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.
Fusion of somatic cells in vitro or in vivo, which results in somatic cell hybridization.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
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.
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.
Proteins that catalyze MEMBRANE FUSION.
Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.
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.
The entering of cells by viruses following VIRUS ATTACHMENT. This is achieved by ENDOCYTOSIS, by direct MEMBRANE FUSION of the viral membrane with the CELL MEMBRANE, or by translocation of the whole virus across the cell membrane.
Artificially produced membranes, such as semipermeable membranes used in artificial kidney dialysis (RENAL DIALYSIS), monomolecular and bimolecular membranes used as models to simulate biological CELL MEMBRANES. These membranes are also used in the process of GUIDED TISSUE REGENERATION.
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).
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.
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.
A broad category of proteins involved in the formation, transport and dissolution of TRANSPORT VESICLES. They play a role in the intracellular transport of molecules contained within membrane vesicles. Vesicular transport proteins are distinguished from MEMBRANE TRANSPORT PROTEINS, which move molecules across membranes, by the mode in which the molecules are transported.
A subfamily of Q-SNARE PROTEINS which occupy the same position as syntaxin 1A in the SNARE complex and which also are most similar to syntaxin 1A in their AMINO ACID SEQUENCE. This subfamily is also known as the syntaxins, although a few so called syntaxins are Qc-SNARES.
The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Cellular release of material within membrane-limited vesicles by fusion of the vesicles with the CELL MEMBRANE.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
Layers of protein which surround the capsid in animal viruses with tubular nucleocapsids. The envelope consists of an inner layer of lipids and virus specified proteins also called membrane or matrix proteins. The outer layer consists of one or more types of morphological subunits called peplomers which project from the viral envelope; this layer always consists of glycoproteins.
Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.
Established cell cultures that have the potential to propagate indefinitely.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.
Glycoproteins found on the membrane or surface of cells.
Operative immobilization or ankylosis of two or more vertebrae by fusion of the vertebral bodies with a short bone graft or often with diskectomy or laminectomy. (From Blauvelt & Nelson, A Manual of Orthopaedic Terminology, 5th ed, p236; Dorland, 28th ed)
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
A ubiquitous target SNARE protein that interacts with SYNTAXIN and SYNAPTOBREVIN. It is a core component of the machinery for intracellular MEMBRANE FUSION. The sequence contains 2 SNARE domains, one is the prototype for the Qb-SNARES, and the other is the prototype for the Qc-SNARES.
The GENETIC RECOMBINATION of the parts of two or more GENES resulting in a gene with different or additional regulatory regions, or a new chimeric gene product. ONCOGENE FUSION includes an ONCOGENE as at least one of the fusion partners and such gene fusions are often detected in neoplastic cells and are transcribed into ONCOGENE FUSION PROTEINS. ARTIFICIAL GENE FUSION is carried out in vitro by RECOMBINANT DNA technology.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
A darkly stained mat-like EXTRACELLULAR MATRIX (ECM) that separates cell layers, such as EPITHELIUM from ENDOTHELIUM or a layer of CONNECTIVE TISSUE. The ECM layer that supports an overlying EPITHELIUM or ENDOTHELIUM is called basal lamina. Basement membrane (BM) can be formed by the fusion of either two adjacent basal laminae or a basal lamina with an adjacent reticular lamina of connective tissue. BM, composed mainly of TYPE IV COLLAGEN; glycoprotein LAMININ; and PROTEOGLYCAN, provides barriers as well as channels between interacting cell layers.
SNARE proteins where the central amino acid residue of the SNARE motif is an ARGININE. They are classified separately from the Q-SNARE PROTEINS where the central amino acid residue of the SNARE motif is a GLUTAMINE. This subfamily contains the vesicle associated membrane proteins (VAMPs) based on similarity to the prototype for the R-SNAREs, VAMP2 (synaptobrevin 2).
An annexin family member that plays a role in MEMBRANE FUSION and signaling via VOLTAGE-DEPENDENT CALCIUM CHANNELS.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
ATPases that are members of the AAA protein superfamily (ATPase family Associated with various cellular Activities). The NSFs functions, acting in conjunction with SOLUBLE NSF ATTACHMENT PROTEINS (i.e. SNAPs, which have no relation to SNAP 25), are to dissociate SNARE complexes.
A family of proteins involved in intracellular membrane trafficking. They interact with SYNTAXINS and play important roles in vesicular docking and fusion during EXOCYTOSIS. Their name derives from the fact that they are related to Unc-18 protein, C elegans.
SNARE binding proteins that facilitate the ATP hydrolysis-driven dissociation of the SNARE complex. They are required for the binding of N-ETHYLMALEIMIDE-SENSITIVE PROTEIN (NSF) to the SNARE complex which also stimulates the ATPASE activity of NSF. They are unrelated structurally to SNAP-25 PROTEIN.
Multinucleated masses produced by the fusion of many cells; often associated with viral infections. In AIDS, they are induced when the envelope glycoprotein of the HIV virus binds to the CD4 antigen of uninfected neighboring T4 cells. The resulting syncytium leads to cell death and thus may account for the cytopathic effect of the virus.
Transmembrane envelope protein of the HUMAN IMMUNODEFICIENCY VIRUS which is encoded by the HIV env gene. It has a molecular weight of 41,000 and is glycosylated. The N-terminal part of gp41 is thought to be involved in CELL FUSION with the CD4 ANTIGENS of T4 LYMPHOCYTES, leading to syncytial formation. Gp41 is one of the most common HIV antigens detected by IMMUNOBLOTTING.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
A neuronal cell membrane protein that combines with SNAP-25 and SYNAPTOBREVIN 2 to form a SNARE complex that leads to EXOCYTOSIS.
The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.
Any spaces or cavities within a cell. They may function in digestion, storage, secretion, or excretion.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
Membrane proteins whose primary function is to facilitate the transport of molecules across a biological membrane. Included in this broad category are proteins involved in active transport (BIOLOGICAL TRANSPORT, ACTIVE), facilitated transport and ION CHANNELS.
Membrane glycoproteins from influenza viruses which are involved in hemagglutination, virus attachment, and envelope fusion. Fourteen distinct subtypes of HA glycoproteins and nine of NA glycoproteins have been identified from INFLUENZA A VIRUS; no subtypes have been identified for Influenza B or Influenza C viruses.
A subfamily of Q-SNARE PROTEINS which occupy the same position in the SNARE complex as the C-terminal SNARE domain of SNAP-25 and which also are most similar to the C-terminal region of SNAP-25 in their AMINO ACID SEQUENCE.
Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.
A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.
Preparation for electron microscopy of minute replicas of exposed surfaces of the cell which have been ruptured in the frozen state. The specimen is frozen, then cleaved under high vacuum at the same temperature. The exposed surface is shadowed with carbon and platinum and coated with carbon to obtain a carbon replica.
The two lipoprotein layers in the MITOCHONDRION. The outer membrane encloses the entire mitochondrion and contains channels with TRANSPORT PROTEINS to move molecules and ions in and out of the organelle. The inner membrane folds into cristae and contains many ENZYMES important to cell METABOLISM and energy production (MITOCHONDRIAL ATP SYNTHASE).
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
A synaptic membrane protein involved in MEMBRANE FUSION of SYNAPTIC VESICLES with the presynaptic membranes. It is the prototype member of the R-SNARE PROTEINS.
A subfamily of Q-SNARE PROTEINS which occupy the same position in the SNARE complex as the N-terminal SNARE domain of SNAP-25 and which also are most similar to the N-terminal region of SNAP-25 in their AMINO ACID SEQUENCE.
Transport proteins that carry specific substances in the blood or across cell membranes.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
The GENETIC TRANSLATION products of the fusion between an ONCOGENE and another gene. The latter may be of viral or cellular origin.
A species of CERCOPITHECUS containing three subspecies: C. tantalus, C. pygerythrus, and C. sabeus. They are found in the forests and savannah of Africa. The African green monkey (C. pygerythrus) is the natural host of SIMIAN IMMUNODEFICIENCY VIRUS and is used in AIDS research.
A stack of flattened vesicles that functions in posttranslational processing and sorting of proteins, receiving them from the rough ENDOPLASMIC RETICULUM and directing them to secretory vesicles, LYSOSOMES, or the CELL MEMBRANE. The movement of proteins takes place by transfer vesicles that bud off from the rough endoplasmic reticulum or Golgi apparatus and fuse with the Golgi, lysosomes or cell membrane. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990)
A species of ALPHAVIRUS isolated in central, eastern, and southern Africa.
Cytoplasmic vesicles formed when COATED VESICLES shed their CLATHRIN coat. Endosomes internalize macromolecules bound by receptors on the cell surface.
Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a choline moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and choline and 2 moles of fatty acids.
Specific hemagglutinin subtypes encoded by VIRUSES.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.
Cell membranes associated with synapses. Both presynaptic and postsynaptic membranes are included along with their integral or tightly associated specializations for the release or reception of transmitters.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.
The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.
A system of cisternae in the CYTOPLASM of many cells. In places the endoplasmic reticulum is continuous with the plasma membrane (CELL MEMBRANE) or outer membrane of the nuclear envelope. If the outer surfaces of the endoplasmic reticulum membranes are coated with ribosomes, the endoplasmic reticulum is said to be rough-surfaced (ENDOPLASMIC RETICULUM, ROUGH); otherwise it is said to be smooth-surfaced (ENDOPLASMIC RETICULUM, SMOOTH). (King & Stansfield, A Dictionary of Genetics, 4th ed)
Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to an ethanolamine moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and ethanolamine and 2 moles of fatty acids.
The rate dynamics in chemical or physical systems.
The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
Specific molecular components of the cell capable of recognizing and interacting with a virus, and which, after binding it, are capable of generating some signal that initiates the chain of events leading to the biological response.
Vesicles derived from the GOLGI APPARATUS containing material to be released at the cell surface.
Proteins found in any species of bacterium.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
Vesicles that are involved in shuttling cargo from the interior of the cell to the cell surface, from the cell surface to the interior, across the cell or around the cell to various locations.
Protein analogs and derivatives of the Aequorea victoria green fluorescent protein that emit light (FLUORESCENCE) when excited with ULTRAVIOLET RAYS. They are used in REPORTER GENES in doing GENETIC TECHNIQUES. Numerous mutants have been made to emit other colors or be sensitive to pH.
A family of vesicular transport proteins characterized by an N-terminal transmembrane region and two C-terminal calcium-binding domains.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Proteins prepared by recombinant DNA technology.
Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a serine moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and serine and 2 moles of fatty acids.
Proteins obtained from the species SACCHAROMYCES CEREVISIAE. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.
Inhibitors of the fusion of HIV to host cells, preventing viral entry. This includes compounds that block attachment of HIV ENVELOPE PROTEIN GP120 to CD4 RECEPTORS.
Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
A large family of MONOMERIC GTP-BINDING PROTEINS that play a key role in cellular secretory and endocytic pathways. EC 3.6.1.-.
A light microscopic technique in which only a small spot is illuminated and observed at a time. An image is constructed through point-by-point scanning of the field in this manner. Light sources may be conventional or laser, and fluorescence or transmitted observations are possible.
A genus of ciliate protozoa that is often large enough to be seen by the naked eye. Paramecia are commonly used in genetic, cytological, and other research.
Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.
A CELL LINE derived from the kidney of the African green (vervet) monkey, (CERCOPITHECUS AETHIOPS) used primarily in virus replication studies and plaque assays.
The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)
A species of ARENAVIRUS, part of the New World Arenaviruses (ARENAVIRUSES, NEW WORLD), causing Argentinian hemorrhagic fever. The disease is characterized by congestion, edema, generalized lymphadenopathy and hemorrhagic necrosis and is sometimes fatal.
Single membrane vesicles, generally made of PHOSPHOLIPIDS.
A family of RNA viruses causing INFLUENZA and other diseases. There are five recognized genera: INFLUENZAVIRUS A; INFLUENZAVIRUS B; INFLUENZAVIRUS C; ISAVIRUS; and THOGOTOVIRUS.
Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.
The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.
Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.
Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.
Elements of limited time intervals, contributing to particular results or situations.
A vesicular transport protein expressed predominately in NEURONS. Synaptotagmin helps regulate EXOCYTOSIS of SYNAPTIC VESICLES and appears to serve as a calcium sensor to trigger NEUROTRANSMITTER release. It also acts as a nerve cell receptor for certain BOTULINUM TOXINS.
Condensed areas of cellular material that may be bounded by a membrane.
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
Biological properties, processes, and activities of VIRUSES.
The cap-like structure covering the anterior portion of SPERM HEAD. Acrosome, derived from LYSOSOMES, is a membrane-bound organelle that contains the required hydrolytic and proteolytic enzymes necessary for sperm penetration of the egg in FERTILIZATION.
Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties.
Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.
CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.
Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.
CELL LINES derived from the CV-1 cell line by transformation with a replication origin defective mutant of SV40 VIRUS, which codes for wild type large T antigen (ANTIGENS, POLYOMAVIRUS TRANSFORMING). They are used for transfection and cloning. (The CV-1 cell line was derived from the kidney of an adult male African green monkey (CERCOPITHECUS AETHIOPS).)
The binding of virus particles to receptors on the host cell surface. For enveloped viruses, the virion ligand is usually a surface glycoprotein as is the cellular receptor. For non-enveloped viruses, the virus CAPSID serves as the ligand.
The infective system of a virus, composed of the viral genome, a protein core, and a protein coat called a capsid, which may be naked or enclosed in a lipoprotein envelope called the peplos.
Retroviral proteins, often glycosylated, coded by the envelope (env) gene. They are usually synthesized as protein precursors (POLYPROTEINS) and later cleaved into the final viral envelope glycoproteins by a viral protease.
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
The naturally occurring or experimentally induced replacement of one or more AMINO ACIDS in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish, enhance, or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties.
The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.
The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Protein-digesting and milk-clotting enzymes found in PINEAPPLE fruit juice and stem tissue. Enzymes from the two sources are distinguished as fruit bromelain and stem bromelain. This enzyme was formerly listed as EC
Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.
Enzymes that hydrolyze GTP to GDP. EC 3.6.1.-.
Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)
A class of morphologically heterogeneous cytoplasmic particles in animal and plant tissues characterized by their content of hydrolytic enzymes and the structure-linked latency of these enzymes. The intracellular functions of lysosomes depend on their lytic potential. The single unit membrane of the lysosome acts as a barrier between the enzymes enclosed in the lysosome and the external substrate. The activity of the enzymes contained in lysosomes is limited or nil unless the vesicle in which they are enclosed is ruptured. Such rupture is supposed to be under metabolic (hormonal) control. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
The characteristic three-dimensional shape of a molecule.
Proteins which are involved in the phenomenon of light emission in living systems. Included are the "enzymatic" and "non-enzymatic" types of system with or without the presence of oxygen or co-factors.
The sum of the weight of all the atoms in a molecule.
Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.
Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.
Glycoprotein from Sendai, para-influenza, Newcastle Disease, and other viruses that participates in binding the virus to cell-surface receptors. The HN protein possesses both hemagglutinin and neuraminidase activity.
The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.
Components of a cell produced by various separation techniques which, though they disrupt the delicate anatomy of a cell, preserve the structure and physiology of its functioning constituents for biochemical and ultrastructural analysis. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p163)
The assembly of the QUATERNARY PROTEIN STRUCTURE of multimeric proteins (MULTIPROTEIN COMPLEXES) from their composite PROTEIN SUBUNITS.
The type species of LENTIVIRUS and the etiologic agent of AIDS. It is characterized by its cytopathic effect and affinity for the T4-lymphocyte.
Microscopy in which the samples are first stained immunocytochemically and then examined using an electron microscope. Immunoelectron microscopy is used extensively in diagnostic virology as part of very sensitive immunoassays.
Measurement of the intensity and quality of fluorescence.
The membrane system of the CELL NUCLEUS that surrounds the nucleoplasm. It consists of two concentric membranes separated by the perinuclear space. The structures of the envelope where it opens to the cytoplasm are called the nuclear pores (NUCLEAR PORE).
Membrane-bound compartments which contain transmitter molecules. Synaptic vesicles are concentrated at presynaptic terminals. They actively sequester transmitter molecules from the cytoplasm. In at least some synapses, transmitter release occurs by fusion of these vesicles with the presynaptic membrane, followed by exocytosis of their contents.
The GENETIC RECOMBINATION of the parts of two or more GENES, including an ONCOGENE as at least one of the fusion partners. Such gene fusions are often detected in neoplastic cells and are transcribed into ONCOGENE FUSION PROTEINS.
Specific particles of membrane-bound organized living substances present in eukaryotic cells, such as the MITOCHONDRIA; the GOLGI APPARATUS; ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.
Proteins found in any species of virus.
A class I viral fusion protein that forms the characteristic spikes, or peplomers, found on the viral surface that mediate virus attachment, fusion, and entry into the host cell. During virus maturation, it is cleaved into two subunits: S1, which binds to receptors in the host cell, and S2, which mediates membrane fusion.
Interactive processes between the oocyte (OVUM) and the sperm (SPERMATOZOA) including sperm adhesion, ACROSOME REACTION, sperm penetration of the ZONA PELLUCIDA, and events leading to FERTILIZATION.
A genus of TOGAVIRIDAE, also known as Group A arboviruses, serologically related to each other but not to other Togaviridae. The viruses are transmitted by mosquitoes. The type species is the SINDBIS VIRUS.
The thermodynamic interaction between a substance and WATER.
Commonly observed structural components of proteins formed by simple combinations of adjacent secondary structures. A commonly observed structure may be composed of a CONSERVED SEQUENCE which can be represented by a CONSENSUS SEQUENCE.
Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.
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 species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.
A generic term for fats and lipoids, the alcohol-ether-soluble constituents of protoplasm, which are insoluble in water. They comprise the fats, fatty oils, essential oils, waxes, phospholipids, glycolipids, sulfolipids, aminolipids, chromolipids (lipochromes), and fatty acids. (Grant & Hackh's Chemical Dictionary, 5th ed)
The thin layers of tissue that surround the developing embryo. There are four extra-embryonic membranes commonly found in VERTEBRATES, such as REPTILES; BIRDS; and MAMMALS. They are the YOLK SAC, the ALLANTOIS, the AMNION, and the CHORION. These membranes provide protection and means to transport nutrients and wastes.
A species of HENIPAVIRUS, closely related to HENDRA VIRUS, which emerged in Peninsular Malaysia in 1998. It causes a severe febrile VIRAL ENCEPHALITIS in humans and also encephalitis and RESPIRATORY TRACT INFECTIONS in pigs. Fruit bats (PTEROPUS) are the natural host.
Mature male germ cells derived from SPERMATIDS. As spermatids move toward the lumen of the SEMINIFEROUS TUBULES, they undergo extensive structural changes including the loss of cytoplasm, condensation of CHROMATIN into the SPERM HEAD, formation of the ACROSOME cap, the SPERM MIDPIECE and the SPERM TAIL that provides motility.
A sulfhydryl reagent that is widely used in experimental biochemical studies.
A species of RESPIROVIRUS also called hemadsorption virus 2 (HA2), which causes laryngotracheitis in humans, especially children.
Nonionic surfactant mixtures varying in the number of repeating ethoxy (oxy-1,2-ethanediyl) groups. They are used as detergents, emulsifiers, wetting agents, defoaming agents, etc. Octoxynol-9, the compound with 9 repeating ethoxy groups, is a spermatocide.
The characteristic 3-dimensional shape and arrangement of multimeric proteins (aggregates of more than one polypeptide chain).
External envelope protein of the human immunodeficiency virus which is encoded by the HIV env gene. It has a molecular weight of 120 kDa and contains numerous glycosylation sites. Gp120 binds to cells expressing CD4 cell-surface antigens, most notably T4-lymphocytes and monocytes/macrophages. Gp120 has been shown to interfere with the normal function of CD4 and is at least partly responsible for the cytopathic effect of HIV.
Proteins found in any species of fungus.
Processes involved in the formation of TERTIARY PROTEIN STRUCTURE.
Antibodies produced by a single clone of cells.
Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.
The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.
The process by which two molecules of the same chemical composition form a condensation product or polymer.
55-kDa antigens found on HELPER-INDUCER T-LYMPHOCYTES and on a variety of other immune cell types. CD4 antigens are members of the immunoglobulin supergene family and are implicated as associative recognition elements in MAJOR HISTOCOMPATIBILITY COMPLEX class II-restricted immune responses. On T-lymphocytes they define the helper/inducer subset. CD4 antigens also serve as INTERLEUKIN-15 receptors and bind to the HIV receptors, binding directly to the HIV ENVELOPE PROTEIN GP120.
An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
A serine endopeptidase that is formed from TRYPSINOGEN in the pancreas. It is converted into its active form by ENTEROPEPTIDASE in the small intestine. It catalyzes hydrolysis of the carboxyl group of either arginine or lysine. EC
A phosphoinositide present in all eukaryotic cells, particularly in the plasma membrane. It is the major substrate for receptor-stimulated phosphoinositidase C, with the consequent formation of inositol 1,4,5-triphosphate and diacylglycerol, and probably also for receptor-stimulated inositol phospholipid 3-kinase. (Kendrew, The Encyclopedia of Molecular Biology, 1994)
Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.
Electron microscopy in which the ELECTRONS or their reaction products that pass down through the specimen are imaged below the plane of the specimen.
A subgroup of the genus FLAVIVIRUS that causes encephalitis and hemorrhagic fevers and is found in eastern and western Europe and the former Soviet Union. It is transmitted by TICKS and there is an associated milk-borne transmission from viremic cattle, goats, and sheep.
Immunologic method used for detecting or quantifying immunoreactive substances. The substance is identified by first immobilizing it by blotting onto a membrane and then tagging it with labeled antibodies.
Structures which are part of the CELL MEMBRANE or have cell membrane as a major part of their structure.
A general term for single-celled rounded fungi that reproduce by budding. Brewers' and bakers' yeasts are SACCHAROMYCES CEREVISIAE; therapeutic dried yeast is YEAST, DRIED.
Deletion of sequences of nucleic acids from the genetic material of an individual.
Regulatory proteins that act as molecular switches. They control a wide range of biological processes including: receptor signaling, intracellular signal transduction pathways, and protein synthesis. Their activity is regulated by factors that control their ability to bind to and hydrolyze GTP to GDP. EC 3.6.1.-.
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-limited structures derived from the plasma membrane or various intracellular membranes which function in storage, transport or metabolism.
A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.
Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with MYOSINS, actin is responsible for the contraction and relaxation of muscle.
Derivatives of PHOSPHATIDYLCHOLINES obtained by their partial hydrolysis which removes one of the fatty acid moieties.
A genetically related subfamily of RAB GTP-BINDING PROTEINS involved in transport from the cell membrane to early endosomes. This enzyme was formerly listed as EC
Guanosine 5'-(tetrahydrogen triphosphate). A guanine nucleotide containing three phosphate groups esterified to the sugar moiety.
A genus of the family Muridae consisting of eleven species. C. migratorius, the grey or Armenian hamster, and C. griseus, the Chinese hamster, are the two species used in biomedical research.
A fractionated cell extract that maintains a biological function. A subcellular fraction isolated by ultracentrifugation or other separation techniques must first be isolated so that a process can be studied free from all of the complex side reactions that occur in a cell. The cell-free system is therefore widely used in cell biology. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p166)
Protein-lipid combinations abundant in brain tissue, but also present in a wide variety of animal and plant tissues. In contrast to lipoproteins, they are insoluble in water, but soluble in a chloroform-methanol mixture. The protein moiety has a high content of hydrophobic amino acids. The associated lipids consist of a mixture of GLYCEROPHOSPHATES; CEREBROSIDES; and SULFOGLYCOSPHINGOLIPIDS; while lipoproteins contain PHOSPHOLIPIDS; CHOLESTEROL; and TRIGLYCERIDES.
Particles consisting of aggregates of molecules held loosely together by secondary bonds. The surface of micelles are usually comprised of amphiphatic compounds that are oriented in a way that minimizes the energy of interaction between the micelle and its environment. Liquids that contain large numbers of suspended micelles are referred to as EMULSIONS.
The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)
Cells that store epinephrine secretory vesicles. During times of stress, the nervous system signals the vesicles to secrete their hormonal content. Their name derives from their ability to stain a brownish color with chromic salts. Characteristically, they are located in the adrenal medulla and paraganglia (PARAGANGLIA, CHROMAFFIN) of the sympathetic nervous system.
Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.
The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.
Minute projections of cell membranes which greatly increase the surface area of the cell.
A member of the vesicle associated membrane protein family. It has a broad tissue distribution and is involved in MEMBRANE FUSION events of the endocytic pathways.

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.. ...
Your saved search Name of saved search: Search terms: Which day? Which day? Report format: Send at most: Send even when there arent any new results Optional text in email: Create a file for external citation management software dynamic stabilisation Best UK Spinal Clinic Surgeons Revolutionary treatments
MM-Tech is one of comprehensive manufacturer of Thermoplastic Welding Equipment and an experienced professional exporters in China. BUtt Fusion Machine,Socket Fusion Machine,Electrofusion Machine, Geomembrane welder.
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 [...]
The MTP Fusion Plate from TriMed is an anatomically contoured plate designed to give surgeons precise control over in-situ compression at the fusion site.
All of the presentations for Inclusion Fusion are available on-demand. Anyone who registers for the Web Summit will be able to access any presentation during Inclusion Fusion at any time during the conference. Each of the presentations has been pre-recorded. While most of our faculty will be available at designated times during the conference for…
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.
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 ...
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.. ...
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 ... Domain 1 contains the catalytic site for membrane fusion. Class IV fusion proteins, better known as fusion-associated small ... which encode products involved in driving membrane fusion. While adult somatic cells do not typically undergo membrane fusion ...
Random fusion can result in severe problems to the normal functioning of the human body. Fusion of biological membranes is ... Membrane fusion is a key biophysical process that is essential for the functioning of life itself. It is defined as the event ... In living beings, cells are made of an outer coat made of lipid bilayers; which then cause fusion to take place in events such ... biological phenomena including folding and stabilization of macromolecules such as proteins and fusion of cell membranes. The ...
Harrison, Stephen C. (May 2015). "Viral membrane fusion". Virology. 479-480: 498-507. doi:10.1016/j.virol.2015.03.043. PMC ... 33 Many spike proteins are membrane fusion proteins. Being exposed on the surface of the virion, spike proteins can be antigens ... Spike proteins are membrane proteins with typically large external ectodomains, a single transmembrane domain that anchors the ... S is a class I fusion protein and is responsible for mediating viral entry as the first step in viral infection. It is highly ...
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 ...
Furthermore, IFITM proteins reduced membrane fluidity and affected membrane curvature to restrict viral membrane fusion with ... IFITM proteins inhibit viral membrane and cellular endosomal or lysosomal vesicle membrane fusion by modifying their lipid ... which in turn blocks viral membrane and vesicle membrane fusion. GRCh38: Ensembl release 89: ENSG00000185885 - Ensembl, May ... Harrison, Stephen C (July 2008). "Viral membrane fusion". Nat Struct Mol Biol. 15 (7): 690-8. doi:10.1038/nsmb.1456. PMC ...
Morgan A, Burgoyne RD (November 2004). "Membrane traffic: controlling membrane fusion by modifying NSF". Current Biology. 14 ( ... as well as in the disassembly following a vesicle fusion event. Following membrane fusion, the tethering SNARE proteins complex ... The existence of these ATP primed vesicles for fusion at the pre-synaptic membrane is facilitated by the interactions of SNAP ... The suspected mechanism may involve priming of the SNARE-SNAP-NSF complex to increase vesicle fusion at the membranes, however ...
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 ...
Moss B (December 2016). "Membrane fusion during poxvirus entry". Seminars in Cell & Developmental Biology. 60: 89-96. doi: ... Protein synthesis allows for the ER membrane of the factory to dismantle, while small two lipid bilayer membranes will appear ... The monkeypox virus, like other poxviruses, is oval shaped, with a lipoprotein outer membrane. The outer membrane protects the ... Virus entry into the host cell plasma membrane is dependent on a neutral pH, otherwise entry occurs via a low-pH dependent ...
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 ... 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- ...
Receptor binding and membrane fusion. Attachment glycoprotein G is a tetrameric transmembrane domain protein that has a short ... All domains of the fusion protein are conserved by NiV, HeV, and GhV as the protein contains a fusion cleavage sequence, fusion ... The Fusion protein F is synthesized as an inactive precursor F0 form before being cleaved by cellular proteases into the active ... While HeV and NiV have strong fusion activity with a variety of host cells, GhV is restricted to a limited host range and only ...
... 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 ...
... 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: ...
Exosomes are released eventually due to fusion of this endosome with plasma membrane of cell. Hijacking of exosomal machinery ... This forces the vesicle membrane against the membrane of the target complex (or the outer membrane of the cell) and causes the ... Papahadjopoulos D, Nir S, Düzgünes N (April 1990). "Molecular mechanisms of calcium-induced membrane fusion". Journal of ... It takes place in the form of Golgi membrane-bound micro-sized vesicles, termed membrane vesicles (MVs). In this process, the ...
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 ...
VIR-576 is a synthesized peptide which binds to gp41, preventing fusion of the virus with a cell membrane. ITX5061 for ... Xiao, Tianshu; Cai, Yongfei; Chen, Bing (2021). "HIV-1 entry and membrane fusion inhibitors". Viruses. 13 (5): 735. doi:10.3390 ... Fusion Inhibitor Resource Center HIV+Fusion+Inhibitors at the US National Library of Medicine Medical Subject Headings (MeSH) ( ... which approximates the membrane of HIV and the T cell and promotes their fusion The entry of the viral core into the cell Entry ...
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". ... Kadam, Rameshwar U.; Wilson, Ian A. (2017). "Structural basis of influenza virus fusion inhibition by the antiviral drug ...
"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. Bibcode:2000Natur.407..194P. doi: ... 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. ...
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. ...
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 ...
F-protein, as other paramyxoviral fusion proteins, is a trimeric class I viral membrane fusion protein. It is produced in the ... uses host cellular membrane lipid bilayer for viral capsid membrane formation. Binding to a host cell membrane of viral ... Two of SeV proteins: HA and F, after their binding directly to a cellular membrane, promote a cell-cell fusion, which leads to ... This cleavage promotes the fusion of the viral lipid envelope with the cell outer membrane. In the lipid envelope of the virus ...
... encode proteins that bind a syntaxin protein and mediate synaptic vesicle membrane docking and fusion to the plasma membrane. ... Scales SJ, Chen YA, Yoo BY, Patel SM, Doung YC, Scheller RH (2000). "SNAREs contribute to the specificity of membrane fusion". ... While the protein is mostly membrane-bound, a significant fraction of it is found free in the cytoplasm. Use of multiple ... This gene, a member of the SNAP25 gene family, encodes a protein involved in multiple membrane trafficking steps. Two other ...
1992). "A multisubunit particle implicated in membrane fusion". J. Cell Biol. 117 (3): 531-8. doi:10.1083/jcb.117.3.531. PMC ... Prekeris R, Klumperman J, Chen YA, Scheller RH (1998). "Syntaxin 13 mediates cycling of plasma membrane proteins via ...
Nichols BJ, Pelham HR (Aug 1998). "SNAREs and membrane fusion in the Golgi apparatus". Biochimica et Biophysica Acta (BBA) - ... a novel essential factor for p97/p47-mediated membrane fusion, is required for Golgi and ER assembly in vivo". The Journal of ... "Distinct SNARE complexes mediating membrane fusion in Golgi transport based on combinatorial specificity". Proceedings of the ... "Implication of ZW10 in membrane trafficking between the endoplasmic reticulum and Golgi". The EMBO Journal. 23 (6): 1267-78. ...
1992). "A multisubunit particle implicated in membrane fusion". J. Cell Biol. 117 (3): 531-8. doi:10.1083/jcb.117.3.531. PMC ... NAPG mediates platelet exocytosis and controls the membrane fusion events of this process. GRCh38: Ensembl release 89: ... NSF and SNAPs (NSF attachment proteins) are general elements of the cellular membrane transport apparatus. The sequence of the ... 1992). "Soluble N-ethylmaleimide-sensitive fusion attachment proteins (SNAPs) bind to a multi-SNAP receptor complex in Golgi ...
"Mitelman Database of Chromosome Aberrations and Gene Fusions in Cancer". Retrieved 2018-11-27. Nathanson, ... "Oncogene Amplification in Growth Factor Signaling Pathways Renders Cancers Dependent on Membrane Lipid Remodeling". Cell ...
There are some examples of pitch which do not have an "edge" on the basilar membrane, which this would account for-e.g., white ... "Binaural pitch fusion: Comparison of normal-hearing and hearing-impaired listeners". The Journal of the Acoustical Society of ...
In five out of six occasions, pVII and pIX fusions without pelB was more efficient than pIII fusions in affinity selection ... Ff phages for phage display is that they require the protein of interest to be translocated across the bacterial inner membrane ... However, using pIII as the fusion partner can lead to a decrease in phage infectivity leading to problems such as selection ... In all cases, phage display levels were lower than using pIII fusion. However, lower display might be more favorable for the ...
... and from this point a fine platinized platinum wire extends through the lumen of the tube and is held in place by fusion to a ... life processes of cell membranes, the importance of pH control, the role of iodine in human health, and specifically its ...
... the ventral part of the cloacal membrane becomes the urogenital membrane. Mesoderm extends to the midventral line for some ... This fusion of the paramesonephric ducts begins in the third month, and the septum formed by their fused medial walls ... Even after differentiation can be seen between the sexes, some stages are common, e.g. the disappearing of the membrane. On the ... The remainder of the phallic portion is for a time tubular, and then, by the absorption of the urogenital membrane, it ...
Nd:glass lasers are usually frequency tripled to the third harmonic at 351 nm in laser fusion devices. Uranyl acetate has been ... Neodymium dust and salts are very irritating to the eyes and mucous membranes, and moderately irritating to skin. Breathing the ... These lasers have been used in extremely high-power applications, such as experiments in inertial confinement fusion. Neodymium ... multiple beam systems for inertial confinement fusion. ...
This causes the host cell membrane to protrude outward and invaginate the membrane of an adjacent cell. The bacteria are then ... For this reason, as well as to avoid phagolysosomal fusion and death, rickettsiae must escape from the phagosome. To escape ... This species of Rickettsia uses an abundant cell surface protein called OmpB to attach to a host cell membrane protein called ... "Rickettsial Outer-Membrane Protein B (rOmpB) Mediates Bacterial Invasion through Ku70 in an Actin, c-Cbl, Clathrin and Caveolin ...
The t(9;22) translocation results in the head-to-tail fusion of the BCR and ABL1 genes, leading to a fusion gene present in ... 3 domain-binding protein suggests a general mechanism of association of tyrosine kinases with the spectrin-based membrane ... This new fusion gene, BCR-ABL, encodes an unregulated, cytoplasm-targeted tyrosine kinase that allows the cells to proliferate ... This gene is a partner in a fusion gene with the BCR gene in the Philadelphia chromosome, a characteristic abnormality in ...
This is just as when water flow moves the rubber membrane, it increases the amount of water on one side of the membrane, and ... fusion research, and particle accelerators. Large capacitor banks (reservoir) are used as energy sources for the exploding- ... A capacitor is like a rubber membrane sealed inside a pipe. Water molecules cannot pass through the membrane, but some water ... The elasticity of the membrane is analogous to capacitance. A very stretchy, flexible membrane will expand more with a given ...
Pallavi, B.; Nagaraj, R. (2003). "Palmitoylated peptides from the cysteine- rich domain of SNAP-23 cause membrane fusion ... Sitaram, N.; Nagaraj, R. (1999). "Interaction of antimicrobial peptides with biological and model membranes: structural and ... "Interaction of synthetic peptides corresponding to the scaffolding domain of Caveolin-3 with model membranes". Biopolymers. 84 ...
S2 mediates the membrane fusion of the virus to its potential cell host via the H1 and HR2, which are heptad repeat regions. ... The largest droplets of respiratory fluid do not travel far, but can be inhaled or land on mucous membranes on the eyes, nose, ... The structural proteins of SARS-CoV-2 include membrane glycoprotein (M), envelope protein (E), nucleocapsid protein (N), and ...
Mitosis is immediately followed by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two ... these fusions are fragments that contain a nuclear localization signal and ubiquitination sites for degradation, but are not ...
Fusion of the viral envelope with the plasma membrane releases the viral core into the host cytoplasm. Expression of early- ... In this latter case, the virion is transported to the plasma membrane via microtubules. Natural hosts of orthopoxviruses are ... or can acquire a second membrane from the Golgi apparatus and bud as extracellular enveloped virions. ...
Whether the virus enters specifically through endocytosis or membrane fusion is still not known in all cases; it is believed to ... The virus is transported to the Golgi apparatus and subsequently released from the cell's membrane The effects infection has ... Glycoprotein complexes embedded within the viral envelope of these viruses attach to receptors within the host cell's membrane ... allowing the budding of the newly formed virus through the inner lamella of the nuclear membrane to begin. ...
In E. coli, DMSOR is embedded within the membrane and has three unique subunits, one of which includes the characteristic ... A study of lacZ fusions (reporter genes) to corresponding dorS, dorR, and dorC promoters concluded that expression of DorR and ...
Biomimetic interfaces comprised of S-layer proteins, lipid membranes and membrane proteins. J. R. Soc. Interface 11 (2014) ... S-layer fusion proteins - construction principles and applications. Curr. Opin. Biotech. 22(6) (2011) 824-831. Schuster, B., U. ... These results were also the basis for the production of large S-layer ultrafiltration membranes with strictly defined ... and lipid membranes including liposomes and emulsomes in the form of regular lattices. Due to their unique repetitive ...
Fusion of myoblasts generates myotubes, in a process linked to androgen receptor levels. Higher androgen levels lead to ... Androgens have also been found to signal through membrane androgen receptors, which are distinct from the classical nuclear ... Lang F, Alevizopoulos K, Stournaras C (2013). "Targeting membrane androgen receptors in tumors". Expert Opin. Ther. Targets. 17 ...
One model predicts that the vesicle undergoes complete fusion with the presynaptic cellular membrane once all its contents have ... It then must retrieve vesicular membrane from other sites which could take up to tens of seconds. The second model tries to ... Recycling of synaptic-vesicle membrane proteins is rapid, as indicated by the ability of many neurons to fire fifty times a ... as they do during endocytosis of plasma-membrane proteins in other cells (see Figure 17-46). Rather, the recycled vesicles are ...
... to a plasma membrane H+ gradient". The Journal of Biological Chemistry. 287 (43): 36239-50. doi:10.1074/jbc.M112.403550. PMC ... identification of Na+/H+ exchanger domain containing 2 and its role in osteoclast fusion". Proteomics. 8 (13): 2625-39. doi: ...
Huang H, Ball JM, Billheimer JT, Schroeder F (1999). "The sterol carrier protein-2 amino terminus: a membrane interaction ... evidence for a gene fusion in SCPx". DNA Cell Biol. 10 (9): 695-8. doi:10.1089/dna.1991.10.695. PMID 1755959. Schroeder F, ... 1995). "Sterol carrier protein-2 stimulates intermembrane sterol transfer by direct membrane interaction". Chem. Phys. Lipids. ...
In the nuclear fusion process, the nuclear content mix together after the dissolution of the membranes of each nucleus, and ... The invagination of the plasma membrane of ascus generates the two unit membranes that consist of the ascus vesicle. Then ... Following nuclear fusion, the oogonium expands and about three ascogenous hyphae would develop from it and give rise to asci ... The inner delimiting membrane became the primary wall with a consistent structure and no ornamentation. The ascospores would ...
v-Crk, a transforming oncoprotein from avian sarcoma viruses, is a fusion of viral "gag" protein with the SH2 and SH3 domains ... Abassi YA, Vuori K (2002). "Tyrosine 221 in Crk regulates adhesion-dependent membrane localization of Crk and Rac and ... 1996). "DOCK180, a major CRK-binding protein, alters cell morphology upon translocation to the cell membrane". Mol. Cell. Biol ... alters cell morphology upon translocation to the cell membrane". Mol. Cell. Biol. 16 (4): 1770-6. doi:10.1128/MCB.16.4.1770. ...
Under the microscope, scientists observed the virus enter the amoeba through fusion with membrane vacuoles, and integrate their ... Pandoravirus enters amoebas through phagocytic vacuoles, then fuses with the membrane vacuole of the amoeba. This leads to ...
Chodorge, M (3 December 2018). "Engineering of a GLP-1 analogue peptide/anti-PCSK9 antibody fusion for type 2 diabetes ... "Aquaporin-1 is expressed by vascular smooth muscle cells and mediates rapid water transport across vascular cell membranes". J ... 2019 Engineering of a GLP-1 analogue peptide/anti-PCSK9 antibody fusion for type 2 diabetes treatment, Sci Rep, 2018 A novel in ... 1999 Aquaporin-1 is expressed by vascular smooth muscle cells and mediates rapid water transport across vascular cell membranes ...
In fungi, the sexual fusion of haploid cells is called karyogamy. The result of karyogamy is the formation of a diploid cell ... first the nucleus of the parent divides into two and then the cell membrane also cleaves, becoming two "daughter" Amoebae. ... After approximately 30 hours from the time of fertilization, a fusion of the pronuclei and immediate mitotic division produce ...
TMPRSS2-ETS gene family fusion, specifically TMPRSS2-ERG or TMPRSS2-ETV1/4 promotes cancer cell growth. These fusions can arise ... Prostate-specific membrane antigen (PSMA) stimulates cancer development by increasing folate levels, helping the cancer cells ... As of 2011, MRI was used to identify targets for prostate biopsy using fusion MRI with ultrasound (US) or MRI-guidance alone. ... December 2009). "[Fusion genes and prostate cancer. From discovery to prognosis and therapeutic perspectives]". Progres en ...
... membrane glycoprotein - membrane protein - membrane topology - membrane transport - memory B cell - memory T cell - Mendelian ... fusion oncogene protein G protein - G protein-coupled receptor - G3P - GABA - GABA receptor - GABA-A receptor - gag-onc fusion ... cell membrane - cell membrane transport - cell nucleus - cell surface receptor - cellular respiration - cellulose - centriole ... plasma membrane - plasmid - plasmin - plasminogen - platelet glycoprotein GPIb-IX complex - platelet membrane glycoprotein - ...
The homodimeric tRNA-intron lyase, α′2 is composed of two α′ subunits that appear to be a fusion protein made up of two α ... "Precise excision of intervening sequences from precursor tRNAs by a membrane-associated yeast endonuclease". Cell. 32 (2): 525- ...
H. somni vaccines are usually killed cells or specific outer membrane proteins but have not been proven to be effective at ... "Histophilus somni Survives in Bovine Macrophages by Interfering with Phagosome-Lysosome Fusion but Requires IbpA for Optimal ... It has been suggested that pathogenesis begins when the bacteria invades and crosses the pulmonary alveolar membrane or that it ... Histophilus somni is a commensal bacteria of mucous membranes of the upper respiratory tract and reproductive tract with a ...
... on the surface of coronaviruses and are crucial for engagement of host cell receptors and the initiation of membrane fusion in ... "Pre-fusion structure of a human coronavirus spike protein". Nature. 531 (7592): 118-121. doi:10.1038/nature17200. ISSN 1476- ...
This thesis is concerned with studies on two aspects of membrane fusion. The first aspect is the mechanism of membrane fusion ... The conditions that favour hemi-fusion as opposed to complete fusion were characterised, and the possibility that hemi-fusion ... The second aspect is the mechanism of membrane fusion induced by fusogenic viral peptides. Evidence was found from both ... between the observed secondary structures and orientation of these fusion peptides and how they may induce membrane fusion are ...
Their ectodomains drive fusion by undergoing large-scale refolding, but little is known about the functionally important ... regions located within or near the membrane. Here we report the crystal structure of full-length glycoprotei … ... Viral fusogens merge viral and cell membranes during cell penetration. ... Structural basis for membrane anchoring and fusion regulation of the herpes simplex virus fusogen gB Nat Struct Mol Biol. 2018 ...
Here, we show that synthetic amphiphile membranes also undergo fusion, mediated by the protein machinery for synaptic secretion ... Here, the authors show that synthetic amphiphile membranes undergo SNARE-mediated fusion, and determine bending rigidity ... We determined bending rigidity and pore edge tension as key parameters for fusion and described its plausible progression ... Yet natural membranes are also dynamically remodeled in multiple cellular processes. ...
The complex mitochondrial network is the result of the two ongoing forces of fusion and fission of inner and outer membranes. ... They catalyze nucleotide-dependent membrane remodeling and are widely conserved from bacteria to higher eukaryotes. Although ... modeling in conjunction with biochemical data can be an asset in progressing the still challenging field of membrane dynamics. ... The complex mitochondrial network is the result of the two ongoing forces of fusion and fission of inner and outer membranes. ...
Role of Mechanical Properties of Cell Mediated Vesicles in Membrane Fusion. D. Vorselen, W.H. Roos, J.J.W.A. van Loon, G.J.L. ... Role of Mechanical Properties of Cell Mediated Vesicles in Membrane Fusion. / Vorselen, D.; Roos, W.H.; van Loon, J.J.W.A. et ... Role of Mechanical Properties of Cell Mediated Vesicles in Membrane Fusion. In: Biophysical Journal. 2013 ; Vol. 104, No. 2. pp ... Role of Mechanical Properties of Cell Mediated Vesicles in Membrane Fusion. Biophysical Journal. 2013;104(2):620A-620A. https ...
Bos1p, an integral membrane protein of the endoplasmic reticulum to golgi transport vesicles, is required for their fusion ... VAMP3/Syb and YKT6 are required for the fusion of constitutive secretory carriers with the plasma membrane. Plos Genetics 13(4 ... Myosin VI and its binding partner optineurin are involved in secretory vesicle fusion at the plasma membrane. Molecular Biology ... membrane protein 2 and acidic phospholipids may modulate the fusion of transport vesicles with the plasma membrane. Molecular ...
title = "Spatial regulation of membrane fusion controlled by modification of phosphoinositides",. abstract = "Membrane fusion ... facilitate fusion. However, the specific role of lipids in membrane fusion of natural membranes is not well established. ... facilitate fusion. However, the specific role of lipids in membrane fusion of natural membranes is not well established. ... facilitate fusion. However, the specific role of lipids in membrane fusion of natural membranes is not well established. ...
regulation of syncytium formation by plasma membrane fusion regulation of syncytium formation by plasma membrane fusion Show ... negative regulation of syncytium formation by plasma membrane fusion negative regulation of syncytium formation by plasma ... positive regulation of syncytium formation by plasma membrane fusion positive regulation of syncytium formation by plasma ... by the fusion of the plasma membranes of two or more individual cells. ...
Mechanisms of membrane fusion. Fasshauer, D., Schuette, C. G., & Jahn, R. (2001). Mechanisms of membrane fusion. B. I. F. ...
... the increase in vesicle membrane size or membrane growth to mimic cell growth could occur by vesicle-vesicle fusion initiated ... Rapid growth and fusion of protocells in surface-adhered membrane networks. Elif S. Köksal, Susanne Liese, Lin Xue, Ruslan ... The membrane component is essential, since bilayer membranes that surround all types of cells as we know them today are thought ... They observe fusion events on vesicles predominantly present on the same nanotube. However, they go on to identify the fusion ...
From this state the fusion pore could open again leading to the complex fusion behavior of a flickering fusion pore. In summary ... The fusion of neurotransmitter filled vesicles with the presynaptic membrane is the key step in the neuronal signaling cascade ... Simultaneous imaging of lipid dye diffusion from the PSM into the vesicular membrane via a fusion stalk was used to quantify ... The fusion pore formation was then directly visualized by imaging the transfer of SRB from inside the vesicle into the space ...
All structured data from the main, Property, Lexeme, and EntitySchema namespaces is available under the Creative Commons CC0 License; text in the other namespaces is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. ...
Membrane fusion process of Semliki Forest virus. I: Low pH-induced rearrangement in spike protein quaternary structure precedes ... Membrane fusion process of Semliki Forest virus. II: Cleavage-dependent reorganization of the spike protein complex controls ... A Salminen, J M Wahlberg, M Lobigs, P Liljeström, H Garoff; Membrane fusion process of Semliki Forest virus. II: Cleavage- ... Noninfectivity resulted from impaired uptake into cells, as well as from the inability of the virus to promote membrane fusion ...
... 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.[7][8] Class IV[edit]. Class IV fusion proteins, better known as ... Pathogenic viral fusion[edit]. Enveloped viruses readily overcome the thermodynamic barrier of merging two plasma membranes by ...
Thus, this novel defense strategy through proteasome-regulating membrane fusion of the vacuolar and plasma membranes provides ... Thus, this novel defense strategy through proteasome-regulating membrane fusion of the vacuolar and plasma membranes provides ... Thus, this novel defense strategy through proteasome-regulating membrane fusion of the vacuolar and plasma membranes provides ... Thus, this novel defense strategy through proteasome-regulating membrane fusion of the vacuolar and plasma membranes provides ...
... est loutil de référencementde la production scientifique de lULB.Linterface de recherche DI-fusion permet de consulter les ... DI-fusion, le Dépôt institutionnel numérique de lULB, ... Study of the drug-anionic lipid interactions in model membranes ... Recherche avancée , Historique de recherche Mon DI-fusion , À propos de DI-fusion , Contact , ... DI-fusion. * Lipid-protein interactions regulating the canonical and the non-canonical NLRP3 inflammasome par Pizzuto, Malvina ...
SNARE proteins are the core of the cells fusion machinery and mediate virtually all known intracellular membrane fusion ... SNARE proteins are the core of the cells fusion machinery and mediate virtually all known intracellular membrane fusion ... Fusion is catalyzed when vesicle-associated v-SNAREs form trans-SNARE complexes ("SNAREpins") with target membrane-associated t ... Entropic forces drive self-organization and membrane fusion by SNARE proteins [Biophysics and Computational Biology]. Erdem ...
p-KIAA1549-BRAF fusion dimer [plasma membrane] (Homo sapiens) * KIAA1549(1-1749)-p-BRAF(381-766) fusion [plasma membrane] (Homo ... p-KIAA1549-BRAF fusion dimer [plasma membrane] (Homo sapiens) * KIAA1549(1-1749)-p-BRAF(381-766) fusion [plasma membrane] (Homo ... p-KIAA1549-BRAF fusion dimer [plasma membrane] (Homo sapiens) * KIAA1549(1-1749)-p-BRAF(381-766) fusion [plasma membrane] (Homo ... p-KIAA1549-BRAF fusion dimer [plasma membrane] (Homo sapiens) * KIAA1549(1-1749)-p-BRAF(381-766) fusion [plasma membrane] (Homo ...
"Membrane Fusion" by people in this website by year, and whether "Membrane Fusion" was a major or minor topic of these ... The adherence and merging of cell membranes, intracellular membranes, or artificial membranes to each other or to viruses, ... "Membrane Fusion" is a descriptor in the National Library of Medicines controlled vocabulary thesaurus, MeSH (Medical Subject ... Below are the most recent publications written about "Membrane Fusion" by people in Profiles. ...
Microsurgery of Cell Membrane with Femtosecond Laser Pulses for Cell Fusion and Optical Injection Authors. * I.V. Ilina Joint ... Successfulpermeabilization of a cell membrane andoptoinjection of a membrane impermeable dye wasperformed with the help of a ... Laser-based cellfusion of mammalian embryo blastomeres as wellas fusion of cell bodies of neurons of molluskLymnaea stagnalis ... We report on results of using femtosecond laserscalpel for microsurgery of plasma membrane ofliving cells. Femtosecond laser ...
Enveloped viruses require fusion of the viral membrane with the host cell membrane for infection. This process involves the ... Blocking Virus-Cell Membrane Fusion. 7.3.1. Recombinant Human Angiotensin-converting Enzyme 2 (APN01). The soluble recombinant ... arbidol prevents the fusion of the viral membrane with the endosome after endocytosis. Currently, it is undergoing trials as a ... conformational change of the viral glycoprotein from the pre-fusion form to the post-fusion form. Although the pre-fusion ...
The inner workings of intracellular heterotypic and homotypic membrane fusion mechanisms. Autor : Cruz, Mariel Delgado. Kim, ... The inner workings of intracellular heterotypic and homotypic membrane fusion mechanisms. Journal of Biosciences. 2019 Sep; 44( ...
title = "A multisubunit particle implicated in membrane fusion",. abstract = "The N-ethylmaleimide sensitive fusion protein ( ... A multisubunit particle implicated in membrane fusion. / Wilson, D. W.; Whiteheart, S. W.; Wiedmann, M. et al. ... A multisubunit particle implicated in membrane fusion. Journal of Cell Biology. 1992;117(3):531-538. doi: 10.1083/jcb.117.3.531 ... A multisubunit particle implicated in membrane fusion. In: Journal of Cell Biology. 1992 ; Vol. 117, No. 3. pp. 531-538. ...
Quantitative Aspects of Membrane Fusion and Fission Monday, May 06, 2019 - Friday, May 10, 2019 ...
KEEN.DRY waterproof, breathable membrane * KEEN.FUSION rubber for lightweight durability * Lace-lock bungee system ... Waterproof Protection: KEEN.DRY waterproof membrane inside and PFAS-free water repellency outside keep feet dry. ... Infused with non-toxic vanilla fragrance during high-temp KEEN.FUSION bonding process ... A proprietary waterproof, breathable membrane that lets vapor out without letting water in. ...
Know the future scenario, forecast, and current trends in Fusion Splicer. ... The research insight on Fusion Splicer Market highlights the growth strategies of the companies. ... The fusion splicer market was valued at USD 570.5 Million in 2016 and is expected to reach USD 762.3 Million by 2022, at a CAGR ... Moreover, the fusion splicer market registered a shipment of 65,735 units in 2016 and is expected to reach 97,353 units by 2022 ...
MEMBRANE ACOUSTIC PANEL - Designer Sound absorbing room divider from OFFECCT ✓ all information ✓ high-resolution images ✓ CADs ... The components of Membrane will be produced in a mixture of recycled felt and plastic. It marks a successful first fusion ... Membrane filters sound waves and makes the sound in a room more balanced. One kit consists of 24 acoustic pieces including ... The design for Membrane derives from David Trubridges signature seed system in which a product is entirely made out of several ...
1a, gene 1a; 1b, gene 1b; S, spike protein gene; 3abc, gene cluster 3abc; E, envelope protein gene; M, membrane protein gene; N ... Spike Protein Fusion Peptide and Feline Coronavirus Virulence Hui-Wen Chang, Herman F. Egberink, Rebecca Halpin, David J. Spiro ... Spike Protein Fusion Peptide and Feline Coronavirus Virulence. ...
  • The fusion of neurotransmitter filled vesicles with the presynaptic membrane is the key step in the neuronal signaling cascade and is mediated by soluble N-ethylmaleimide-sensitive factor attachment receptor proteins (SNAREs). (
  • The interaction of the three SNARE proteins synaptobrevin 2 (syb 2), syntaxin 1A, and SNAP25 (synaptosomal associated protein of 25 kDa) is pivotal to overcome the energy barrier that leads to merging of the opposing lipid bilayers and results in the transfer of neurotransmitters across the presynaptic membrane and into the synaptic cleft. (
  • Membrane fusion proteins (not to be confused with chimeric or fusion proteins ) are proteins that cause fusion of biological membranes . (
  • Fusion proteins can originate from genes encoded by infectious enveloped viruses , ancient retroviruses integrated into the host genome, [1] or solely by the host genome. (
  • [2] Post-transcriptional modifications made to the fusion proteins by the host, namely addition and modification of glycans and acetyl groups , can drastically affect fusogenicity (the ability to fuse). (
  • Vesicle fusion events involved in neurotransmitter trafficking also relies on the catalytic activity of fusion proteins. (
  • The SNARE family include bona fide eukaryotic fusion proteins. (
  • They are domesticated viral class I fusion proteins. (
  • Enveloped viruses readily overcome the thermodynamic barrier of merging two plasma membranes by storing kinetic energy in fusion (F) proteins. (
  • 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. (
  • Some F components solely drive fusion while a subset of F proteins can interact with host factors . (
  • There are four groups of fusion proteins categorized by their structure and mechanism of fusion. (
  • Class I fusion proteins resemble influenzavirus hemagglutinin in their structure. (
  • Class III fusion proteins are distinct from I and II. (
  • Class IV fusion proteins, better known as fusion-associated small transmembrane proteins (FAST), are the smallest type of fusion protein. (
  • They are the only known membrane fusion proteins found in non-enveloped viruses. (
  • Here we provide a novel mechanism underlying cell-autonomous immunity, which involves the fusion of membranes of a large central vacuole with the plasma membrane, resulting in the discharge of vacuolar antibacterial proteins to the outside of the cells, where bacteria proliferate. (
  • SNARE proteins are the core of the cell's fusion machinery and mediate virtually all known intracellular membrane fusion reactions on which exocytosis and trafficking depend. (
  • 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 (α-, β-, and γ-SNAPs). (
  • Phylogeny as a Guide to Structure and Function of Membrane Transport Proteins. (
  • Viral membrane fusion proceeds through a series of steps that are driven by triggered conformational adjustments of viral envelope glycoproteins so-called fusion proteins. (
  • This entry step is controlled by specific proteins at the viral surface that are primed to undergo dramatic structural changes and thus travel membrane fusion. (
  • Intro Membrane fusion procedures are firmly regulated-spatially and temporally-by particular control proteins in both viral and mobile fusion systems [1-4]. (
  • Many enveloped infections use only an individual proteins to mediate the fusion of their membrane having a mobile membrane during pathogen admittance [3 4 making them an especially interesting program for understanding the membrane fusion procedure in mechanistic conditions. (
  • Throughout these conformational adjustments the fusion proteins expose a section from the polypeptide string ("fusion peptide" [FP]) that inserts in to the mobile membrane to start the fusion procedure [4]. (
  • The protein encoded by this gene is a coiled-coil-forming protein that associates with the SNARE (soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor) complex of proteins and the BLOC-1 (biogenesis of lysosome-related organelles) complex. (
  • The mutagenic analysis of the putative HSV gB fusion loops supports the concept that gB functions as a fusion protein and that its two fusion loops act in much the same way as do the fusion loops of VSV G or the class II fusion proteins. (
  • The subcellular distribution of the proteins Rab5a and syntaxin-4 suggested a role in docking of granules and/or endosomes to the target membrane in the neutrophil. (
  • The syntaxin-binding protein 1 regulates the formation of a group (complex) of proteins that allows vesicle fusion. (
  • Arf proteins: the membrane traffic police? (
  • sensitivity to membrane phospholipids--each of these activities has been attributed to Arf proteins. (
  • Those tubercular studs colorized maroon, are known as H-proteins (hemagglutinin), while those colorized gray, represented what are referred to as F-proteins (fusion). (
  • Annexin VI belongs to a family of calcium-dependent membrane and phospholipid binding proteins. (
  • The various proteins and asymmetric lipid bilayers present in cell membranes form curvatures, resulting in structural transformations to generate vesicles. (
  • The envelope of virus is inlaid with two virally encoded proteins: envelope (E) protein and membrane (M) protein. (
  • In the fusion process, proteins on the vesicles and target membranes bind to each other like the two sides of a zipper. (
  • The biochemical processes commonly inhibited include cell wall synthesis in bacteria and fungi, cell membrane synthesis, synthesis of 30S and 50S ribosomal subunits, nucleic acid metabolism, function of topoisomerases, viral proteases, viral integrases, viral envelope entry/fusion proteins, folate synthesis in parasites, and parasitic chemical detoxification processes. (
  • Here, we show that synthetic amphiphile membranes also undergo fusion, mediated by the protein machinery for synaptic secretion. (
  • Huntingtin is a large membrane-associated scaffolding protein that associates with endocytic and exocytic vesicles and modulates their trafficking along cytoskeletal tracks. (
  • The E2 subunit is initially synthesized as a precursor protein p62, which is proteolytically processed to the mature E2 form before virus budding at the plasma membrane. (
  • The p62 (E2) protein mediates binding of the heterodimer to the nucleocapsid during virus budding, whereas E1 carries the entry functions of the virus, that is, cell binding and low pH-mediated membrane fusion activity. (
  • HAP2 is a domesticated viral class II fusion protein found in diverse eukaryotes including Toxoplasma , vascular plants , and fruit flies. (
  • This protein is essential for gamete fusion in these organisms. (
  • The N-ethylmaleimide sensitive fusion protein (NSF) is required for fusion of lipid bilayers at many locations within eukaryotic cells. (
  • These ATPase are found as coomponents of several protein secretion systems as well as synaptosomal fusion systems. (
  • Using biochemical and cellular approaches we demonstrate that the chlamydial protein IncA directly and specifically inhibits late endocytic SNARE-mediated membrane fusion. (
  • Specific structural classes of viral fusion protein have been determined showing radically different architectures and agencies for the virion [4-6]. (
  • To verify that the hemifusion assay was capable of detecting hemifusions, glycosylphosphatidylinositol (GPI)-linked hemagglutinin (HA) was used, a variant of the influenza virus fusion protein, HA, known to stall the fusion process before productive fusion pores are formed. (
  • This is particularly true for membrane protein expression (Wagner et al. (
  • 2008). Membrane protein expression and protein export in E. coli are both limited by the throughput capacity of the Sec translocase and in some cases the Tat translocase. (
  • Lemo System™ enables simple, rapid optimization of membrane protein expression. (
  • A shortage of this protein impairs the formation of the protein complex that allows vesicle fusion and the release of neurotransmitters from neurons. (
  • However, PLD1 precipitated from cell lysates with immobilized glutathione S-transferase-RalA fusion protein is active. (
  • The F-protein is responsible for fusion of the virus and host cell membranes, viral penetration, and hemolysis. (
  • CD137 is a type I membrane protein and a member of the tumor necrosis factor receptor superfamily (1,2). (
  • The MS4A1 gene (MS4A1-stands for 'Membrane Spanning 4-Domains A1' ), is a protein coding gene located on ch. (
  • 2018). The VPS33B gene is involved in intracellular protein transport and membrane fusion. (
  • S2 contains basic elements needed for the membrane fusion.The S protein plays key parts in the induction of neutralizing-antibody and T-cell responses, as well as protective immunity. (
  • 2015). This endosomal luminal low pH is vital for intracellular membrane site visitors, cytosolic pH upkeep, protein degradation and receptor-mediated endocytosis (Cotter et al. (
  • When studying vesicle transport in mammalian cells in the 1980s and 1990s, Rothman discovered that a protein complex enables vesicles to dock and fuse with their target membranes. (
  • We will discuss fluorescence as a general language used to read out biological phenomena as diverse as protein localization, membrane tension, surface phenomena, and enzyme activity. (
  • We will proceed to discuss protein labeling strategies and fusion protein design. (
  • Protein p48 may play a role in viral replication by interacting with host VAPA, a vesicle-associated membrane protein that plays a role in SNARE-mediated vesicle fusion. (
  • Protein P22 may play a role in targeting replication complex to intracellular membranes. (
  • Us9 is a novel type II membrane protein expressed as a highly phosphorylated protein late in ADV infection. (
  • By fusing the jellyfish enhanced green fluorescent protein reporter molecule (EGFP) to the carboxy-terminus of Us9, we demonstrated that Us9 not only is capable of targeting a Us9-EGFP fusion protein to the Golgi compartment, it also is able to direct efficient incorporation of such chimeric molecules into infectious viral particles. (
  • We integrated fusogenic SNAREs in polymer and hybrid vesicles and observed efficient membrane and content mixing. (
  • Here we use a multidisciplinary approach including subcellular membrane purification, fluorescence spectroscopy and Fö rster resonance energy transfer (FRET)/two-photon fluorescence lifetime imaging microscopy (FLIM) to demonstrate that initiation of vesicle fusion arises from two unique sites where these vesicles bind to chromatin. (
  • They observe fusion events on vesicles predominantly present on the same nanotube. (
  • However, they go on to identify the fusion of vesicles located on different nanotubes in later stages. (
  • To identify the mechanism of fusion they use a mathematical model to reproduce the above-mentioned fusion The initial mechanism of vesicle fusion occurring on vesicles located on the same nanotube is supported by their simulations. (
  • On the other hand, the second mechanism of fusion results in the stabilization of a pore (a gap between the top of the two vesicles and the neck of the two vesicles), which makes it less probable in their simulation. (
  • Therefore, the authors conclude that the fusion process should predominantly start at the interconnected base of vesicles being the nanotube. (
  • Thus they are suitable to monitor the process of content transfer through a fusion pore of added vesicles filled with a water soluble dye by means of fluorescence microscopy. (
  • We hypothesize that this principle finds physiological use to boost fusion rates to meet the demanding timescales of neurotransmission, exploiting the large number of v-SNAREs available in synaptic vesicles. (
  • The intracellular transport of cargo and the subsequent fusion of cargo-loaded vesicles with their target compartments are essential for the function and survival of eukaryotic cells. (
  • Calcium can then enter the cell and initiates the fusion of the neurotransmitter vesicles with the membrane. (
  • Fission and fusion processes between vesicles and cell membranes are reversible in living organisms. (
  • The reduced electrostatic repulsion between ammonium cations and the spontaneously deprotonated neutral amino group induced anisotropic membrane curvature, resulting in membrane fission to form vesicles with a detailed understanding at the molecular level. (
  • Furthermore, the reversible transformation of vesicles to membranes upon changing the pH provides a novel synthetic system exhibiting both fission and fusion processes. (
  • Miniature bubble-like vesicles, surrounded by membranes, shuttle the cargo between organelles or fuse with the outer membrane of the cell and release their cargo to the outside. (
  • The signalling molecules, neurotransmitters, are released from vesicles that fuse with the outer membrane of nerve cells by using the machinery discovered by Rothman and Schekman. (
  • Membrane fusion plays a central role in many cell processes from vesicular transport to nuclear envelope reconstitution at mitosis but the mechanisms that underlie fusion of natural membranes are not well understood. (
  • Molecular Mechanisms of Membrane Transporter. (
  • Analysis of this HA gene shows that it is closely related to avian A(H5) viruses in HA clade and lacked amino acid changes that improve recognition of mammalian receptors or fusion of the viral membrane with the host endosomal membranes. (
  • In the present study, we established a virus-free, stable reporter fusion inhibition assay (SRFIA) specifically designed to identify compounds interfering with virus-induced membrane fusion. (
  • Virus-Induced Membrane Fusion in Neurodegenerative Disorders. (
  • Yet natural membranes are also dynamically remodeled in multiple cellular processes. (
  • However, the specific role of lipids in membrane fusion of natural membranes is not well established. (
  • 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. (
  • This interaction may target replication complex to intracellular membranes (By similarity). (
  • In addition, we found that huntingtin is required for secretory vesicle fusion at the plasma membrane. (
  • Furthermore, the increase in vesicle membrane size or membrane growth to mimic cell growth could occur by vesicle-vesicle fusion initiated by surface functionalization, or due to various sources of external stimuli such as fusogenic peptides, synthetic lipids, polyethylene glycol, ions, an electric field pulse, and light irradiation [3]. (
  • Rizo J, Rosenmund C. Synaptic vesicle fusion. (
  • Annexin VI has been implicated in mediating the endosome aggregation and vesicle fusion in secreting epithelia during exocytosis. (
  • This thesis is concerned with studies on two aspects of membrane fusion. (
  • An disturbance with this technique could be a effective opportinity for inhibiting pathogen replication and fusion inhibitors possess recently turn into a beneficial addition to the armamentarium of anti-HIV remedies. (
  • The performance of the SRFIA was tested for the quantification of SARS-CoV-2- and HSV-1-induced cell-cell fusion, respectively, showing high sensitivity and specificity, as well as the reliable identification of known fusion inhibitors. (
  • The first aspect is the mechanism of membrane fusion in electrically-induced cell fusion. (
  • The conditions that favour hemi-fusion as opposed to complete fusion were characterised, and the possibility that hemi-fusion might precede complete electrically-induced cell fusion are discussed. (
  • The procoagulant activity of human erythrocytes, which provides a measure of the translocation of phosphatidylserine from the inner to the outer monolayer of the plasma membrane, has been compared with the percentage cell fusion in experiments on erythrocyte fusion induced by electrical breakdown pulses under differing experimental conditions. (
  • Viral fusogens merge viral and cell membranes during cell penetration. (
  • They are found in reoviruses , which are non-enveloped viruses and are specialized for cell-cell rather than virus-cell fusion, forming syncytia . (
  • Femtosecond laser pulses were appliedto initiate cell fusion as well as to performreversible permeabilization of cell membranerequired for efficient injection of extrinsicsubstances into the target cells. (
  • Laser-based cellfusion of mammalian embryo blastomeres as wellas fusion of cell bodies of neurons of molluskLymnaea stagnalis were successfully carried out byapplying single femtosecond laser pulses (secondharmonic of a Cr:Forsterite laser system) 620 nm,100 fs with the fluences of 0.42-0.71 J/cm2. (
  • It wasshown that the fusion of cells was completed within5-60 minutes depending on the cell type. (
  • Successfulpermeabilization of a cell membrane andoptoinjection of a membrane impermeable dye wasperformed with the help of a compact laser systemfor cell microsurgery DissCell-F (ytterbium laser,1050 nm, 75 MHz, ~115 fs). (
  • In both cases the laserirradiation parameters were thoroughly optimized toachieve high viability of treated cells and highefficiency of the procedures of cell fusion andoptical injection. (
  • Ultimately, these results illustrate that both pathogenic and non-pathogenic bacteria regulate immune cell function through the manipulation membrane fusion events. (
  • Cell-cell fusion by the transient transfection of viral fusogens in the presence of doxycycline results in the expression of the reporter enzyme secreted alkaline phosphatase (SEAP) and the fluorescent nuclear localization marker EYFPNuc. (
  • In conclusion, the SRFIA reported here is well suited for high-throughput screening for new antiviral agents and essentially will be applicable to all viral fusogens causing cell-cell fusion in Vero cells. (
  • This multipartite system recapitulates the basic steps of virus-cell fusion, i.e. receptor recognition, triggering of fusion and fusion execution. (
  • however, if guanosine 5'-[gamma-thio]triphosphate was added to activate Arf and stimulate translocation to the membrane, high levels of Arf were precipitated by RalA from cell lysates. (
  • the other subunit, S2, fuses with the cell membrane. (
  • After the S1 subunit of the spike binds to the ACE-2 enzyme on the cell membrane surface, TMPRSS2 activates the spike and cleaves ACE-2. (
  • TMPRSS2 also acts on the S2 subunit of the spike glycoprotein, causing an irreversible conformational change, activating it, and facilitating fusion of the virus to the cell membrane. (
  • Damage was determined by ciliary disarray, ciliary fusion, missing cilia, ruptured sensory cell membrane, and missing hair cells. (
  • attaches the virion to the cell membrane by interacting with host receptor, initiating the infection (By similarity). (
  • Some S oligomers are transported to the host plasma membrane, where they may mediate cell-cell fusion. (
  • Additionally, a second cleavage leads to the release of a fusion peptide after viral attachment to host cell receptor (By similarity). (
  • 1980). As a way to enter the cell each enveloped and non-enveloped viruses want to connect to the host cell receptors and both fuse with the plasma or endosomal membrane (enveloped viruses) or disrupt/type pore(s) within the plasma membrane (non-enveloped viruses) to achieve entry into the cell (Cossart and Helenius, 2014). (
  • The E glycoprotein is the major component of the virion surface and is responsible for the receptor-mediated endocytic fusion and subsequent cell entry, as well as direct viral assembly & budding, and immunogenicity. (
  • The same principle operates inside the cell and when a vesicle binds to the cell´s outer membrane to release its contents. (
  • Research in structural virology aims to provide a molecular description of the dynamics of viral structures at various essential stages of the infectious cycle: assembly of the viral particle, fusion of viral and cell membranes, packaging and ejection of the viral genome. (
  • GPRC5D has seven putative transmembrane segments and is expressed in the cell membrane. (
  • Other factors associated with the appearance of oral cancer include the action of alcohol in facilitating the passage of carcinogens via the cell membrane of the oral mucosa and the effect of alcohol on the heightened metabolic activity of the liver which could thereby activate carcinogenic substances 15-16 . (
  • The peptide regions required to drive fusion are formed from the turns between the β-sheets. (
  • Proteolysis by cathepsin CTSL may unmask the fusion peptide of S2 and activate membranes fusion within endosomes. (
  • Structural membrane biochemistry and method. (
  • We also captured the virus - virus fusion events, which provided pieces of structural evidence for Delta 's attenuated dependency on cellular factors for fusion activation, and proposed a model of S-mediated membrane fusion . (
  • Such membranes will also be part of a particular structural course of viruses-so-called enveloped viruses-that consist of influenza disease HIV severe severe respiratory symptoms coronavirus Ebola disease yellow fever disease and many more. (
  • SARS-CoV-1 and SARS-CoV-2, which share about 80% structural identity, do this by harnessing the action of the angiotensin converting enzyme, ACE-2, which is expressed in the membranes of many cells in the body, including lung alveolar epithelial cells. (
  • PSMs are continuous lipid bilayers with solid supported parts (s-PSM) as well as freestanding membranes spanning large aqueous compartments (f-PSM). (
  • The membrane-proximal (MPR), transmembrane (TMD), and cytoplasmic (CTD) domains form a uniquely folded trimeric pedestal beneath the ectodomain, which balances dynamic flexibility with extensive, stabilizing membrane interactions. (
  • The fusion splicer market was valued at USD 570.5 Million in 2016 and is expected to reach USD 762.3 Million by 2022, at a CAGR of 4.72% during the forecast period. (
  • Moreover, the fusion splicer market registered a shipment of 65,735 units in 2016 and is expected to reach 97,353 units by 2022, at a CAGR of 6.52% during the forecast period. (
  • Heat-Resistant Factors In Human Erythrocyte Membranes Mediate Cd4-Dependent Fusion With Cells Expressing Hiv-1 Envelope Glycoproteins. (
  • The multipartite entry‐fusion system of herpes simplex virus is made of a quartet of glycoproteins-gD, gB, gH·gL-and three alternative gD receptors, herpesvirus entry mediator (HVEM), nectin1 and modified sites on heparan sulphate. (
  • The hemagglutinin (HA) gene codes for one of the two surface glycoproteins and is central to species specificity because it is responsible for virus attachment and fusion with host cells. (
  • We determined bending rigidity and pore edge tension as key parameters for fusion and described its plausible progression through cryo-EM snapshots. (
  • To investigate this fundamental process, pore-spanning membranes (PSMs) were utilized in this work as a model system of the presynaptic membrane. (
  • The complex mitochondrial network is the result of the two ongoing forces of fusion and fission of inner and outer membranes. (
  • It is proposed that placing the gH/gL activation under the integrin trigger point enables HSV to synchronize virion endocytosis with the cascade of glycoprotein activation that culminates in execution of fusion. (
  • A proprietary waterproof, breathable membrane that lets vapor out without letting water in. (
  • The gloves include a waterpoof breathable membrane, over 150 grams of insulation and a soft tricot fleece lining. (
  • Die Fusion von Neurotransmitter gefüllten Vesikeln mit der präsynaptischen Membran ist der Schlüsselschritt in der neuronalen Signaltransduktion und wird durch SNARE- (soluble N-ethylmaleimide-sensitive factor attachment receptor) Proteine vermittelt. (
  • The Greek download recruits a microcytic morphogenesis of the the characteristic membrane energy evidence( IL2RG, CD132, or Gc) and the IL7-receptor alcoholism diabetes( IL7R, IL7RA, developmental). (
  • This cilia in the life of the serine by receptor fusion kinases of the Src neddylation( 1). (
  • Membrane Trafficking, Fusion, and Synaptic. (
  • To release its neurotransmitters, a synaptic vesicle must join (fuse) with the outer membrane of the neuron. (
  • Divalent cations in the pulsing medium may interact with phosphatidylserine molecules, translocated from the inner to the outer monolayer of the erythrocyte plasma membrane by breakdown pulses, to stabilise the pulsed erythrocyte membrane against haemolysis, and to assist the formation of pearl chains of pulsed cells. (
  • It was found that the entry of sugar molecules, via electropores in the plasma membrane, facilitated the rounding-up of electrically fused erythrocytes into giant cells, while impermeable molecules e.g. poly (ethylene glycol) or dextran inhibited this process. (
  • The formation of a syncytium, a mass of cytoplasm containing several nuclei enclosed within a single plasma membrane, by the fusion of the plasma membranes of two or more individual cells. (
  • The membrane component is essential, since bilayer membranes that surround all types of cells as we know them today are thought to have originated from spontaneous self- assembly of amphiphilic molecules. (
  • Noninfectivity resulted from impaired uptake into cells, as well as from the inability of the virus to promote membrane fusion in the mildly acidic conditions of the endosome. (
  • 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 . (
  • We report on results of using femtosecond laserscalpel for microsurgery of plasma membrane ofliving cells. (
  • The fusion of the viral with a Ticagrelor cellular membrane is a key step in Ticagrelor the life cycle of these viruses and allows the delivery of their genetic information into cells. (
  • Many of the MCG were observed in the process of fusion with plasma membranes of granular cells adjacent to the stratum corneum. (
  • These studies suggest that cholesterol can alter the conformation of IFITMs in membrane bilayers and directly interact with S -palmitoylated IFITMs in cells. (
  • SV40 virus was rescued from revertant cells by fusion with permissive monkey cells. (
  • The data presented suggest that the property of contact inhibition in revertant cells is related to the sialic acid content of the plasma membrane and that changes in sialic acid content of transformed cells are not directly specified by the viral genome. (
  • In the ultra-structure of the treated group, an increase in inter-cellular space, fusion of the secretory granules and the presence of cells in a degenerative state were observed. (
  • Once in an unfettered cluster, we estimate ≥15 SNAREpins are required for fusion within the ∼1-ms timescale of neurotransmitter release. (
  • As part of the SNARE complex, it is required for vesicle docking and fusion and regulates neurotransmitter release. (
  • ADOA plus is caused by mutations in the OPA1 gene (3q29), encoding a dynamin-like GTPase involved in the fusion of the inner mitochondrial membrane. (
  • Thus, this novel defense strategy through proteasome-regulating membrane fusion of the vacuolar and plasma membranes provides plants with a mechanism for attacking intercellular bacterial pathogens. (
  • Deletion analysis of the cytoplasmic tail reveals that an acidic cluster containing putative phosphorylation sites is necessary for the recycling of Us9 from the plasma membrane. (
  • The absence of this cluster results in the relocalization of Us9 to the plasma membrane due to a defect in endocytosis. (
  • Site-directed mutagenesis of the dileucine motif results in an increase in Us9 plasma membrane staining and a partial internalisation defect. (
  • However, mutants lacking the Us9 dileucine motif required for efficient endocytosis from the plasma membrane have wild type spread and virulence in the rat eye infection model. (
  • We suggest how cycles of complex assembly and disassembly could help confer specificity to the generalized NSF-dependent fusion apparatus. (
  • This patient was a 61-year-old man, the with the relatively weak tissue in mucous brother of the patient in Case 1, who had a membranes [2-4]. (
  • Most commonly, telangiectases involve sodes of severe anaemia in the past and had the mucous membranes, the skin, the con- to have blood transfusions due to a decrease junctiva, the retina and the gastrointestinal in serum haemoglobin level to 9 g/dL. (
  • Activation of phospholipase D1 (PLD1) by Arf has been implicated in vesicle transport and membrane trafficking. (
  • Pathogenic bacteria, such as Chlamydia trachomatis, inhibit membrane fusion events with the phagocytic pathway to circumvent the anti-bacterial immune response, thus impairing the ability of the immune system to clear the pathogen. (
  • The second aspect is the mechanism of membrane fusion induced by fusogenic viral peptides. (
  • We discuss the general implications of membrane fusion regulation and spatial control utilising such a mechanism. (
  • Moreover, pieces of molecular evidence for the detailed mechanism of S-mediated membrane fusion are missing. (
  • Studies with synthetic membranes and theoretical considerations indicate that accumulation of lipids characterised by negative curvature such as diacylglycerol (DAG) facilitate fusion. (
  • Fusion conformation change can often be controlled by pH. (
  • 2018). The low pH for fusion varies between viruses making some viruses to fuse both throughout early endosomes (comparatively excessive pH ∼ 6.0) or late endosomes (low pH ∼ 5) to launch its content material to the cytosol (White and Whittaker, 2016). (
  • The SNAREpins self-organized into a circular cluster at the fusion site, driven by entropic forces that originate in steric-electrostatic interactions among SNAREpins and membranes. (
  • Herein, we report a supramolecular membrane system through donor-acceptor interactions using a π-deficient acceptor and π-rich donor as building blocks. (
  • These findings demonstrate that dynamic membrane phenomena can be reconstituted in synthetic materials, thereby providing new tools for the assembly of synthetic protocells. (
  • Evidence was found from both fluorescence microscopy and freeze-fracture electron microscopy for the occurrence of hemi-fusion in the electrofusion of human erythrocytes. (
  • Ross B, Loew LM, Baker B . Decision letter: Optical estimation of absolute membrane potential using fluorescence lifetime imaging Elife . (
  • Membrane Fusion" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus, MeSH (Medical Subject Headings) . (
  • The fluoride ion selective membrane utilizes a membrane consisting of a slice of a single crystal of lanthanum fluoride that has been doped with europium (II) fluoride to improve its conductivity (Skoog et al. (
  • Fusion is subsequently propagated to the endoplasmic reticulum-derived membranes that make up the bulk of the NE to ultimately enclose the chromatin. (
  • Membrane fusion is critical for many biological processes, especially in eukaryotic development and viral entry . (
  • State Key Laboratory of Membrane Biology & Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China. (
  • In June 2016, the company introduced the FITEL S179 hand-held, core alignment fusion splicer, which offers powerful performance and delivers fast and reliable optical fiber splicing even under harsh environmental conditions. (
  • Large numbers of membrane coaling granules (MCG) emerged in the 1 h specimens. (
  • Simultaneous imaging of lipid dye diffusion from the PSM into the vesicular membrane via a fusion stalk was used to quantify different fusion pathways. (
  • Fusion pathways are also involved in the development of musculoskeletal and nervous system tissues. (
  • Several members of the annexin family have been implicated in membrane-related events along exocytotic and endocytotic pathways. (
  • The view that the sorting of gB to MVB membranes may represent a critical step in HSV envelopment and egress and that modified MVBs membranes constitute a platform for HSV cytoplasmic envelopment or that MVB components are recruited to the site(s) of envelopment is supported. (
  • We investigated fusion between phagosomes containing the intracellular pathogen Mycobacterium tuberculosis versus the extracellular pathogen Staphylococcus aureus (designated MCP for mycobacteria-containing phagosome and SCP for S. aureus -containing phagosome) and cytoplasmic compartments in human neutrophils. (
  • This work offers generated additional insights in to the system of flavivirus membrane fusion and may thus provide fresh leads for the introduction of antiviral real estate agents against these essential human pathogens. (
  • Membrane fusion constitutes an essential step in the replication cycle of numerous viral pathogens, hence it represents an important druggable target. (
  • The relationships between the observed secondary structures and orientation of these fusion peptides and how they may induce membrane fusion are discussed. (
  • The binding domain is rich in α-helices and hydrophobic fusion peptides located near the N-terminus. (
  • Fusion is catalyzed when vesicle-associated v-SNAREs form trans -SNARE complexes ("SNAREpins") with target membrane-associated t-SNAREs, a zippering-like process releasing ∼65 kT per SNAREpin. (
  • To capture the collective behavior on the long timescales of fusion, we developed a highly coarse-grained model that retains key biophysical SNARE properties such as the zippering energy landscape and the surface charge distribution. (