusion reaction triggered by the acid pH present in intracellular vacuoles. (elsevier.com)
  • First, the fusion reaction was synchronized by pre-incubating the viruses with cells at reduced temperature to allow CD4 and coreceptors engagement, but not the virus uptake or fusion. (biomedcentral.com)
  • Chakraborty H, Tarafdar PK, Bruno MJ, Sengupta T, Lentz BR (2012) Activation thermodynamics of poly(ethylene glycol)-mediated model membrane fusion support mechanistic models of stalk and pore formation. (springer.com)
  • This velocity indicates that the initial formation of a single fusion neck can be completed in a few hundred nanoseconds. (nanowerk.com)
  • Such a pulse leads to the formation of membrane pores in the opposing membranes, which subsequently fuse in order to dispose of the edges of the pores. (nanowerk.com)
  • This implies that the fusion neck has an average expansion velocity of centimetres per second and that the initial formation of the fusion neck can be completed within about 200 nanoseconds. (nanowerk.com)
  • Class-I PI3-kinases are needed for pronuclear envelope formation and fusion in sea urchin zygotes, and Rab7 GTPase and PtdIns(3,4,5) P 3 directly interact during the membrane fusion process. (biologists.org)
  • HIV-1 induces the fusion of uninfected CD4 + CXCR4/CCR5 + cells and infected cells expressing Env, resulting in the formation of giant multinucleated cells, termed syncytia. (jimmunol.org)
  • Tetraspanins are also involved in membrane fusion events such as sperm-oocyte fusion ( 20 ), myotube formation ( 21 ), and fusion of mononuclear phagocytes ( 22 ). (jimmunol.org)
  • Vesicle fusion results in formation of Tb 3+ /DPA chelates that are ~10,000 times more fluorescent than free Tb 3+ ( Figure 2 ). (thermofisher.com)
  • Time course studies show that both E1 trimer formation and fusion are fast processes, occurring in seconds. (asm.org)
  • Activation thermodynamics of poly(ethylene glycol)-mediated model membrane fusion support mechanistic models of stalk and pore formation. (sigmaaldrich.com)
  • GLUT4 is retained by an intracellular cycle of vesicle formation and fusion with endosomes. (semanticscholar.org)
  • A unique feature of homotypic lysosome fusion is the formation of IntraLumenal Fragments (ILF), whereby portions of the membranes are internalized and degraded upon merging. (concordia.ca)
  • Knocking out YCK3 stabilizes Vps41 and HOPS on membranes restoring fusion defects and ILF formation. (concordia.ca)
  • Fusion of germlings and hyphae is required for the formation of the interconnected mycelial network characteristic of filamentous fungi. (escholarship.org)
  • In both postulates, release is dependent on formation of ion permeability channels through the hydrophobic centers of the membranes. (elsevier.com)
  • This is an attractive model system for studying fusion because the key components are known, and the process has been reconstituted in vitro in a cell-free system and can be assessed in vivo . (nature.com)
  • Whereas both membrane fusion (in exocytosis or cell fusion) and fission (in endocytic processes) require initial membrane apposition and membrane dissolution, membrane fusion and fission are mechanistically and molecularly distinct processes. (pnas.org)
  • Common themes are emerging from the study of viral, cell-cell, intracellular, and liposome fusion. (sciencemag.org)
  • Viruses undergo dramatic structural reorganizations at many critical stages of their life cycles including during host cell invasion, membrane fusion, genome expulsion, assembly, and cell egress. (washington.edu)
  • This finding deals with one of the most fundamental reactions in a cell, how membranes fuse with each other. (innovations-report.com)
  • Why exactly does the cell membrane become more fluid in higher temperatures than lower? (physicsforums.com)
  • First, consider what generates the membrane potential- the 'battery' of a cell. (physicsforums.com)
  • What this means is that the ion concentrations within the cytosol (or equivalently, the ion gradients across the cell membrane) are set by how much energy can be extracted from hydrolyzing a molecule of ATP. (physicsforums.com)
  • In other cell types, such as the model Vero cell line, fusion occurs immediately following attachment at the cell surface in a pH-neutral manner ( Wittels and Spear, 1991 ). (frontiersin.org)
  • Herpes simplex virus is encased in a lipid bilayer envelope that is derived from internal membranes of the host cell. (frontiersin.org)
  • HA also mediates membrane fusion between the virus and a cell, which is the first critical step during infection. (harvard.edu)
  • Membrane fusion is the critical step for infectious cell penetration by enveloped viruses. (harvard.edu)
  • Therefore, the role of CD81 and other related tetraspanin, CD9, on the cell-to-cell fusion process mediated by HIV-1 was studied. (jimmunol.org)
  • Cell-to-cell fusion represents another way of virus spreading with the advantage of being inaccessible to humoral immune response ( 7 , 8 , 9 , 10 ). (jimmunol.org)
  • Virus-cell and cell-to-cell fusion processes are not fully understood. (jimmunol.org)
  • Plasmids expressing PrV glycoproteins under control of the immediate-early 1 promoter-enhancer of human cytomegalovirus were transfected into rabbit kidney cells, and the extent of cell fusion was quantitated 27 to 42 h after transfection. (asm.org)
  • Virus-cell fusion events mediated by viral membrane glycoproteins constitute a crucial primary step in the infectious cycle of all enveloped viruses. (asm.org)
  • We hypothesized that such fusogens were induced by mating pheromone and transported to the cell-cell fusion sites. (rice.edu)
  • The final step in the entry process is the fusion of the membrane that surrounds the influenza virus with the membrane of the host cell. (elifesciences.org)
  • By fluorescence and live-cell imaging we show that GFP-tagged PEF1 accumulates at the sites of membrane injury in a Ca 2+ -dependent manner. (genetics.org)
  • Mapping the water molecules is key to understanding the process of cell membrane fusion, which could help facilitate the development of treatments for diseases associated with cell fusion. (phys.org)
  • Using neutron diffraction at the Department of Energy's Oak Ridge National Laboratory, researchers have made the first direct observations of water in lipid bilayers used to model cell membrane fusion. (phys.org)
  • The research, published in Journal of Physical Chemistry Letters , could provide new insights into diseases in which normal cell fusion is disrupted, such as Albers-Schönberg disease (osteopetrosis), help facilitate the development of fusion-based cell therapies for degenerative diseases, and lead to treatments that prevent cell-to-cell fusion between cancer cells and non-cancer cells. (phys.org)
  • The envelope glycoprotein (E) is the membrane fusogen required for cell entry and infection ( Harrison, 2015 ). (elifesciences.org)
  • Assembly of cell plate-associated ER is likely to involve homotypic fusion of ER membrane within the division plane. (plantphysiol.org)
  • This interpretation was tested using both trans-cell dye diffusion and fusion pore conductivity measurements in cholesterol-enriched cells. (rupress.org)
  • The results of this study support the hypothesis that host cell cholesterol acts at two stages in membrane fusion: (1) early, prior to fusion pore opening, and (2) late, during fusion pore expansion. (rupress.org)
  • Cholesterol is a major and vital constituent of eukaryotic cell membranes. (rupress.org)
  • SARS-CoV-2 infection is initiated by virus binding to ACE2 cell surface receptors1-4, followed by fusion of virus and cell membranes to release the virus genome into the cell. (crick.ac.uk)
  • One or two glycoproteins that provide cell binding and membrane fusion are sufficient to mediate entry of many enveloped viruses [2] . (prolekare.cz)
  • Cell fusion occurs throughout development, from fertilization to organogenesis. (ucsf.edu)
  • Prm1p localizes to sites of cell-cell contact where fusion occurs. (ucsf.edu)
  • We show that deletion of FIG 1, which controls pheromone-induced Ca(2+) influx, yields similar cell fusion defects. (ucsf.edu)
  • Although extracellular Ca(2+) is not required for efficient cell fusion of wild-type cells, cell fusion in prm1 mutant mating pairs is dramatically reduced when Ca(2+) is removed. (ucsf.edu)
  • In the filamentous fungus Neurospora crassa, cell fusion occurs during asexual spore germination, where genetically identical germlings show chemotropic interactions and cell-cell fusion. (escholarship.org)
  • The involvement of Schizosaccharomyces pombe prm1(+) in cell fusion during mating and its relationship with other genes required for this process have been addressed. (ox.ac.uk)
  • Subsequent shift to a physiological temperature triggered accelerated virus uptake followed by entry from endosomes, but did not permit fusion at the cell surface. (biomedcentral.com)
  • Our results further support the notion that HIV-1 enters disparate cell types through fusion with endosomes. (biomedcentral.com)
  • Through these changes, the virus is able to target the cell membrane and approach it for virus-cell membrane fusion. (embopress.org)
  • Regardless of the complexity of the system, fusion essentially occurs due to the interplay of various interfacial forces, namely hydration repulsion, hydrophobic attraction and van der Waals forces. (wikipedia.org)
  • Fusion of two opposing membranes occurs in a wide range of processes. (rice.edu)
  • Intracellular membrane fusion occurs with exquisite coordination and specificity. (biologists.org)
  • In Saccharomyces cerevisiae, homotypic vacuole fusion occurs in experimentally defined phases. (illinois.edu)
  • Furthermore detailed analysis of the fusion kinetics between fluorescently labeled PM and proteo-liposomes containing either, pure P /rds , pure ROM-1 or the ROM-1-P /rds complex clearly demonstrated that optimal fusion requires an ROM-1/P/ rds complex. (ovid.com)
  • By changing the contact pressure one can access fusion kinetics and to some extent reconstruct the energy landscape of membrane fusion. (springer.com)
  • Optimal fusion kinetics were observed at pH 6.3, the threshold for fusion being pH 6.9. (microbiologyresearch.org)
  • Membrane fusion of Semliki Forest virus in a model system: correlation between fusion kinetics and structural changes in the envelope glycoprotein. (microbiologyresearch.org)
  • We have characterized these transitions by analyzing low-pH-induced fusion kinetics of individual virions and validated the analysis by computer simulation. (edu.au)
  • Time-lapse microscopy reveals that fusion and lysis events initiate with identical kinetics, suggesting that both outcomes result from engagement of the fusion machinery. (ucsf.edu)
  • The observation of the stalk structure supports the stalk hypothesis for membrane fusion and enables the measurement of these parameters experimentally. (sciencemag.org)
  • A test for the stalk hypothesis of membrane fusion. (springer.com)
  • These studies provide further support for the hypothesis that a P /rds dependent membrane fusion complex is involved in photoreceptor renewal processes. (ovid.com)
  • Here we show that the fusion step is retarded by the inhibition of phosphatidylinositol (PI) 3-kinase. (semanticscholar.org)
  • The widely accepted model for membrane fusion suggests that there is an intermediate state in which the two contacting monolayers become continuous via an hourglass-shaped structure called a stalk. (sciencemag.org)
  • Fusion intermediates are characterized by axial but not lateral confinement of the motion of the bead and independently by the change of its rate of diffusion due to the additional drag from the stalk-like connection between the two membranes. (utexas.edu)
  • Aeffner S, Reusch T, Weinhausen B, Salditt T (2012) Energetics of stalk intermediates in membrane fusion are controlled by lipid composition. (springer.com)
  • Abrams FS, London E (1993) Extension of the parallax analysis of membrane penetration depth to the polar region of model membranes: use of fluorescence quenching by a spin-label attached to the phospholipid polar headgroup. (springer.com)
  • pH-dependent fusion between the flavivirus West Nile and liposomal model membranes. (microbiologyresearch.org)
  • Furthermore, fusion processes are also crucial for the interactions between our cells and various pathogens such as viruses and bacteria. (nanowerk.com)
  • Occupation of this site by TBHQ stabilizes the neutral pH structure through intersubunit and intrasubunit interactions that presumably inhibit the conformational rearrangements required for membrane fusion. (rcsb.org)
  • Any downstream, effector interactions required for coupling Ca 2+ -bound synaptotagmin to vesicle fusion should cause as severe an effect as mutation of the C 2 B Ca 2+ -binding site itself. (jneurosci.org)
  • We further show that the membrane interacting region of Gc becomes structured only at acidic pH via a set of polar and electrostatic interactions. (pasteur.fr)
  • Here, we focus primarily on their role in exocytosis and organelle fusion. (biologists.org)
  • The process of membrane fusion is essential for the structure and dynamics of all cells in our bodies. (nanowerk.com)
  • Binding sites will be defined by competition assays, by identifying the amino acids that comprise the antibody epitopes, and by functional assays of the effects of antibodies in virus fusion. (elsevier.com)
  • Comparison of simulations with data from H3N2 and H1N1 viruses reveals three independent functional variables of HA-mediated membrane fusion closely linked to neutralization susceptibility. (harvard.edu)
  • which then cause fusion to take place in events such as fertilization, embryogenesis and even infections by various types of bacteria and viruses. (wikipedia.org)
  • Infection of cells with enveloped viruses is accomplished through membrane fusion. (asm.org)
  • For viruses, lipid rafts have been proposed to act at the stages of binding or fusion. (rupress.org)
  • Kinetic measurements of fusion combined with time-resolved imaging of single viruses further reinforced the notion that HIV-1 enters the cells via endocytosis and fusion with endosomes. (biomedcentral.com)
  • We found that deletion of YBT1 enhanced in vitro homotypic vacuole fusion by up to 50% relative to wild type vacuoles. (illinois.edu)
  • The intricate temporal and spatial regulation of membrane fusion is critical for all living organisms. (rice.edu)
  • Here we examined the role of Ycf1p and other ABCC transporters in the regulation of vacuole homotypic fusion. (illinois.edu)
  • Membrane fusion, essential to eukaryotic life, is broadly envisioned as a three-step process proceeding from contacting bilayers through two semistable, nonlamellar lipidic intermediate states to a fusion pore. (sigmaaldrich.com)
  • Enrichment of HAS cells with cholesterol reduced the delay between triggering and lipid dye transfer between HAS cells and human red blood cells (RBC), indicating that cholesterol facilitates membrane lipid mixing prior to fusion pore opening. (rupress.org)
  • Increased cholesterol also increased aqueous content transfer between HAS cells and RBC over a broad range of HA expression levels, suggesting that cholesterol also favors fusion pore expansion. (rupress.org)
  • Membrane fusion and targeting processes are tightly regulated and coordinated. (booktopia.com.au)
  • B) An example of fusion event, in which a vesicle was observed to undergo an LT to TT to F transition sequence. (ens.fr)
  • To facilitate intracellular membrane fusion reactions in a controlled manner, proteinaceous fusion machineries have evolved. (portlandpress.com)
  • The nature of the binding site suggests routes for the chemical modification of TBHQ that could lead to the development of more potent inhibitors of membrane fusion and potential anti-influenza drugs. (rcsb.org)
  • Now, Ivanovic and Harrison - two of the researchers from the earlier work - compared the predictions of this model to experimental data from previous studies of membrane fusion by influenza virus particles. (elifesciences.org)
  • Influenza-virus membrane fusion by cooperative fold-back of stochastic" by Tijana Ivanovic, Jason L. Choi et al. (edu.au)
  • Fusion of the lipid bilayers is induced by bringing an optically trapped bead in contact with the coverslip surface while observing the bead's thermal motion with microsecond temporal and nanometer spatial resolution using a three-dimensional position detector. (utexas.edu)
  • Illustration of neutron diffraction data showing water distribution (red and white molecules) near lipid bilayers prior to fusion (left) and during fusion. (phys.org)
  • When two cells combine during fertilization, or a membrane-bound vesicle fuses during viral entry, neuron signaling, placental development and many other physiological functions, the semi-permeable membrane bilayers between the fusing partners must be merged to exchange their internal contents. (phys.org)
  • As a postdoctoral fellow in the laboratory of Harden McConnell at Stanford University (1982-1984), Lukas Tamm originated the development of supported bilayers as a new model membrane system and co-discovered lipid domains in monolayers at the air-water interface. (umich.edu)
  • These results suggest that there are at least two distinct membrane fusion pathways involving Cdc48p/p97 and Sec18p/NSF that operate at the division plane to mediate plant cytokinesis. (plantphysiol.org)