Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.
The main structural coat protein of COATED VESICLES which play a key role in the intracellular transport between membranous organelles. Each molecule of clathrin consists of three light chains (CLATHRIN LIGHT CHAINS) and three heavy chains (CLATHRIN HEAVY CHAINS) that form a structure called a triskelion. Clathrin also interacts with cytoskeletal proteins.
A family of high molecular weight GTP phosphohydrolases that play a direct role in vesicle transport. They associate with microtubule bundles (MICROTUBULES) and are believed to produce mechanical force via a process linked to GTP hydrolysis. This enzyme was formerly listed as EC
Vesicles formed when cell-membrane coated pits (COATED PITS, CELL-MEMBRANE) invaginate and pinch off. The outer surface of these vesicles is covered with a lattice-like network of the protein CLATHRIN. Shortly after formation, however, the clathrin coat is removed and the vesicles are referred to as ENDOSOMES.
Cytoplasmic vesicles formed when COATED VESICLES shed their CLATHRIN coat. Endosomes internalize macromolecules bound by receptors on the cell surface.
Specialized regions of the cell membrane composed of pits coated with a bristle covering made of the protein CLATHRIN. These pits are the entry route for macromolecules bound by cell surface receptors. The pits are then internalized into the cytoplasm to form the COATED VESICLES.
A subtype of dynamin found primarily in the NEURONS of the brain.
An adaptor protein complex primarily involved in the formation of clathrin-related endocytotic vesicles (ENDOSOMES) at the CELL MEMBRANE.
A subtype of dynamin found ubiquitously expressed in a variety of tissues.
An iron-binding beta1-globulin that is synthesized in the LIVER and secreted into the blood. It plays a central role in the transport of IRON throughout the circulation. A variety of transferrin isoforms exist in humans, including some that are considered markers for specific disease states.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
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
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.
Endocytic/exocytic CELL MEMBRANE STRUCTURES rich in glycosphingolipids, cholesterol, and lipid-anchored membrane proteins that function in ENDOCYTOSIS (potocytosis), transcytosis, and SIGNAL TRANSDUCTION. Caveolae assume various shapes from open pits to closed vesicles. Caveolar coats are composed of CAVEOLINS.
The heavy chain subunits of clathrin.
The engulfing of liquids by cells by a process of invagination and closure of the cell membrane to form fluid-filled vacuoles.
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)
An LDL-RECEPTOR RELATED PROTEIN found in the neuroepithelium and in proximal tubular cells of the kidney. It is considered a multiligand receptor in that it binds to a variety of ligands with relatively high affinity and may function in mediating the uptake and lysosomal degradation of macromolecules such as: LIPOPROTEINS; ENDOPEPTIDASES; and PROTEASE INHIBITORS.
A class of proteins involved in the transport of molecules via TRANSPORT VESICLES. They perform functions such as binding to the cell membrane, capturing cargo molecules and promoting the assembly of CLATHRIN. The majority of adaptor proteins exist as multi-subunit complexes, however monomeric varieties have also been found.
Established cell cultures that have the potential to propagate indefinitely.
Membrane glycoproteins found in high concentrations on iron-utilizing cells. They specifically bind iron-bearing transferrin, are endocytosed with its ligand and then returned to the cell surface where transferrin without its iron is released.
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.
A family of large adaptin protein subunits of approximately 100 kDa in size. They have been primarily found as components of ADAPTOR PROTEIN COMPLEX 2.
Cellular release of material within membrane-limited vesicles by fusion of the vesicles with the CELL MEMBRANE.
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.
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.
Regulatory proteins that down-regulate phosphorylated G-protein membrane receptors, including rod and cone photoreceptors and adrenergic receptors.
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.
Enzymes that hydrolyze GTP to GDP. EC 3.6.1.-.
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 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.
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.
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 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.
The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.
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.
An enzyme isolated from horseradish which is able to act as an antigen. It is frequently used as a histochemical tracer for light and electron microscopy. Its antigenicity has permitted its use as a combined antigen and marker in experimental immunology.
The prototypical phenothiazine antipsychotic drug. Like the other drugs in this class chlorpromazine's antipsychotic actions are thought to be due to long-term adaptation by the brain to blocking DOPAMINE RECEPTORS. Chlorpromazine has several other actions and therapeutic uses, including as an antiemetic and in the treatment of intractable hiccup.
A tyrosine phosphoprotein that plays an essential role in CAVEOLAE formation. It binds CHOLESTEROL and is involved in LIPIDS transport, membrane traffic, and SIGNAL TRANSDUCTION.
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.
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.
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.
Compounds of the general formula R:N.NR2, as resulting from the action of hydrazines with aldehydes or ketones. (Grant & Hackh's Chemical Dictionary, 5th ed)
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.
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.
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.
A complex of polyene antibiotics obtained from Streptomyces filipinensis. Filipin III alters membrane function by interfering with membrane sterols, inhibits mitochondrial respiration, and is proposed as an antifungal agent. Filipins I, II, and IV are less important.
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.
A family of medium adaptin protein subunits of approximately 45 KDa in size. They have been primarily found as components of ADAPTOR PROTEIN COMPLEX 3 and ADAPTOR PROTEIN COMPLEX 4.
Derivatives of ammonium compounds, NH4+ Y-, in which all four of the hydrogens bonded to nitrogen have been replaced with hydrocarbyl groups. These are distinguished from IMINES which are RN=CR2.
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.
A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.
The rate dynamics in chemical or physical systems.
Detergent-insoluble CELL MEMBRANE components. They are enriched in SPHINGOLIPIDS and CHOLESTEROL and clustered with glycosyl-phosphatidylinositol (GPI)-anchored proteins.
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 C-type lectin that is a cell surface receptor for ASIALOGLYCOPROTEINS. It is found primarily in the LIVER where it mediates the endocytosis of serum glycoproteins.
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.
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.
Endogenous glycoproteins from which SIALIC ACID has been removed by the action of sialidases. They bind tightly to the ASIALOGLYCOPROTEIN RECEPTOR which is located on hepatocyte plasma membranes. After internalization by adsorptive ENDOCYTOSIS they are delivered to LYSOSOMES for degradation. Therefore receptor-mediated clearance of asialoglycoproteins is an important aspect of the turnover of plasma glycoproteins. They are elevated in serum of patients with HEPATIC CIRRHOSIS or HEPATITIS.
A large family of MONOMERIC GTP-BINDING PROTEINS that play a key role in cellular secretory and endocytic pathways. EC 3.6.1.-.
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).)
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.
Any spaces or cavities within a cell. They may function in digestion, storage, secretion, or excretion.
A family of proteins that play a role as cofactors in the process of CLATHRIN recycling in cells.
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.
Transport proteins that carry specific substances in the blood or across cell membranes.
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.
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.
The light chain subunits of clathrin.
A subclass of clathrin assembly proteins that occur as monomers.
Orientation of intracellular structures especially with respect to the apical and basolateral domains of the plasma membrane. Polarized cells must direct proteins from the Golgi apparatus to the appropriate domain since tight junctions prevent proteins from diffusing between the two domains.
A family of pheromone receptors that were initially discovered in SACCHAROMYCES CEREVISIAE as proteins necessary for fungal conjugation. Each mating factor receptor is expressed in HAPLOID CELLS of a single mating type.
A set of protein subcomplexes involved in PROTEIN SORTING of UBIQUITINATED PROTEINS into intraluminal vesicles of MULTIVESICULAR BODIES and in membrane scission during formation of intraluminal vesicles, during the final step of CYTOKINESIS, and during the budding of enveloped viruses. The ESCRT machinery is comprised of the protein products of Class E vacuolar protein sorting genes.
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 partitioning within cells due to the selectively permeable membranes which enclose each of the separate parts, e.g., mitochondria, lysosomes, etc.
A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g., an antigen binding to an antibody, a hormone or neurotransmitter binding to a receptor, or a substrate or allosteric effector binding to an enzyme. Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex. (From Dorland, 27th ed)
The main structural proteins of CAVEOLAE. Several distinct genes for caveolins have been identified.
A subtype of dynamin found expressed exclusively in the testis, lung and brain.
Incorporation of biotinyl groups into molecules.
A foul-smelling diamine formed by bacterial decarboxylation of lysine.
A family of large adaptin protein complex subunits of approximately 90-130 kDa in size.
The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.
Reduced (protonated) form of THIAZOLES. They can be oxidized to THIAZOLIDINEDIONES.
A genetically related subfamily of RAB GTP-BINDING PROTEINS involved in recycling of proteins such as cell surface receptors from early endosomes to the cell surface. This enzyme was formerly listed as EC
New World marsupials of the family Didelphidae. Opossums are omnivorous, largely nocturnal and arboreal MAMMALS, grow to about three feet in length, including the scaly prehensile tail, and have an abdominal pouch in which the young are carried at birth.
The ability of a substrate to retain an electrical charge.
The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.
A large family of phosphatidylinositol phosphate-binding proteins that are involved in mediating intracellular transport and sorting of proteins via a variety of endocytic pathways.
An acidifying agent that has expectorant and diuretic effects. Also used in etching and batteries and as a flux in electroplating.
A broad category of carrier proteins that play a role in SIGNAL TRANSDUCTION. They generally contain several modular domains, each of which having its own binding activity, and act by forming complexes with other intracellular-signaling molecules. Signal-transducing adaptor proteins lack enzyme activity, however their activity can be modulated by other signal-transducing enzymes
An antiprotozoal agent produced by Streptomyces cinnamonensis. It exerts its effect during the development of first-generation trophozoites into first-generation schizonts within the intestinal epithelial cells. It does not interfere with hosts' development of acquired immunity to the majority of coccidial species. Monensin is a sodium and proton selective ionophore and is widely used as such in biochemical studies.
A cell line generated from human embryonic kidney cells that were transformed with human adenovirus type 5.
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 complex of seven proteins including ARP2 PROTEIN and ARP3 PROTEIN that plays an essential role in maintenance and assembly of the CYTOSKELETON. Arp2-3 complex binds WASP PROTEIN and existing ACTIN FILAMENTS, and it nucleates the formation of new branch point filaments.
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)
MONOMERIC GTP-BINDING PROTEINS that were initially recognized as allosteric activators of the MONO(ADP-RIBOSE) TRANSFERASE of the CHOLERA TOXIN catalytic subunit. They are involved in vesicle trafficking and activation of PHOSPHOLIPASE D. This enzyme was formerly listed as EC
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.
Monomeric subunits of primarily globular ACTIN and found in the cytoplasmic matrix of almost all cells. They are often associated with microtubules and may play a role in cytoskeletal function and/or mediate movement of the cell or the organelles within the cell.
The prototypical antimalarial agent with a mechanism that is not well understood. It has also been used to treat rheumatoid arthritis, systemic lupus erythematosus, and in the systemic therapy of amebic liver abscesses.
The act of ligating UBIQUITINS to PROTEINS to form ubiquitin-protein ligase complexes to label proteins for transport to the PROTEASOME ENDOPEPTIDASE COMPLEX where proteolysis occurs.
Elements of limited time intervals, contributing to particular results or situations.
Fluorescent probe capable of being conjugated to tissue and proteins. It is used as a label in fluorescent antibody staining procedures as well as protein- and amino acid-binding techniques.
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 distal terminations of axons which are specialized for the release of neurotransmitters. Also included are varicosities along the course of axons which have similar specializations and also release transmitters. Presynaptic terminals in both the central and peripheral nervous systems are included.
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.
A cytochrome oxidase inhibitor which is a nitridizing agent and an inhibitor of terminal oxidation. (From Merck Index, 12th ed)
Small double-stranded, non-protein coding RNAs (21-31 nucleotides) involved in GENE SILENCING functions, especially RNA INTERFERENCE (RNAi). Endogenously, siRNAs are generated from dsRNAs (RNA, DOUBLE-STRANDED) by the same ribonuclease, Dicer, that generates miRNAs (MICRORNAS). The perfect match of the siRNAs' antisense strand to their target RNAs mediates RNAi by siRNA-guided RNA cleavage. siRNAs fall into different classes including trans-acting siRNA (tasiRNA), repeat-associated RNA (rasiRNA), small-scan RNA (scnRNA), and Piwi protein-interacting RNA (piRNA) and have different specific gene silencing functions.
A protein phytotoxin from the seeds of Ricinus communis, the castor oil plant. It agglutinates cells, is proteolytic, and causes lethal inflammation and hemorrhage if taken internally.
A LDL-receptor related protein involved in clearance of chylomicron remnants and of activated ALPHA-MACROGLOBULINS from plasma.
Cyclic GLUCANS consisting of seven (7) glucopyranose units linked by 1,4-glycosidic bonds.
A highly conserved 76-amino acid peptide universally found in eukaryotic cells that functions as a marker for intracellular PROTEIN TRANSPORT and degradation. Ubiquitin becomes activated through a series of complicated steps and forms an isopeptide bond to lysine residues of specific proteins within the cell. These "ubiquitinated" proteins can be recognized and degraded by proteosomes or be transported to specific compartments within the cell.
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 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.
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.
A negative regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.
Proto-oncogene proteins that negatively regulate RECEPTOR PROTEIN-TYROSINE KINASE signaling. It is a UBIQUITIN-PROTEIN LIGASE and the cellular homologue of ONCOGENE PROTEIN V-CBL.
The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.
Receptors on the plasma membrane of nonhepatic cells that specifically bind LDL. The receptors are localized in specialized regions called coated pits. Hypercholesteremia is caused by an allelic genetic defect of three types: 1, receptors do not bind to LDL; 2, there is reduced binding of LDL; and 3, there is normal binding but no internalization of LDL. In consequence, entry of cholesterol esters into the cell is impaired and the intracellular feedback by cholesterol on 3-hydroxy-3-methylglutaryl CoA reductase is lacking.
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.
A fungal metabolite that blocks cytoplasmic cleavage by blocking formation of contractile microfilament structures resulting in multinucleated cell formation, reversible inhibition of cell movement, and the induction of cellular extrusion. Additional reported effects include the inhibition of actin polymerization, DNA synthesis, sperm motility, glucose transport, thyroid secretion, and growth hormone release.
Electron microscopy in which the ELECTRONS or their reaction products that pass down through the specimen are imaged below the plane of the specimen.
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.
A gene silencing phenomenon whereby specific dsRNAs (RNA, DOUBLE-STRANDED) trigger the degradation of homologous mRNA (RNA, MESSENGER). The specific dsRNAs are processed into SMALL INTERFERING RNA (siRNA) which serves as a guide for cleavage of the homologous mRNA in the RNA-INDUCED SILENCING COMPLEX. DNA METHYLATION may also be triggered during this process.
The renal tubule portion that extends from the BOWMAN CAPSULE in the KIDNEY CORTEX into the KIDNEY MEDULLA. The proximal tubule consists of a convoluted proximal segment in the cortex, and a distal straight segment descending into the medulla where it forms the U-shaped LOOP OF HENLE.
A cell surface receptor involved in regulation of cell growth and differentiation. It is specific for EPIDERMAL GROWTH FACTOR and EGF-related peptides including TRANSFORMING GROWTH FACTOR ALPHA; AMPHIREGULIN; and HEPARIN-BINDING EGF-LIKE GROWTH FACTOR. The binding of ligand to the receptor causes activation of its intrinsic tyrosine kinase activity and rapid internalization of the receptor-ligand complex into the cell.
Proteins that originate from insect species belonging to the genus DROSOPHILA. The proteins from the most intensely studied species of Drosophila, DROSOPHILA MELANOGASTER, are the subject of much interest in the area of MORPHOGENESIS and development.
A clathrin adaptor protein complex primarily involved in clathrin-related transport at the TRANS-GOLGI NETWORK.
Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.
Regions of AMINO ACID SEQUENCE similarity in the SRC-FAMILY TYROSINE KINASES that fold into specific functional tertiary structures. The SH1 domain is a CATALYTIC DOMAIN. SH2 and SH3 domains are protein interaction domains. SH2 usually binds PHOSPHOTYROSINE-containing proteins and SH3 interacts with CYTOSKELETAL PROTEINS.
A class of saturated compounds consisting of two rings only, having two or more atoms in common, containing at least one hetero atom, and that take the name of an open chain hydrocarbon containing the same total number of atoms. (From Riguady et al., Nomenclature of Organic Chemistry, 1979, p31)
A group of glucose polymers made by certain bacteria. Dextrans are used therapeutically as plasma volume expanders and anticoagulants. They are also commonly used in biological experimentation and in industry for a wide variety of purposes.
The aggregation of soluble ANTIGENS with ANTIBODIES, alone or with antibody binding factors such as ANTI-ANTIBODIES or STAPHYLOCOCCAL PROTEIN A, into complexes large enough to fall out of solution.
Cell surface receptors that respond to PHEROMONES.
A fungal metabolite which is a macrocyclic lactone exhibiting a wide range of antibiotic activity.
A diverse class of enzymes that interact with UBIQUITIN-CONJUGATING ENZYMES and ubiquitination-specific protein substrates. Each member of this enzyme group has its own distinct specificity for a substrate and ubiquitin-conjugating enzyme. Ubiquitin-protein ligases exist as both monomeric proteins multiprotein complexes.

Endocytosis: EH domains lend a hand. (1/10563)

A number of proteins that have been implicated in endocytosis feature a conserved protein-interaction module known as an EH domain. The three-dimensional structure of an EH domain has recently been solved, and is likely to presage significant advances in understanding molecular mechanisms of endocytosis.  (+info)

Arrestin function in G protein-coupled receptor endocytosis requires phosphoinositide binding. (2/10563)

Internalization of agonist-activated G protein-coupled receptors is mediated by non-visual arrestins, which also bind to clathrin and are therefore thought to act as adaptors in the endocytosis process. Phosphoinositides have been implicated in the regulation of intracellular receptor trafficking, and are known to bind to other coat components including AP-2, AP180 and COPI coatomer. Given these observations, we explored the possibility that phosphoinositides play a role in arrestin's function as an adaptor. High-affinity binding sites for phosphoinositides in beta-arrestin (arrestin2) and arrestin3 (beta-arrestin2) were identified, and dissimilar effects of phosphoinositide and inositol phosphate on arrestin interactions with clathrin and receptor were characterized. Alteration of three basic residues in arrestin3 abolished phosphoinositide binding with complete retention of clathrin and receptor binding. Unlike native protein, upon agonist activation, this mutant arrestin3 expressed in COS1 cells neither supported beta2-adrenergic receptor internalization nor did it concentrate in coated pits, although it was recruited to the plasma membrane. These findings indicate that phosphoinositide binding plays a critical regulatory role in delivery of the receptor-arrestin complex to coated pits, perhaps by providing, with activated receptor, a multi-point attachment of arrestin to the plasma membrane.  (+info)

A cytomegalovirus glycoprotein re-routes MHC class I complexes to lysosomes for degradation. (3/10563)

Mouse cytomegalovirus (MCMV) early gene expression interferes with the major histocompatibility complex class I (MHC class I) pathway of antigen presentation. Here we identify a 48 kDa type I transmembrane glycoprotein encoded by the MCMV early gene m06, which tightly binds to properly folded beta2-microglobulin (beta2m)-associated MHC class I molecules in the endoplasmic reticulum (ER). This association is mediated by the lumenal/transmembrane part of the protein. gp48-MHC class I complexes are transported out of the ER, pass the Golgi, but instead of being expressed on the cell surface, they are redirected to the endocytic route and rapidly degraded in a Lamp-1(+) compartment. As a result, m06-expressing cells are impaired in presenting antigenic peptides to CD8(+) T cells. The cytoplasmic tail of gp48 contains two di-leucine motifs. Mutation of the membrane-proximal di-leucine motif of gp48 restored surface expression of MHC class I, while mutation of the distal one had no effect. The results establish a novel viral mechanism for downregulation of MHC class I molecules by directly binding surface-destined MHC complexes and exploiting the cellular di-leucine sorting machinery for lysosomal degradation.  (+info)

The optically determined size of exo/endo cycling vesicle pool correlates with the quantal content at the neuromuscular junction of Drosophila larvae. (4/10563)

According to the current theory of synaptic transmission, the amplitude of evoked synaptic potentials correlates with the number of synaptic vesicles released at the presynaptic terminals. Synaptic vesicles in presynaptic boutons constitute two distinct pools, namely, exo/endo cycling and reserve pools (). We defined the vesicles that were endocytosed and exocytosed during high K+ stimulation as the exo/endo cycling vesicle pool. To determine the role of exo/endo cycling vesicle pool in synaptic transmission, we estimated the quantal content electrophysiologically, whereas the pool size was determined optically using fluorescent dye FM1-43. We then manipulated the size of the pool with following treatments. First, to change the state of boutons of nerve terminals, motoneuronal axons were severed. With this treatment, the size of exo/endo cycling vesicle pool decreased together with the quantal content. Second, we promoted the FM1-43 uptake using cyclosporin A, which inhibits calcineurin activities and enhances endocytosis. Cyclosporin A increased the total uptake of FM1-43, but neither the size of exo/endo cycling vesicle pool nor the quantal content changed. Third, we increased the size of exo/endo cycling vesicle pool by forskolin, which enhances synaptic transmission. The forskolin treatment increased both the size of exo/endo cycling vesicle pool and the quantal content. Thus, we found that the quantal content was closely correlated with the size of exo/endo cycling vesicle pool but not necessarily with the total uptake of FM1-43 fluorescence by boutons. The results suggest that vesicles in the exo/endo cycling pool primarily participate in evoked exocytosis of vesicles.  (+info)

Identification of low density lipoprotein receptor-related protein-2/megalin as an endocytic receptor for seminal vesicle secretory protein II. (5/10563)

The low density lipoprotein receptor-related protein-2/megalin (LRP-2) is an endocytic receptor that is expressed on the apical surfaces of epithelial cells lining specific regions of the male and female reproductive tracts. In the present study, immunohistochemical staining revealed that LRP-2 is also expressed by epithelial cells lining the ductal region and the ampulla of the rat seminal vesicle. To identify LRP-2 ligands in the seminal vesicle, we probed seminal vesicle fluid with 125I-labeled LRP-2 in a gel-blot overlay assay. A 100-kDa protein (under non-reducing conditions) was found to bind the radiolabeled receptor. The protein was isolated and subjected to protease digestion, and the proteolytic fragments were subjected to mass spectroscopic sequence analysis. As a result, the 100-kDa protein was identified as the seminal vesicle secretory protein II (SVS-II), a major constituent of the seminal coagulum. Using purified preparations of SVS-II and LRP-2, solid-phase binding assays were used to show that the SVS-II bound to the receptor with high affinity (Kd = 5.6 nM). The binding of SVS-II to LRP-2 was inhibited using a known antagonist of LRP-2 function, the 39-kDa receptor-associated protein RAP. Using a series of recombinant subfragments of SVS-II, the LRP-2 binding site was mapped to a stretch of repeated 13-residue modules located in the central portion of the SVS-II polypeptide. To evaluate the ability of LRP-2 to mediate 125I-SVS-II endocytosis and lysosomal degradation, ligand clearance assays were performed using differentiated mouse F9 cells, which express high levels of LRP-2. Radiolabeled SVS-II was internalized and degraded by the cells, and both processes were inhibited by antibodies to LRP-2 or by RAP. The results indicate that LRP-2 binds SVS-II and can mediate its endocytosis leading to lysosomal degradation.  (+info)

5'-Nucleotidase activity of mouse peritoneal macrophages. II. Cellular distribution and effects of endocytosis. (6/10563)

The diazonium salt of sulfanilic acid (DASA) can inactivate about 80% of the total 5'-nucleotidase of viable macrophages. The remaining 20% can be inactivated if the cells are first lysed in detergent, and presumably represents an intracellular pool of 5'-nucleotidase. The bulk of this pool may represent cytoplasmic vesicles derived from plasma membrane by endocytosis. This internal compartment is expanded up to threefold immediately after the cells have ingested a large latex load. This is consistent with previous observations on the internalization of 5'-nucleotidase in latex phagosomes. In latex-filled cells this intracellular pool of enzyme is inactivated over a few hours, and the cells then slowly increase their enzyme activity to nearly normal levels. However, 24 h after latex ingestion the metabolism of 5'-nucleotidase in these recovered cells is abnormal, as the rate of enzyme degradation is about twice the normal rate, and the DASA-insensitive enzyme pool in these cells is strikingly diminished. This may reflect effects of the accumulated indigestible particles on the fate of incoming pinocytic vesicles or on newly synthesized plasma membrane precursor. Another endocytic stimulus, concanavalin A, also reduces the total cell 5'-nucleotidase activity. This effect, which is time and temperature dependent, can be prevented by the competitive sugar alpha-methyl mannose. The concanavalin A inhibition can be reversed in the absence of new protein synthesis or in cells cultivated in serum-free conditions. It is not known whether the effect of concanavalin A on 5'-nucleotidase depends upon the interiorizaiton of plasma membrane or is strictly associated with events at the cell surface.  (+info)

PETA-3/CD151, a member of the transmembrane 4 superfamily, is localised to the plasma membrane and endocytic system of endothelial cells, associates with multiple integrins and modulates cell function. (7/10563)

The Transmembrane 4 Superfamily member, PETA-3/CD151, is ubiquitously expressed by endothelial cells in vivo. In cultured human umbilical vein endothelial cells PETA-3 is present on the plasma membrane and predominantly localises to regions of cell-cell contact. Additionally, this protein is abundant within an intracellular compartment which accounts for up to 66% of the total PETA-3 expressed. Intracellular PETA-3 showed colocalisation with transferrin receptor and CD63 suggesting an endosomal/lysosomal localisation which was supported by immuno-electronmicroscopy studies. Co-immunoprecipitation experiments investigating possible interactions of PETA-3 with other molecules demonstrated associations with several integrin chains including beta1, beta3, beta4, (alpha)2, (alpha)3, (alpha)5, (alpha)6 and provide the first report of Transmembrane 4 Superfamily association with the (alpha)6beta4 integrin. Using 2-colour confocal microscopy, we demonstrated similar localisation of PETA-3 and integrin chains within cytoplasmic vesicles and endothelial cell junctions. In order to assess the functional implications of PETA-3/integrin associations, the effect of anti-PETA-3 antibodies on endothelial function was examined. Anti-PETA-3 mAb inhibited endothelial cell migration and modulated in vitro angiogenesis, but had no detectable effect on neutrophil transendothelial migration. The broad range of integrin associations and the presence of PETA-3 with integrins both on the plasma membrane and within intracellular vesicles, suggests a primary role for PETA-3 in regulating integrin trafficking and/or function.  (+info)

CFTR channel insertion to the apical surface in rat duodenal villus epithelial cells is upregulated by VIP in vivo. (8/10563)

cAMP activated insertion of the cystic fibrosis transmembrane conductance regulator (CFTR) channels from endosomes to the apical plasma membrane has been hypothesized to regulate surface expression and CFTR function although the physiologic relevance of this remains unclear. We previously identified a subpopulation of small intestinal villus epithelial cells or CFTR high expressor (CHE) cells possessing very high levels of apical membrane CFTR in association with a prominent subapical vesicular pool of CFTR. We have examined the subcellular redistribution of CFTR in duodenal CHE cells in vivo in response to the cAMP activated secretagogue vasoactive intestinal peptide (VIP). Using anti-CFTR antibodies against the C terminus of rodent CFTR and indirect immunofluorescence, we show by quantitative confocal microscopy that CFTR rapidly redistributes from the cytoplasm to the apical surface upon cAMP stimulation by VIP and returns to the cytoplasm upon removal of VIP stimulation of intracellular cAMP levels. Using ultrastructural and confocal immunofluorescence examination in the presence or absence of cycloheximide, we also show that redistribution was not dependent on new protein synthesis, changes in endocytosis, or rearrangement of the apical cytoskeleton. These observations suggest that physiologic cAMP activated apical membrane insertion and recycling of CFTR channels in normal CFTR expressing epithelia contributes to the in vivo regulation of CFTR mediated anion transport.  (+info)

The observation that over-expression of the EH domain or of the carboxy-terminal RalBP1 binding region of POB1/REPS2 results in a 30-40% reduction of EGF or insulin internalization has linked POB1 to the molecular machinery modulating regulated endocytosis [4]. More recently, it was reported that loss of POB1 expression during human prostate cancer progression, from androgen-dependent to growth factors dependent, results in loss of control of cell growth signaling while induced expression of POB1 causes a reduction of several EGF-responsive genes (e.g., Fos and Jun). In accordance, we find that an increase of POB1 isoform 2 expression correlates with a decrease of EGF-induced phosphorylation of Erk1-2 and Shc (Additional file 6). Moreover, POB1 isoform 2 down-regulation was observed during the progression of prostate cancer [7-9].. In our study we confirm the involvement of POB1 in EGF receptor endocytosis and we provide evidence for a functional role of the central proline-rich region. In fact, ...
A complete understanding of the molecular mechanisms of endocytosis requires the discovery and characterization of the protein machinery that mediates this aspect of membrane trafficking. A novel genetic screen was used to identify yeast mutants defective in internalization of bulk lipid. The fluorescent lipophilic styryl dye FM4-64 was used in conjunction with FACS to enrich for yeast mutants that exhibit internalization defects. Detailed characterization of two of these mutants, dim1-1 and dim2-1, revealed defects in the endocytic pathway. Like other yeast endocytosis mutants, the temperature-sensitive dim mutant were unable to endocytose FM4-64 or radiolabeled alpha-factor as efficiently as wild-type cells. In addition, double mutants with either dim1-delta or dim2-1 and the endocytosis mutants end4-1 or act1-1 displayed synthetic growth defects, indicating that the DIM gene products function in a common or parallel endocytic pathway. Complementation cloning of the DIM genes revealed identity ...
In mitosis, a dramatic decrease in endocytosis rate has been reported (Berlin et al., 1978). We repeated those observations (Fig. 1) using either fluorescent dextran or FM1-43 uptake as a measure of endocytosis rate by measuring the number of vesicles per cell and the total fluorescence intensity. With fluorescent dextran, the endocytosis rate normally decreased to ∼10% of interphase level in metaphase. FM1-43 is a water-soluble dye that is membrane impermeable, but it is readily incorporated into endocytic vesicles and is retained after cell fixation (Betz and Bewick, 1992; Terasaki, 1995). Fig. 1, b-e shows FM1-43 labeling of HeLa cells in various stages of mitosis in parallel with the DAPI staining patterns that enable rapid identification of mitotic phases in HeLa cells (Fig. 1, b-e, bottom). While interphase cells were brightly stained with FM1-43-labeled endocytic vesicles spread throughout the cytoplasm (low numerical aperture objectives were used to detect even out of focus vesicles), ...
The Slit diaphragm (SD) is the key filtration structure in human glomerular kidney that is affected in many types of renal diseases. SD proteins are known to undergo endocytosis and recycling to maintain the integrity of the filtration structure. However, the key components of this pathway remain unclear. Using the Drosophila nephrocyte as a genetic screen platform, we screened most genes involved in endocytosis and cell trafficking, and identified the key components of the cell trafficking pathway required for SD protein endocytosis and recycling. We discovered that the SD protein endocytosis and recycling pathway contains clathrin, dynamin, AP-2 complex, like-AP180 (Lap), auxilin and Hsc70-4 (the endocytosis part) followed by Rab11 and the exocyst complex (the recycling part). Disrupting any component in this pathway led to disrupted SD on the cell surface and intracellular accumulation of mislocalized SD proteins. We also showed the first in vivo evidence of trapped SD proteins in clathrin-coated
Endocytosis is an essential and well‐regulated process in higher eukaryotes [35], [51], [52]. Sustained neurotransmission imposes a greater demand on the precision and efficiency of endocytic pathways as vesicles are recycled locally to balance continued exocytosis [1], [2], [3]. While numerous players and regulators of endocytosis have been characterized in neurons [3], [13], [14], [15], inhibitors are rare. This work reveals the cellular function of Syt11 as a novel inhibitor in the vesicle retrieval pathways.. Using an RNAi approach, we revealed the function of Syt11 in neuronal endocytosis. Membrane capacitance recording to monitor the somatic exocytosis and endocytosis in DRG neurons showed that Syt11 KD greatly accelerated exo‐endocytosis, and this was often accompanied by an excessive membrane retrieval as evidenced by Cm overshoot, indicating an unbalanced coupling of endocytosis to exocytosis (Figs 1B-G and 3A-F). Furthermore, FM1‐43, dextran, and HRP uptake assays demonstrated an ...
TY - JOUR. T1 - Distinct endocytic responses of heteromeric and homomeric transforming growth factor β receptors. AU - Anders, Robert A.. AU - Arline, Sandra L.. AU - Doré, Jules J.E.. AU - Leof, Edward B.. PY - 1997/1/1. Y1 - 1997/1/1. N2 - Transforming growth factor β (TGFβ) family ligands initiate a cascade of events capable of modulating cellular growth and differentiation. The receptors responsible for transducing these cellular signals are referred to as the type I and type II TGFβ receptors. Ligand binding to the type II receptor results in the transphosphorylation and activation of the type I receptor. This heteromeric complex then propagates the signal(s) to down- stream effectors. There is presently little data concerning the fate of TGFβ receptors after ligand binding, with conflicting reports indicating no change or decreasing cell surface receptor numbers. To address the fate of ligand- activated receptors, we have used our previously characterized chimeric receptors ...
Metastasis is a multistep process requiring cancer cell signaling, invasion, migration, survival, and proliferation. These processes require dynamic modulation of cell surface proteins by endocytosis. Given this functional connection, it has been suggested that endocytosis is dysregulated in cancer. To test this, we developed In-Cell ELISA assays to measure three different endocytic pathways: clathrin-mediated endocytosis, caveolae-mediated endocytosis, and clathrin-independent endocytosis and compared these activities using two different syngeneic models for normal and oncogene-transformed human lung epithelial cells. We found that all endocytic activities were reduced in the transformed versus normal counterparts. However, when we screened 29 independently isolated non-small cell lung cancer (NSCLC) cell lines to determine whether these changes were systematic, we observed significant heterogeneity. Nonetheless, using hierarchical clustering based on their combined endocytic properties, we ...
A targeted variation of endocytosis employs receptor proteins in the plasma membrane that have a specific binding affinity for certain substances (Figure 3).. In receptor-mediated endocytosis, as in phagocytosis, clathrin is attached to the cytoplasmic side of the plasma membrane. If uptake of a compound is dependent on receptor-mediated endocytosis and the process is ineffective, the material will not be removed from the tissue fluids or blood. Instead, it will stay in those fluids and increase in concentration.. Some human diseases are caused by the failure of receptor-mediated endocytosis. For example, the form of cholesterol termed low-density lipoprotein or LDL (also referred to as bad cholesterol) is removed from the blood by receptor-mediated endocytosis. In the human genetic disease familial hypercholesterolemia, the LDL receptors are defective or missing entirely. People with this condition have life-threatening levels of cholesterol in their blood, because their cells cannot clear ...
Clathrin-mediated endocytosis is a critical process through which a wide variety of extracellular material is internalized. The primary component, clathrin, forms a cargo-selective lattice at the plasma membrane, as well as on endosomes and the TGN, though the cargo-selective components are incompletely defined. An ideal tool for understanding the spatio-temporal dynamics of both the clathrin coat and the cargo selected is total internal reflection fluorescence microscopy (TIR-FM), which permits selective imaging of events closely apposed to the ventral plasma membrane. Previously, observation of the clathrin coat has shown both static and dynamic populations, with some dynamic structures undergoing microtubule-dependent motion; the 70-110 nm decay constant of the TIR-FM field has led to the assumption that these are all representative of coated pits. Here, I demonstrate that the dynamic population of clathrin is primarily endosomal, as it lacks colocalization with the plasma membrane-specific ...
Purified MC3R Total GPCR Internalization Assay Kit from Creative Biomart. MC3R Total GPCR Internalization Assay Kit can be used for research.
Purified GLP1R Activated GPCR Internalization Assay Kit from Creative Biomart. GLP1R Activated GPCR Internalization Assay Kit can be used for research.
Endocytosis is a mechanism for cells to remove ligands, nutrients, and plasma membrane (PM) proteins, and lipids from the cell surface, bringing them into the cell interior. Transmembrane proteins entering through clathrin-dependent endocytosis (CDE) have sequences in their cytoplasmic domains that bind to the APs (adaptor-related protein complexes) and enable their rapid removal from the PM. In addition to APs and clathrin, there are numerous accessory proteins including dynamin. Depending on the various proteins that enter the endosome membrane, these cargoes are sorted to distinct destinations. Some cargoes, such as nutrient receptors, are recycled back to the PM. Ubiquitylated membrane proteins, such as activated growth-factor receptors, are sorted into intraluminal vesicles and eventually end up in the lysosome lumen via multivesicular endosomes (MVEs). There are distinct mechanisms of clathrin-independent endocytosis (CIE) depending upon the cargo and the cell type ...
TY - JOUR. T1 - LRP1-Dependent endocytic mechanism governs the signaling output of the bmp system in endothelial cells and in angiogenesis. AU - Pi, Xinchun. AU - Schmitt, Christopher E.. AU - Xie, Liang. AU - Portbury, Andrea L.. AU - Wu, Yaxu. AU - Lockyer, Pamela. AU - Dyer, Laura A.. AU - Moser, Martin. AU - Bu, Guojun D. AU - Flynn, Edward J.. AU - Jin, Suk Won. AU - Patterson, Cam. PY - 2012/8/17. Y1 - 2012/8/17. N2 - Rationale: Among the extracellular modulators of Bmp (bone morphogenetic protein) signaling, Bmper (Bmp endothelial cell precursor-derived regulator) both enhances and inhibits Bmp signaling. Recently we found that Bmper modulates Bmp4 activity via a concentration-dependent, endocytic trap-and-sink mechanism. Objective: To investigate the molecular mechanisms required for endocytosis of the Bmper/Bmp4 and signaling complex and determine the mechanism of Bmpers differential effects on Bmp4 signaling. Methods and Results: Using an array of biochemical and cell biology ...
There exist three kinds of endocytosis; receptor mediated endocytosis, pinocytosis and phagocytosis. First, receptor-mediated endocytosis is essential for targeted gene/drug delivery to a specific cell type. Second, pinocytosis is the engulfing and digestion of dissolved substances and phagocytosis is the engulfing and digestion of microscopically visible particles. In this study, we developed a capacitance sensor to monitor and distinguish three kinds of endocytosis in real time. The capacitance sensor is fabricated simple photolithography process on glass substrate and target cells are positioned between gap electrodes. The capacitance sensor was able to detect a capacitance peak in different cell lines during the internalization of adenoviruses or antibodies via receptor-mediated endocytosis. In contrast, the capacitance declined without a capacitance peak when nanoparticles were taken up via non-specific pinocytosis. In case of phagocytosis, the capacitance shows a peak during the engulfing of
Nature, 417(6888): 555-559. Vesicle pools Vesicle mobilization, docking, priming and fusion Three endocytic pathways The dynamic time course of endocytosis The time course of endoc3l;osis is regulated by stimulation Mechanisms that may regulate the time course of endocytosis Clathrin-dependent versus clathrin-independent endocytosis Regulation of endocytosis by single rate-limiting factors The effects of calcium on endocytosis Hypotheses that may account for calcium-mediated facilitation of endocytosis The functional significance of regulation of endoc3l;osis The contribution of slower endocytosis to short-term synaptic depression The maintenance of transmitter release by retrieving vesicles into the reserve pool and/or the readily releasable pool Is endocytosis fast enough to limit transmitter release from the fusion pore? Waldeck RF, Pereda A, Faber DS. 2000. Properties and plasticity of paired-pulse depression at a central synapse. J Neurosci, 20: 5312-5320. Wang LY, Kaczmarek LK. 1998. ...
Recent reports have suggested a role for microtubules in the endocytic process and pointed out the role for actin filaments for the early steps of apical endocytosis in polarized epithelial cells. However, these studies do not address the respective contribution of these two types of filaments along the endocytic pathway. In addition, several studies failed to demonstrate the role for actin filaments in clathrin dependent endocytosis in non polarized cells. In the present study we have investigated the role for both filaments in the endocytosis of two ligands internalized via clathrin coated pits (transferrin and alpha 2-macroglobulin) in a mouse hepatoma cell line. By immunocytochemical analysis with confocal microscopy, and biochemical analysis using a temperature sensitive step at 18 degrees C, we have shown that actin filaments are involved in two steps of the degradative pathway, and that microtubules are required at a stage in between. Actin filaments increase first, the uptake of ligands ...
The function of receptor-mediated endocytosis is diverse. It is widely used for the specific uptake of certain substances required by the cell (examples include LDL via the LDL receptor or iron via transferrin). The role of receptor-mediated endocytosis is well recognized up take downregulation of transmembrane signal transduction but can also promote sustained signal transduction.[3] The activated receptor becomes internalised and is transported to late endosomes and lysosomes for degradation. However, receptor-mediated endocytosis is also actively implicated in transducing signals from the cell periphery to the nucleus. This became apparent when it was found that the association and formation of specific signaling complexes is required for the effective signaling of hormones (e.g. EGF). Additionally it has been proposed that the directed transport of active signaling complexes to the nucleus might be required to enable signaling as random diffusion is too slow[4] and mechanisms permanently ...
article{69117807-3dd2-46c9-a208-5f5373157a52, abstract = {,p,High-content real-time imaging of hormone secretion in tissues or cell populations is a challenging task, which is unlikely to be resolved directly, despite immense translational value. We approach this problem indirectly, using compensatory endocytosis, a process that closely follows exocytosis in the cell, as a surrogate read-out for secretion. The tissue is immobilized in an open-air perifusion chamber and imaged using a two-photon microscope. A fluorescent polar tracer, perifused through the experimental circuit, gets trapped into the cells via endocytosis, and is quantified using a feature-detection algorithm. The signal of the tracer that accumulates into the endocytotic system reliably reflects stimulated exocytosis, which is demonstrated via co-imaging of the latter using existing reporters. A high signal-to-noise ratio and compatibility with multisensor imaging affords the real-time quantification of the secretion at the ...
Amphiphysin recruits dynamin to sites of endocytosis. Links to research on the mechanism of dynamin in vesicle scission and endocytosis. Research on proteins involved in clathrin-coated vesicle formation. Research on membrane bending. Research on protein-lipid interactions. Research on vesicle trafficking pathways. As a group we investigate vesicle budding using a variety of structural and functional approaches.
Cytosis is a transport mechanism for the movement of large quantities of molecules into and out of cells. There are three main types of cytosis: endocytosis (into the cell), exocytosis (out of the cell), and transcytosis (through the cell, in and out). The word cytosis (/saɪˈtoʊsɪs/) uses combining forms of cyto- and -osis, reflecting a cellular process. The term was coined by Novikoff in 1961. Endocytosis is when a cell absorbs molecules, such as proteins, from outside the cell by engulfing it with the cell membrane. It is used by most cells, because many critical substances are large polar molecules that cannot pass through the cell membrane. The two major types of endocytosis are pinocytosis and phagocytosis. Pinocytosis Pinocytosis, also known as cell drinking, is the absorption of small aqueous particles along with the membrane receptors that recognize them. It is an example of fluid phase endocytosis and is usually a continuous process within the cell. The particles are absorbed ...
Supplementary MaterialsFigure S1: Internalization assay. endosomes associated with dynamic actin assemblies. 3T6 cells stably expressing EGFP-fused -actin (green) were infected with Alexa Fluor 546-labeled MPyV (reddish) (MOI of 102 to 103 computer virus particles per cell) at 37C and scanned with T?=?4 s. Selected frames of cell at 45 min p.i. with corresponding transmission light images illustrate short-distance movement of virus-carrying endosomes associated with dynamic assemblies of EGFP-actin (observe Movie S3). White colored arrowheads point to MPyV virions. Arrows point to endosome-associated actin assemblies. Black arrowheads show MPyV-containing endosomes. Bars, 5 m. Cells were examined using a Leica TCS SP2 AOBS confocal microscope.(TIF) pone.0096922.s002.tif (4.6M) GUID:?75128633-6C0E-4733-829A-F64BA5BC7B02 Number S3: Intracellular distribution of fluorescently tagged transferrin during expression of Rab11 GTPase mutants. 3T6 cells expressing EGFP-fused wt, DN or CA version of Rab11 ...
In this study, we report the interaction of amphiphysin 2 with SNX4, a partnership that might be biologically relevant between endocytosis and endosomal trafficking. On one hand, amphiphysin 2 has been shown to be important for the early steps of endocytosis in mammalian cells (Wigge and McMahon, 1998). It is now well established that amphiphysin 2 helps to recruit dynamin via its C-terminal SH3 domain, at the site of clathrin-dependent endocytosis. It may also control membrane curvature either directly or indirectly through endophilin and the uncoating of clathrin-coated vesicles through synaptojanins. On the other hand, SNX4 belongs to a family of molecules initially characterized for their ability to bind membrane receptors such as EGF, PDGF, insulin or leptin receptors (Kurten et al., 1996; Haft et al., 1998). SNX molecules have been conserved throughout evolution and exist in yeast where Vps5p is the ortholog of human SNX1 (Horazdovsky, 1997). In yeast cells, Vps5p associates with other ...
Purpose: Myocilin has two distinct cellular distributions, cytoplasmic and membrane-associated, yet appears extracellularly. We have previously shown that myocilin is released from cells on exosomes, which are a component of the endosomal pathway. In this study we tested the hypothesis that myocilin enters the exosome pathway during plasma membrane receptor endocytosis.. Methods: Retinal pigment epithelia (RPE) in human eye-cups was stimulated with L-DOPA (1uM) to monitor endocytosis of GPR143 (OA1), an endogenous G-protein coupled receptor (GPCR) on the surface of RPE. Recombinant myocilin (WT, P370L and T377M) was heterologously co-expressed in transformed cells with GPR143 to test whether myocilin participates in receptor endocytosis and to determine the kinetics of binding. Cell surface proteins in eye-cups and transformed cells were biotinylated and protein trafficking and myocilin association were monitored over time using streptavidin beads. Finally, we tested myocilin binding to the ...
Tor2 is an activator of the Rom2/Rho1 pathway that regulates α-factor internalization. Since the recruitment of endocytic proteins such as actin binding proteins and the amphiphysins precedes the internalization of α-factor, I hypothesized that loss of Tor function leads to an alteration in the dynamics of the endocytic proteins. I report here that endocytic proteins, Abp1 and Rvs167, are less recruited to endocytic sites not only in tor2 but also tor1 mutants. Furthermore, I found that the endocytic proteins Rvs167 and Sjl2 are completely mistargeted to the cytoplasm in tor1∆tor2ts double mutant cells. I also demonstrate here that the efficiency of endocytic internalization or scission in all tor mutants was drastically decreased. In agreement with the Sjl2 mislocalization, I found that in tor1∆tor2ts double mutant cells, as well as other tor mutant cells, the overall PIP2 level was dramatically increased. Finally, the cell wall chitin content in tor2ts and tor1∆tor2ts mutant cells was also
In this study, we have described a new biochemical assay that efficiently reconstitutes the endocytosis of E-cadherin using the AJ plasma membranes. We have found here that non-trans-interacting E-cadherin is constitutively endocytosed like integrin (ligand-independent endocytosis), that the formation of endocytosed vesicles of E-cadherin is clathrin dependent, and that E-cadherin, but not other CAMs at AJs and TJs including nectins, claudins, and occludin, is selectively sorted into the endocytosed vesicles. Recent cell-level studies using chemical inhibitors have shown that E-cadherin might be internalized by clathrin- or caveolin-dependent endocytosis (Le et al., 1999; Akhtar and Hotchin, 2001; Palacios et al., 2002; Thomsen et al., 2002; Paterson et al., 2003; Ivanov et al., 2003). However, the results obtained in this way are indirect and not substantial because the low resolution indirect immunofluorescence staining could only follow the appearance of E-cadherin in large vesicular ...
TY - JOUR. T1 - Derailed endocytosis. T2 - An emerging feature of cancer. AU - Mosesson, Yaron. AU - Mills, Gordon. AU - Yarden, Yosef. PY - 2008/11/1. Y1 - 2008/11/1. N2 - Once engaged by soluble or matrix-anchored ligands, cell surface proteins are commonly sorted to lysosomal degradation through several endocytic pathways. Defective vesicular trafficking of growth factor receptors, as well as unbalanced recycling of integrin- and cadherin-based adhesion complexes, has emerged in the past 5 years as a multifaceted hallmark of malignant cells. In line with the cooperative nature of endocytic machineries, multiple oncogenic alterations underlie defective endocytosis, such as altered ubiquitylation (Cbl and Nedd4 ubiquitin ligases, for example), altered cytoskeletal interactions and alterations to Rab family members. Pharmaceutical interception of the propensity of tumour cells to derail their signalling and their adhesion receptors may constitute a novel target for cancer therapy.. AB - Once ...
Clathrin-mediated endocytosis involves the assembly of a network of proteins that select cargo, modify membrane shape and drive invagination, vesicle scission and uncoating. This network is initially assembled around adaptor protein (AP) appendage domains, which are protein interaction hubs. Using crystallography, we show that FxDxF and WVxF peptide motifs from synaptojanin bind to distinct subdomains on alpha-appendages, called top and side sites. Appendages use both these sites to interact with their binding partners in vitro and in vivo. Occupation of both sites simultaneously results in high-affinity reversible interactions with lone appendages (e.g. eps15 and epsin1). Proteins with multiple copies of only one type of motif bind multiple appendages and so will aid adaptor clustering. These clustered alpha(appendage)-hubs have altered properties where they can sample many different binding partners, which in turn can interact with each other and indirectly with clathrin. In the final coated
It is known for decades, and most recently seen in dynamin knockout mice, that endocytosis continues when classical mechanisms are blocked or deleted. With the help of ubiquitin, yeast live without clathrin and fungi reveal still other alternatives in the absence of clathrin. We discovered a few years ago that 50 percent of the cell surface of many cells can be removed in seconds by Ca-dependent endocytosis that requires no classical endocytic player. This response is unrelated to either apoptosis or autophagy; cell cultures survive and even flourish in the wake of this remodeling. This form of endocytosis, relying on no known adapter or cytoskeleton, can quantitatively remove PD-1 receptors from the T-cell surface membrane, receptors whose inactivation is a key to activating immune responses. Thus, domain-dependent endocytosis can be concentrative as well as contributing to overall fluid-phase endocytosis. As for exocytosis, Ca stress-dependent exocytosis can rapidly increase membrane area by ...
Zwiewka, M; Nodzynski, T; Robert, S; Vanneste, S; Friml, J, 2015: Osmotic Stress Modulates the Balance between Exocytosis and Clathrin-Mediated Endocytosis in Arabidopsis thaliana. MOLECULAR PLANT 8(8), p. 1175 - 1187, doi: 10.1016/j.molp.2015.03.007. Research Groups:. ...
Receptor-based endocytosis. Illustration of receptor-mediated endocytosis, where receptors on cells allow them to engulf target molecules (red). The target molecules are first shown outside the cell (centre left). They then bind (upper right) to receptor proteins (orange) on a cell membrane pit coated by the protein clathrin (yellow). The membrane pit forms a vesicle (lower right) around the molecules within the cell cytoplasm (blue). For three forms of endocytosis, see images C023/8787, C023/8789 and C023/8793. For exocytosis (the reverse process), see image C023/8796. For this artwork without labels, see image C023/8795. - Stock Image C023/8793
2014 Project discussion}} ,br> --[[User:Z8600021,Mark Hill]] ([[User talk:Z8600021,talk]]) 16:49, 20 March 2014 (EST) --[[User:Z3399239,Z3399239]] ([[User talk:Z3399239,talk]]) 16:49, 20 March 2014 (EST) --[[User:Z3420257,Z3420257]] ([[User talk:Z3420257,talk]]) 16:49, 20 March 2014 (EST) --[[User:Z3373930,Z3373930]] ([[User talk:Z3373930,talk]]) 16:50, 20 March 2014 (EST) Hello dear colleagues. Is anyone else interested in doing into the cell from the plasma membrane (Endocytosis)? --[[User:Z3399239,Z3399239]] ([[User talk:Z3399239,talk]]) 16:52, 20 March 2014 (EST) And if not Endocytosis would anyone be interested in doing from the trans Golgi network to the cell exterior (Exocytosis) ? --[[User:Z3399239,Z3399239]] ([[User talk:Z3399239,talk]]) 12:58, 27 March 2014 (EST) So would z3373930 research: CLIC/GEEC endocytic pathway and arf6-dependent endocytosis and z3420257 research: flotillin-dependent endocytosis and macropinocytosis and z3375490 research: circular doral ruffles and ...
The life cycle of an adenovirus is divided into early and late phases, separated by the DNA replication process. In the early phase, the virus attaches to a cell with its fibers. The penton base protein interacts with the host cell integrins, and the penton is internalized by the host cell through receptor-mediated endocytosis. The penton is disassembled as it is transported to the nucleus, where the viral particle releases its DNA. The viral DNA takes over as terminal protein attached to the end of the DNA strand initiates transcription. The early genes are responsible for making regulatory proteins, which alter the host proteins to prepare for DNA synthesis, activate other virus genes, and provide protection from the hosts immune system. Viral DNA replication now occurs. The late phase begins when the late genes are expressed during DNA replication. These genes produce proteins that are involved in virus particle assembly. The hosts cellular processes are shut down as transport of mRNA to ...
To obtain insights into the mechanism by which FCHo2 couples CCP growth and lifetime in CME, we analyzed the nanoscale localization of FCHo2 at CCPs. Dual-color SD-dSTORM (spectral demixing direct stochastic optical reconstruction microscopy) analysis of the distribution of endogenous FCHo2 within CCPs followed by quantitative averaging of ,250 images revealed a marked concentration of FCHo2 in ring-like structures (about 225 nm in diameter) at the outer rim of CCPs [consistent with (27)] while being largely absent from the CCP center (Fig. 3, D and E) that eventually gives rise to the dome as CCPs invaginate. Hence, FCHo2 selectively accumulates at the rim of CCPs, consistent with its early role in coupling CCP growth and dynamics.. Different models have been proposed regarding the early endocytic function of FCHo2. According to one model, FCHo2 nucleates CCPs by acting as a plasma membrane-associated recruitment hub for early-acting endocytic proteins bound to its μ-homology domain (20). This ...
Coronaviruses, including SARS-CoV-2, are proposed to use either the endocytic or non-endosomal pathway for cell entry (46). Our study provides biophysical evidence for the functionality of SLiMs in the cytoplasmic tails of ACE2 and integrin β3, which provide possible molecular links between the established (ACE2) and putative (integrin beta3) SARS-CoV-2 receptors and mediators of endocytosis and autophagy. Our finding that an endocytic AP2 μ2 binding motif exists in the ACE2 C-terminus and that such binding is negatively regulated by Tyr781 phosphorylation supports the possibility of clathrin-dependent endocytosis of SARS-CoV-2 upon receptor binding. It will, of course, be necessary to assess the biological relevance of the ACE2-AP2 μ2 interaction, particularly in light of its low affinity. Concerning the latter, we note that while affinities of AP2 core complexes for endocytic sorting signals are reported in the nanomolar range, measured KD values of the AP2 μ2 subunit alone vary between 10 ...
Background and Hypothesis: Recently, a study conducted by the Hundley lab revealed that mutation of a specific RNA editing protein, ADR2, in the model organism C. elegans increased receptor-mediated endocytosis of yolk protein vit-2 and oocyte maturation. Of interest to us was what additional RNA binding proteins were involved in the expression of vit-2. To this end, RNA interference (RNAi) was used to knock out relevant RNA binding proteins. We hypothesized we would find candidates that both enhanced and reduced the expression of vit-2.. Project Methods: Previously, adr-2(-) C. elegans strain expressing a yolk protein (vit-2) fused to GFP and a library of E. coli strains expressing RNAi directed to specific RNA binding proteins were engineered. vit-2:GFP reporter worms were grown on each RNAi bacterial strain. The COPAS Biosort, a large particle sorter which detects fluorescent intensity, was used to visualize and quantify vit-2 endocytosis.. Results: Our screen yielded ten candidate proteins. ...
Enlarged early endosomes in the neurons of young Down syndrome (DS) and pre-Alzheimers disease (AD) brains suggest that a disturbance in endocytosis is one of the earliest hallmarks of AD pathogenesis in both conditions. We identified a chromosome 21 gene, Intersectin-1 (ITSN1) that is up-regulated in DS brains and has a putative function in endocytosis and vesicle trafficking. To elucidate the function of ITSN1 and assess its contribution to endocytic defects associated with DS and AD, we generated Itsn1 null mice. In knockout mice we found alterations in a number of parameters associated with endocyic and vesicle trafficking events. We found a reduced number of exocytosis events in chromaffin cells and a slowing of endocytosis in neurons. Endosome size was increased in neurons and NGF levels were reduced in the septal region of the brain. Our data is the first indication that Itsn1 has a role in endocytosis in an in vivo mammalian model, and that a disruption in Itsn1 expression causes a ...
What is endocytosis? Here is a definite meaning, types , and process of endocytosis that is welll explained by our biology professors
hCTR1 is important not only because it is the major copper influx transporter but also because it mediates a significant component of the cellular accumulation of DDP. As one step toward identifying how hCTR1 transports DDP, we sought to determine the mechanism by which endogenously expressed hCTR1 is degraded following brief exposure to DDP using several different strategies for inhibiting endocytotic pathways and proteasomal degradation. The results support the conclusion that the initial step of DDP-induced loss of hCTR1 from human ovarian carcinoma cells is mediated by a process that is inhibited by amiloride but not by nystatin or methyl-β-cyclodextrin and is not dependent on either dynamin I or the Rac1 GTPase. Among the various endocytotic pathways currently defined, this pattern of inhibition most closely matches the process of macropinocytosis.. As currently understood, macropinocytosis occurs through the formation of large primary endocytotic vesicles in regions of membrane ruffling. ...
AP2-associated protein kinase 1 (Aak1) is a member of the Ark1/Prk1 subfamily of Ser/Thr protein kinases that are thought to regulate endocytosis by phosphorylating the accessory endocytic components. Aak1 interacts with and phosphorylates the mu2 subunit of the AP-2 complex, which promotes binding of the AP-2 to tyrosine based (Yxxf) internalization motif-containing receptors and subsequent receptor endocytosis. At least two isoforms of Aak1 are known to exist; the longer isoform contains an extended carboxy-terminus that contains an additional clathrin-binding domain. Overexpression of this long isoform or Aak1 depletion by RNA interference impairs transferrin recycling from the early/sorting endosome, suggesting that Aak1 functions at multiple steps of the endosomal pathway by regulating transferrin internalization and its recycling back to the plasma membrane. ...
Video articles in JoVE about clathrin coated vesicles include Applications of pHluorin for Quantitative, Kinetic and High-throughput Analysis of Endocytosis in Budding Yeast, Visualizing Clathrin-mediated Endocytosis of G Protein-coupled Receptors at Single-event Resolution via TIRF Microscopy, Measuring Synaptic Vesicle Endocytosis in Cultured Hippocampal Neurons, The Cell-based L-Glutathione Protection Assays to Study Endocytosis and Recycling of Plasma Membrane Proteins, Pulling Membrane Nanotubes from Giant Unilamellar Vesicles, In vivo and in vitro Studies of Adaptor-clathrin Interaction, Models and Methods to Evaluate Transport of Drug Delivery Systems Across Cellular Barriers, Methods for Cell-attached Capacitance Measurements in Mouse Adrenal Chromaffin Cell, Single-molecule Super-resolution Imaging of Phosphatidylinositol 4,5-bisphosphate in the Plasma Membrane with Novel Fluorescent Probes, Nitrogen Cavitation and Differential Centrifugation Allows for Monitoring the
Studies of membrane traffic between the cytoplasm and surface of a cell suggest that membrane internalization is tightly coupled to secretion. Studies using the capacitance technique show that endocytosis can follow evoked exocytosis within a second or less. The capacitance technique, however, measu …
Developmental regulation of apical endocytosis controls epithelial patterning in vertebrate tubular organs.s profile, publications, research topics, and co-authors
The molecular composition of plasma membranes is constantly remodeled by endocytosis and exocytosis. Eisosomes are large cytoplasmic protein assemblies that localize to specialized domains on the yeast plasma membrane. They are of uniform size and immobile, and their disruption leads to large aberrant plasma membrane invaginations and endocytic defects. It is unknown how eisosomes are formed or inherited and what governs their size, distribution, and location. Here we show that eisosomes are formed de novo in the bud of dividing cells. They colonize newly formed membrane at a fixed density in a polarized wave proceeding from the bud neck to the bud tip and become anchored at the site of their formation. Pil1, one of the two main eisosome subunits, emerges as the central regulator of eisosome biogenesis that determines both size and location of eisosomes. Lowering Pil1 expression leads to normal-sized eisosomes at a reduced density, suggesting that eisosomes must be of a minimal size. Conversely, ...
When sending chemical messages, cells release transmitters or hormones by Ca-triggered exocytosis. During exocytosis, the membrane of a secretory vesicle fuses...
Specific receptor-mediated endocytosis pathways can be investigated with fluorescent ligands including pHrodo™ dyes targeted to common receptors, including, EGF, LDL, and transferrin.. The most convenient, no-wash assay format uses pHrodo™ Red or pHrodo™ Green to allow discrimination of stages in the endocytic pathway from early endosome to lysosome formation with no quench or wash required.. pHrodo™ dyes are essentially non-fluorescent at neutral pH and exhibit increasing signal with a red or green readout respectively as the pH decreases. The increase in fluorescent signal can be used to monitor progression in the endocytic pathway.. ...
Sapreme, a biotechnology company focused on improving the delivery and efficacy of macromolecule therapeutics, today announced positive preclinical data on its proprietary endosomal escape platform in two presentations at the 16th Annual Meeting of the Oligonucleotide Therapeutics Society (OTS), held virtually from September 27th to 30th, 2020.. Sapreme is developing macromolecule delivery methods based on compounds that release therapeutic cargo from the endo-lysosome, improving access to intracellular targets and enhancing the therapeutic window for these therapeutics. Current macromolecular biologics rely on receptor-mediated endocytic uptake into the endosome and inefficient passive release from these vesicles into the cell to achieve therapeutic efficacy. The companys presentations demonstrate that Sapremes SPT001 compound improves intracellular release of targeted antisense oligonucleotides (ASOs) and thereby also their therapeutic efficacy. In addition to ASOs, SPT001 has also been ...
TY - JOUR. T1 - The SNARE proteins SNAP25 and synaptobrevin are involved in endocytosis at hippocampal synapses. AU - Zhang, Zhen. AU - Wang, Dongsheng. AU - Sun, Tao. AU - Xu, Jianhua. AU - Chiang, Hsueh Cheng. AU - Shin, Wonchul. AU - Wu, Ling Gang. PY - 2013/5/22. Y1 - 2013/5/22. N2 - SNAP25, an essential component of the soluble NSF (N-ethylmaleimide-sensitive factor) attachment protein receptor (SNARE) complex that mediates exocytosis, is not considered to play a role in endocytosis, which couples to exocytosis by retrieving a similar amount of exocytosed vesicles. By knocking down SNAP25 and imaging slow endocytosis at a conventional synapse, the rat cultured hippocampal synapse, we found that SNAP25 is involved in slow, clathrin-dependent endocytosis. With similar techniques, we found that not only SNAP25, but also synaptobrevin is involved in slow endocytosis. These results provide the first evidence showing the dual role of SNAP25 and synaptobrevin in both exocytosis and slow ...
UNC-51 overexpression can inhibit the transferrin endocytosis in the transfected COS-7 cells. We think that this inhibition of transferrin endocytosis should be caused by UNC-51-dependent...
article{1864472, abstract = {Endocytosis is a crucial mechanism by which eukaryotic cells internalize extracellular and plasma membrane material, and it is required for a multitude of cellular and developmental processes in unicellular and multicellular organisms. In animals and yeast, the best characterized pathway for endocytosis depends on the function of the vesicle coat protein clathrin. Clathrin-mediated endocytosis has recently been demonstrated also in plant cells, but its physiological and developmental roles remain unclear. Here, we assessed the roles of the clathrin-mediated mechanism of endocytosis in plants by genetic means. We interfered with clathrin heavy chain (CHC) function through mutants and dominant-negative approaches in Arabidopsis thaliana and established tools to manipulate clathrin function in a cell type-specific manner. The chc2 single mutants and dominant-negative CHC1 (HUB) transgenic lines were defective in bulk endocytosis as well as in internalization of ...
The heterotetrameric adaptor protein complex AP2 is one of the best-studied components of the endocytic machinery. The AP2 complex consists of four different subunits, α, β2, σ2, and μ2, which assemble into a core domain with two appendages (Fig. 2; Collins et al., 2002; Jackson et al., 2010). AP2 has multiple binding partners, including phosphatidylinositol 4,5-bisphosphate (PIP2), clathrin, several endocytic accessory proteins, and two signaling motifs present on some cargo receptors (see Traub, 2009 for a detailed review). The AP2 complex has classically been considered to be the master initiator of clathrin-mediated endocytosis through its role in recruiting clathrin molecules to the membrane. However, several lines of evidence question this idea.. If the AP2 complex has an essential role in initiation then its presence would be required for the formation of endocytic sites. However, in yeast the endocytosis of mating pheromone α-factor is unaffected in strains lacking functional AP2 ...
The potential for transcytosis (endocytosis → intracellular transport → exocytosis) of protein and membrane events associated with fluid phase and adsorptive endocytic processes within epithelia of the choroid plexus [blood-cerebrospinal fluid (CSF) barrier] were investigated in mice injected intravenously or into the lateral cerebral ventricle with native horseradish peroxidase (HRP) or the lectin wheatgerm agglutinin (WGA) conjugated to HRP. WGA binds to specific cell surface oligosaccharides and enters cells by the process of adsorptive endocytosis; native HRP is taken into cells non-specifically by fluid phase endocytosis. The lysosomal system of organelles and the endoplasmic reticulum, identified by enzyme cytochemical markers applied to choroid epithelia, were analysed for possible participation in transcytosis and compared to epithelial organelles harbouring the exogenous tracer proteins. Blood-borne native HRP was endocytosed readily by choroid epithelia whereas WGA-HRP was not, perhaps
article{f63aac35-6350-4bf7-866a-e224429f2246, abstract = {BACKGROUND: Galectin-3 (the Mac-2 antigen) is abundantly expressed in both macrophage like cells and certain non-macrophage cells. We have studied endocytosis of galectin-3 as one important step relevant for its function, and compared it between variants of a macrophage like cell line, and non-macrophage cells. ,br/,,br, ,br/,,br, METHODS: Endocytosis of galectin-3 was observed by fluorescence microscopy and measured by flow cytometry. The endocytosis mechanism was analysed using galectin-3 mutants, galectin-3 inhibitors and endocytic pathways inhibitors in the human leukaemia THP-1 cell line differentiated into naïve (M0), classical (M1) or alternatively activated (M2) macrophage like cells, and the non-macrophage cell lines HFL-1 fibroblasts and SKBR3 breast carcinoma. ,br/,,br, ,br/,,br, RESULTS: Galectin-3 endocytosis in non-macrophage cells and M2 cells was blocked by lactose and a potent galectin-3 inhibitor TD139, and also by the ...
The animation shows calcium-stimulated exocytosis of synaptic vesicles followed by clathrin-mediated vesicle recycling. Many of the molecular components that are involved in synaptic vesicle priming, docking, fusion, and endocytosis are shown. Although the process in the animation describes synaptic vesicle cycling, similar cellular processes occur for most calcium-coupled secretory and clathrin-mediated endocytotic events. The animation could be used to help illustrate the sequence of events associated with both exocytosis and endocytosis, as well as aid in understanding the processes involved in neurotransmitter release in response to nerve stimulation.. [Resource Details] ...
The animation shows calcium-stimulated exocytosis of synaptic vesicles followed by clathrin-mediated vesicle recycling. Many of the molecular components that are involved in synaptic vesicle priming, docking, fusion, and endocytosis are shown. Although the process in the animation describes synaptic vesicle cycling, similar cellular processes occur for most calcium-coupled secretory and clathrin-mediated endocytotic events. The animation could be used to help illustrate the sequence of events as. Published by Learning Registry #GoOpen. 4 Views, 0 Likes on Docs.com. #synapse #neuron #NSDL #NSDL_SetSpec_BEN #movie #signal transduction #endocytosis #Life Science
The central finding of the present study is that Mt3 plays a key role in the clathrin-dependent endocytosis of Aβ in astrocytes. In Mt3 −/− astrocytes, clathrin-mediated endocytosis, the mechanism responsible for Aβ endocytosis, was markedly decreased, whereas caveolin-mediated endocytosis was not altered. Astrocytes are likely key players in the clearance of extracellular Aβ; thus, our results suggest that changes in the Mt3 expression in astrocytes may have clinical relevance in AD. Taken together with our previous findings that Mt3 helps to maintain lysosomal degradation in astrocytes, the reduction in Mt3 in astrocytes may aggravate Aβ accumulation in the extracellular space.. Early studies showed that AD brain extracts induce more neurite outgrowth in cell cultures than do control brain extracts [27], suggesting upregulation of a growth-inducing factor or downregulation of a growth-inhibitory factor (GIF) in AD brains. The latter was shown to be the case, and a subsequent study ...
Link to Pubmed [PMID] - 20486136. Bioessays 2010 Jun;32(6):496-504. Clathrin and the endocytosis machinery has recently been described as being required in mammalian cells for the internalization of large particles including pathogenic bacteria, fungi, and large viruses. These apparently unexpected observations, within the framework of the classical mechanisms for the formation of clathrin-coated vesicles, are now considered as examples of a new non-classical function of clathrin, which can promote the internalization of membrane domains associated to planar clathrin lattices. The role of actin downstream of clathrin seems to be critical for this still poorly characterized process. The historical frontier between endocytosis and phagocytosis is vanishing in the light of this new role for clathrin.. http://www.ncbi.nlm.nih.gov/pubmed/20486136 ...
Looking for endocytic vacuole? Find out information about endocytic vacuole. A membrane-bound cellular organelle containing extracellular particles engulfed by the mechanisms of endocytosis Explanation of endocytic vacuole
PathHunter® Receptor Tyrosine Kinase (RTK) Internalization Assays are nonimaging, non-antibody based chemiluminescent detection assays that provide a direct and quantitative measurement of internalized RTKs localized to early endosomes. Your PathHunter Receptor Tyrosine Kinase Internalization Cell Line, when used in conjunction with a PathHunter Detection Kit (DiscoveRx, Cat. #93-0001 Series), provides a cell-based functional assay for receptor tyrosine kinase internalization. ...
Efficient non-viral gene delivery often involves the conjugation of a cell-specific ligand to the vector, which directs the vector to its intended target through binding to a cellular receptor followed by internalization via endocytosis. However, little is known in terms of how the various endocytosis pathways affect the performance of the delivery vehicle. Previously, the Pack lab has demonstrated that caveolin-mediated endocytosis is important to in vitro polyethylenimine (PEI)- and polyamidoamine (PAMAM)-mediated gene delivery in HeLa cells through the use of small molecule drugs and small-interfering RNA [1-2]. The goal of this thesis is to further elucidate the effects of cellular uptake mechanism on non-viral gene delivery in vitro and in vivo utilizing a small hairpin RNA (shRNA) Tet-on system. Specifically, we have investigated the effects of clathrin-dependent endocytosis and caveolin-dependent endocytosis on the efficacy of PEI and PEI-derivative gene delivery in HeLa and MDA-MB-231 ...
Adapter protein that functions as clathrin-associated sorting protein (CLASP) required for clathrin-mediated endocytosis of selected cargo proteins. Can bind and assemble clathrin, and binds simultaneously to phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) and cargos containing non-phosphorylated NPXY internalization motifs, such as the LDL receptor, to recruit them to clathrin-coated pits. Can function in clathrin-mediated endocytosis independently of the AP-2 complex. Involved in endocytosis of integrin beta-1; this function seems to redundant with the AP-2 complex and seems to require DAB2 binding to endocytosis accessory EH domain-containing proteins such as EPS15, EPS15L1 and ITSN1. Involved in endocytosis of cystic fibrosis transmembrane conductance regulator/CFTR. Involved in endocytosis of megalin/LRP2 lipoprotein receptor during embryonal development. Required for recycling of the TGF-beta receptor. Involved in CFTR trafficking to the late endosome. Involved in several receptor-mediated
Membrane vesicle traffic to and from the plasma membrane is essential for cellular homeostasis in all eukaryotes. In plants, constitutive traffic to and from the plasma membrane has been implicated in maintaining the population of integral plasma-membrane proteins and its adjustment to a variety of hormonal and environmental stimuli. However, direct evidence for evoked and selective traffic has been lacking. Here, we report that the hormone abscisic acid (ABA), which controls ion transport and transpiration in plants under water stress, triggers the selective endocytosis of the KAT1 K+ channel protein in epidermal and guard cells. Endocytosis of the K+ channel from the plasma membrane initiates in concert with changes in K+ channel activities evoked by ABA and leads to sequestration of the K+ channel within an endosomal membrane pool that recycles back to the plasma membrane over a period of hours. Selective K+ channel endocytosis, sequestration, and recycling demonstrates a tight and dynamic ...
Recently, several theoretical and computational studies have also been performed to investigate the membrane wrapping efficiency of elastic NPs during endocytosis, which has been shown regulated synergistically by NP size, shape, and elasticity (22, 23, 33). However, despite the fact that the effects of NP elasticity on different endocytic uptake mechanisms have been experimentally explored in this work, the theoretical modeling of these uptake mechanisms remains challenging. More thorough and realistic modelings with explicit consideration of the actin network and adaptor proteins underneath the cell membrane are called for. Clathrin- and caveolin-independent endocytosis can be modeled using a membrane wrapping based on the Helfrich-Canham membrane theory (34), suggesting that stiff NPs are energetically more prone to full wrapping than soft ones (21). This elasticity effect on the simple membrane wrapping of an NP gradually becomes less significant as the NP elasticity increases. For isotropic ...
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Endocytotic uptake of HPMA-based polymers by different cancer cells: impact of extracellular acidosis and hypoxia Daniel Gündel,1 Mareli Allmeroth,2 Sarah Reime,1 Rudolf Zentel,2 Oliver Thews1 1Institute of Physiology, Martin Luther University Halle-Wittenberg, Halle (Saale), 2Institute of Organic Chemistry, Johannes Gutenberg-University, Mainz, Germany Background: Polymeric nanoparticles allow to selectively transport chemotherapeutic drugs to the tumor tissue. These nanocarriers have to be taken up into the cells to release the drug. In addition, tumors often show pathological metabolic characteristics (hypoxia and acidosis) which might affect the polymer endocytosis.Materials and methods: Six different N-(2-hydroxypropyl)methacrylamide (HPMA)-based polymer structures (homopolymer as well as random and block copolymers with lauryl methacrylate containing hydrophobic side chains) varying in molecular weight and size were analyzed in two different tumor models. The cellular uptake of fluorescence
The ClC-5 chloride channel resides mainly in vesicles of the endocytotic pathway and contributes to their acidification. Its disruption in mice entails a broad defect in renal endocytosis and causes secondary changes in calciotropic hormone levels. Inactivating mutations in Dents disease lead to proteinuria and kidney stones. Possibly by recycling, a small fraction of ClC-5 also reaches the plasma membrane. Here we identify a carboxyl-terminal internalization motif in ClC-5. It resembles the PY motif, which is crucial for the endocytosis and degradation of epithelial Na+ channels. Mutating this motif increases surface expression and currents about 2-fold. This is probably because of interactions with WW domains, because dominant negative mutants of the ubiquitin-protein ligase WWP2 increased surface expression and currents of ClC-5 only when its PY motif was intact. Stimulating endocytosis by expressing rab5 or its GTPase-deficient Q79L mutant decreased WT ClC-5 currents but did not affect ...
All corticosteroid hormones share cholesterol as a common precursor. Therefore, the first step in steroidogenesis is cholesterol uptake or synthesis. Cells that produce steroid hormones can acquire cholesterol through two paths. The main source is through dietary cholesterol transported via the blood as cholesterol esters within low density lipoproteins (LDL). LDL enters the cells through receptor-mediated endocytosis. The other source of cholesterol is synthesis in the cells endoplasmic reticulum. Synthesis can compensate when LDL levels are abnormally low.[4] In the lysosome, cholesterol esters are converted to free cholesterol, which is then used for steroidogenesis or stored in the cell.[29]. The initial part of conversion of cholesterol into steroid hormones involves a number of enzymes of the cytochrome P450 family that are located in the inner membrane of mitochondria. Transport of cholesterol from the outer to the inner membrane is facilitated by steroidogenic acute regulatory protein ...
Nano-meter sized particles of de-aluminated zeolite Y has a high adsorption capacity of both low molecular weight bio-molecules and macromolecules. In this study we used de-aluminated zeolite Y as a novel approach to study the mechanisms of endocytosis in immature human peripheral blood dendritic cells (DCs). Probes detecting pH neutral and acidic endosomes were adsorbed to the zeolite and used as a tracer of the endosomal pathway of a cell in the form of acidification and lysosomal function. Both the myeloid (M-DCs) and the plasmacytoid (P-DCs) dendritic cell subsets showed an endocytosing capacity comparable to peripheral blood monocytes but only the M-DCs were able to form acidic endosomes after internalization of zeolite particles. Furthermore, during lipopolysaccharide (LPS) stimulation of the DCs population, an enhanced induction of acidic endosomes was only seen in the M-DC population. Proteolytic degradation of endocytosed proteins was detected using self-quenched DQ-ovalbumin adsorbed ...
Quantitative fluorescence spectroscopy and flow cytometry analyses of cell-penetrating peptides internalization pathways: optimization, pitfalls, comparison with mass spectrometry quantification, Scientific Reports 6, 36938 (2016). Since their discovery twenty years ago, cell-penetrating peptides (CPPs) or protein transduction domains (PTDs) have been described as promising drug delivery systems. There are increasing numbers of successful applications of CPPs/PTDs in vivo. However, one of the limitations to their wide and diverse application is the diversity of their uptake pathways. The CPP and its cargo may end up free in the cytosol and reach their biological target only following translocation, but remain confined in intracellular vesicles after endocytosis, unless subsequent events such as endosomal rupture occur. Along with the development of CPPs/PTDs as vectors to carry various macromolecules for targeted cellular therapies, engineering new CPPs/PTDs with optimized transport and ...
Endocytosis by African trypanosomes. I. Three dimensional structure of the endocytic organelles in Trypanosoma brucei and Trypanosoma ...
Clathrin-mediated endocytosis regulates the signalling activity and turnover of multiple plasma membrane proteins. Interfering with endocytosis can therefore have complex effects on developmental processes. William Sessa and colleagues (p. 1465) investigate the role of the Dynamin 2 (Dnm2) GTPase - a key component of the endocytic machinery - during angiogenesis in mice. Using endothelial cells in culture, they find that downregulation of Dnm2 impairs angiogenesis, even though vascular endothelial growth factor (VEGF) signalling is enhanced - due to increased surface levels of the receptor. This is in contrast to previous work suggesting that endocytosis might promote VEGF signalling. The authors ascribe the Dnm2 knockdown-induced defect in vessel formation at least partially to disrupted integrin turnover: focal adhesion size is increased and inactive integrin receptors appear to accumulate on the cell surface. Importantly, these observations hold true in vivo: conditional deletion of Dnm2 in ...
TY - JOUR. T1 - Ligand-bound quantum dot probes for studying the molecular scale dynamics of receptor endocytic trafficking in live cells. AU - Sundara Rajan, Sujata. AU - Liu, Hong Yan. AU - Vu, Tania Q.. PY - 2008/6/1. Y1 - 2008/6/1. N2 - Endocytic receptor trafficking is a complex, dynamic process underlying fundamental cell function. An integrated understanding of endocytosis at the level of single or small numbers of ligand bound-receptor complexes inside live cells is currently hampered by technical limitations. Here, we develop and test ligand nerve growth factor-bound quantum dot (NGF-QD) bioconjugates for imaging discrete receptor endocytic events inside live NGF-responsive PC12 cells. Using single particle tracking, QD hybrid gel coimmunoprecipitation, and immunocolocalization, we illustrate and validate the use of QD-receptor complexes for imaging receptor trafficking at synchronized time points after QD-ligand - receptor binding and internalization (t = 15-150 min). The unique value ...
On Some Aspects of the Thermodynamic of Membrane Recycling Mediated by Fluid Phase Endocytosis: Evaluation of Published Data and ...
The lipid mediator sphingosine 1-phosphate (S1P) regulates a wide range of cellular activities, including vascular maturation, angiogenesis, and immune-cell trafficking. Among the five known receptors for S1P (S1PR1-S1PR5), S1PR1 is a critical regulator of lymphocyte trafficking: its signaling is required for lymphocyte egress from lymphoid organs, while its down-modulation by agonist-induced internalization is a prerequisite for lymphocyte entry into lymphoid organs from the bloodstream. Despite the importance of S1PR1 down-regulation in determining lymphocyte behavior, the molecular mechanism of its internalization in lymphocytes has not been defined. Here we show that agonist-induced S1PR1 internalization in T cells occurs via clathrin-mediated endocytosis and is regulated by moesin, an ezrin-radixin-moesin (ERM) family member. In S1P-stimulated T cells, S1PR1 relocalized within clathrin-coated vesicles (CCVs) and early endosomes, and S1PR1 internalization was blocked when clathrin was
Ligand-induced endocytosis of receptor tyrosine kinases (RTKs) is a dynamic process governed by numerous protein-protein and protein-lipid interactions. This is a major mechanism of signal termination and is also frequently impaired in cancer. The Cbl family of ubiquitin ligases has been shown to play a key role in downregulation of RTKs, by directing their ligand-induced ubiquitination and subsequent lysosomal degradation. My thesis work has led to the identification of novel, ubiquitin-ligase independent, functions of Cbl in receptor endocytosis. We demonstrated that the adaptor protein CIN85 links Cbl with epidermal growth factor receptor (EGFR) internalization. The three SH3 domains of CIN85 interact with Cbl/Cbl-b in a phosphotyrosine dependent manner, whereas its proline-rich region constitutively binds endophilins, known regulators of plasma membrane invagination. The SH3 domains of CIN85 recognize an atypical proline-arginine (PxxxPR) motif present in Cbl and Cbl-b. Moreover, we showed ...
The adaptor protein beta-arrestin2 enhances endocytosis of the low density lipoprotein receptor.: Endocytosis of the low density lipoprotein (LDL) receptor (LDL
Regulation of synaptic transmission is a widespread means for dynamic alterations in nervous system function. In several cases, this regulation targets vesicular recycling in presynaptic terminals and may result in substantial changes in efficiency of synaptic transmission. Traditionally, experimental accessibility of the synaptic vesicle cycle in central neuronal synapses has been largely limited to the exocytotic side, which can be monitored with electrophysiological responses to neurotransmitter release. Recently, physiological measurements on the endocytotic portion of the cycle have been made possible by the introduction of styryl dyes such as FM1-43 as fluorescent markers for recycling synaptic vesicles. Here we demonstrate the existence of fast endocytosis in hippocampal nerve terminals and derive its kinetics from fluorescence measurements using dyes with varying rates of membrane departitioning. The rapid mode of vesicular retrieval was greatly speeded by exposure to staurosporine or ...
Probable lipid-binding protein with higher affinity for phosphatidic acid, a lipid enriched in recycling endosome membranes. On endosome membranes, may act as a downstream effector of Rab proteins recruiting cytosolic proteins to regulate membrane tubulation. May be involved in a late step of receptor-mediated endocytosis regulating for instance endocytosed-EGF receptor trafficking. Alternatively, may regulate slow endocytic recycling of endocytosed proteins back to the plasma membrane. May indirectly play a role in neurite outgrowth.
Drug-dependent neural plasticity related to drug addiction and schizophrenia can be modeled in animals as behavioral sensitization, which is induced by repeated noncontingent or self-administration of many drugs of abuse. Molecular mechanisms that are critical for behavioral sensitization have yet to be specified. Long-term depression (LTD) of alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid receptor (AMPAR)-mediated synaptic transmission in the brain has been proposed as a cellular substrate for learning and memory. The expression of LTD in the nucleus accumbens (NAc) required clathrin-dependent endocytosis of postsynaptic AMPARs. NAc LTD was blocked by a dynamin-derived peptide that inhibited clathrin-mediated endocytosis or by a GluR2-derived peptide that blocked regulated AMPAR endocytosis. Systemic or intra-NAc infusion of the membrane-permeable GluR2 peptide prevented the expression of amphetamine-induced behavioral sensitization in the rat. ...
Image:exo_endo_cytosis.jpg,300px,thumb,right,Exocytosis and Endocytosis cartoon]] == Cell Import - Endocytosis == [[Image:Endocytosis types.png,thumb,300px,Endocytosis types]] This lecture introduces how substances that are imported (endocytosis) and processed by the cell. Notes in Preparation (notice removed when complete) There are a number of processes by which the cell can absorb substances. The two main forms are by endocytosis or phagocytosis. Absorbed substances include: substances required for cell growth, cell signaling toxic chemicals and drugs, bacteria and viruses. In addition, this is the main method for membrane removal and recycling. We will study this topic at the level of the cellular components and organelles involved in the process: endosomes, lysosomes, peroxisomes, transport vesicles, Golgi apparatus and endoplasmic reticulum. :Movie [[Media:JCB200109030.v2.mov,Vesicles Display Bidirectional Motility along Microtubules]] Visualization of Rab9-mediated vesicle transport ...
Clathrin-mediated endocytosis involves cargo selection and membrane budding into vesicles with the aid of a protein coat. Formation of invaginated pits on the plasma membrane and subsequent budding of vesicles is an energetically demanding process that involves the cooperation of clathrin with many different proteins. Here we investigate the role of the brain-enriched protein epsin 1 in this process. Epsin is targeted to areas of endocytosis by binding the membrane lipid phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P(2)). We show here that epsin 1 directly modifies membrane curvature on binding to PtdIns(4,5)P(2) in conjunction with clathrin polymerization. We have discovered that formation of an amphipathic alpha-helix in epsin is coupled to PtdIns(4,5)P(2) binding. Mutation of residues on the hydrophobic region of this helix abolishes the ability to curve membranes. We propose that this helix is inserted into one leaflet of the lipid bilayer, inducing curvature. On lipid monolayers epsin alone is
Parkinsons disease (PD) is linked to impaired degradation and accumulation of the misfolded protein, alpha-synuclein. Therefore, accelerating the degradation of alpha-synuclein is of therapeutic interest. Our lab has tested the hypothesis that α-synuclein uses endocytosis as a route to the lysosome for its degradation. We have found evidence that several endocytosis genes regulate α-synucleins PD related properties. Most importantly, the absence of vps28 increases α-synuclein aggregation and cellular accumulation, and confers toxicity in a yeast PD model. I, specifically, found that increasing the concentration of α-synuclein in yeast that lack vps28 further enhances each of these pathological characteristics.
Here, we describe an approach to directly visualize the activity of proteases that are incorporated into the phagosome at different stages of maturation. Only small numbers of phagocytes are required and there is no need to isolate individual endosomal compartments before analysis. This method is sensitive enough to allow an examination of primary cultures of professional APC, including DCs. Furthermore, the use of covalent active site-directed probes in conjunction with electrophoresis ensures specificity. Methods that employ fluorogenic substrates to detect protease activity suffer from the drawback that more than one enzyme can usually cleave a given peptide substrate. Analysis of the delivery of active hydrolases to the phagosome helped clarify both the distribution of cysteine protease activities among the different endocytic organelles and the dynamics of phagosomal maturation in primary cultures of professional APCs.. We validated our method of in vivo labeling of phagosomal proteolytic ...
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Failure of trabecular myocytes to undergo appropriate cell cycle withdrawal leads to ventricular noncompaction and heart failure. Signaling of growth factor receptor ERBB2 is critical for myocyte proliferation and trabeculation. However, the mechanisms underlying appropriate downregulation of trabecular ERBB2 signaling are little understood. Here, we have found that the endocytic adaptor proteins NUMB and NUMBL were required for downregulation of ERBB2 signaling in maturing trabeculae. Loss of NUMB and NUMBL resulted in a partial block of late endosome formation, resulting in sustained ERBB2 signaling and STAT5 activation. Unexpectedly, activated STAT5 overrode Hippo-mediated inhibition and drove YAP1 to the nucleus. Consequent aberrant cardiomyocyte proliferation resulted in ventricular noncompaction that was markedly rescued by heterozygous loss of function of either ERBB2 or YAP1. Further investigations revealed that NUMB and NUMBL interacted with small GTPase Rab7 to transition ERBB2 from ...
One unique aspect of VEGFR2 endocytosis is its regulation by several transmembrane and cytosolic interacting proteins, which play a role in either VEGFR2 internalization or degradation. A group of such proteins involved in VEGFR2 internalization is Dab2, ephrin-B2, and PAR-3. Dab2,46 a clathrin-associated sorting protein, and the cell polarity regulator PAR-3 interact with the transmembrane protein ephrin-B2 and VEGFR2. Disruption of this interaction by silencing of Dab2 or PAR-3 causes reduced VEGFR2 internalization and impaired VEGF-induced angiogenesis. After RTKs are internalized into early endosomes, a proportion of the receptors is modified by ubiquitin and then sorted for lysosomal degradation. CCM347 and myoferlin,48 respectively, associate with VEGFR2 in ECs and serve to enhance VEGFR2 stability by preventing receptor degradation.. Apart from internalization and degradation, VEGFR2 signaling is regulated by protein tyrosine phosphatases (PTPs), such as VE-PTP and PTP1b. VE-PTP is a ...
set by micropipette aspiration to be less than 1 over a wide range of spontaneous curvatures, indicating a high membrane-tension regime in their set up. Thus, our model is consistent with their observations of shallow buds observed in isotonic conditions. One result that our model cannot explain is the lack of any clathrin assembly observed under hypotonic conditions. It is possible that at extremely high membrane tensions, the coat is simply unable to stay bound to the membrane at the extremely flat morphology that would be expected.. Avinoam et al. (46) found that the size of the clathrin coat does not change substantially during membrane deformation in CME in human skin melanoma (SK-MEL-2) cells. This observation is in contrast to the canonical view that the clathrin coat should directly impose its preferred curvature on the underlying membrane (8). There are two possible explanations for this observation in the context of our study. One is that the membrane tension is too high for the coat ...
The early events in the infection of normal B lymphocytes and B lymphoblastoid cells by Epstein-Barr virus (EBV) were examined by electron and immunoelectron microscopy and by infectivity and inhibition studies. Purified EBV remained on the cell surface at 4 degrees and appeared as 250-nm ovoid particles in contact with the cell membrane through 50-nm envelope projections. Internalization of EBV in normal B lymphocytes into large (300-500 nm) uncoated vacuoles was initiated within 2 to 5 min at 37 degrees. At this stage approximately 1/3 of cell-associated virus was located in cellular invaginations while another 1/3 was in cell vacuoles. Direct fusion of EBV with the outer cell membrane was not observed. Instead, viral deenvelopment and nucleocapsid transit into the cytoplasm occurred from the large endocytic vesicles within 15 to 30 min at 37 degrees and did not involve lysosomal enzymes. During this time, the viral envelope became amorphous and its separation from the nucleocapsid was ...
... at biologyreference.com Endocytosis - researching endocytic mechanisms at endocytosis.org Clathrin-mediated ... It was recently found that an eisosome serves as a portal of endocytosis in yeast. The major route for endocytosis in most ... Endocytosis pathways can be subdivided into four categories: namely, receptor-mediated endocytosis (also known as clathrin- ... Stage 1 Stage 2 Stage 3 Endocytosis animation (1) Endocytosis animation (2) Active transport Emperipolesis RAP6 (Rab5- ...
Without Notch trans-endocytosis, there would be too many neurons in a developing embryo. Trans-endocytosis is also involved in ... Trans-endocytosis from neurons to glia has been observed using time-lapse microscopy. Trans-endocytosis also applies to ... Trans-endocytosis is the biological process where material created in one cell undergoes endocytosis (enters) into another cell ... For example, this process is involved when a part of the protein Notch is cleaved off and undergoes endocytosis into its ...
... refers to a form of endocytosis of synaptic vesicles at nerve terminals. In bulk endocytosis, compared to ... Clathrin-mediated endocytosis and bulk endocytosis appear to occur concurrently in highly active synaptic terminals. The ... Pinocytosis Endocytosis Phagocytosis BAR domain syndapin Qualmann B, Koch D, Kessels MM (2011). "Let's go bananas: revisiting ... Bulk endocytosis is activated specifically during intense stimulation, such as during high-frequency trains of action ...
... (RME), also called clathrin-mediated endocytosis, is a process by which cells absorb metabolites ... clathrin-mediated endocytosis remains the best studied. Clathrin-mediated endocytosis of many receptor types begins with the ... adsorptive pinocytosis Pinocytosis Phagocytosis Viropexis Bulk endocytosis Endocytosis Sorkin A, Puthenveedu MA (2013-01-01). " ... However, receptor-mediated endocytosis is also actively implicated in transducing signals from the cell periphery to the ...
... (FEME) is an endocytic pathway found in eukaryotic cells. It requires the activity of ... Rennick JJ, Johnston AP, Parton RG (March 2021). "Key principles and methods for studying the endocytosis of biological and ... "Molecular mechanism of Fast Endophilin-Mediated Endocytosis". The Biochemical Journal. 477 (12): 2327-2345. doi:10.1042/ ...
Within the intestine of the host, Chilomastix trophozoites feed via endocytosis. This brings the particles into the cell and ... Trophozoites feed on the host's intestinal contents such as bacteria through endocytosis. Once the intestinal contents begin to ... doi:10.1111/j.1550-7408.1973.tb03577.x. Martin, Elizabeth; Hine, Robert (2015). "Endocytosis". A Dictionary of Biology. Oxford ... involved in the function of endocytosis, enabling the movement of food particles towards the feeding groove. The flagella ...
Endocytosis and exocytosis are both forms of bulk transport that move materials into and out of cells, respectively, via ... Viruses enter cells through a form of endocytosis that involves their outer membrane fusing with the membrane of the cell. This ... In the case of endocytosis, the cellular membrane folds around the desired materials outside the cell. The ingested particle ... ISBN 978-0-321-77565-8. Transport into the Cell from the Plasma Membrane: Endocytosis - Molecular Biology of the Cell - NCBI ...
Receptor-mediated endocytosis Receptor-mediated endocytosis is a mode of pinocytosis. Proteins in the clathrin coat on the ... Endocytosis is when a cell absorbs a molecule, such as a protein, from outside the cell by engulfing it with the cell membrane ... It is an example of fluid phase endocytosis and is usually a continuous process within the cell. The particles are absorbed ... There are three main types of cytosis: endocytosis (into the cell), exocytosis (out of the cell), and transcytosis (through the ...
"Cohn's discoveries on endocytosis in macrophages have proved fundamental to cell biology, since endocytosis is a process ... Endocytosis and the recycling of plasma membrane. J. Cell Biol. 96:1-27. 1986 With A. A. Aderem, D. S. Cohen, and S. D. Wright ... Endocytosis. Annu. Rev. Biochem. 46:669-722. 1978 With N. Nogueira. Trypanosoma cruzi: In vitro induction of macrophage ... moving beyond endocytosis to study macrophages' secretions and identifying more than 50 products of macrophages that play " ...
Marsh M (2001). Endocytosis. Oxford University Press. p. vii. ISBN 978-0-19-963851-2. Hetzer MW (March 2010). "The nuclear ... Many cells ingest food and other materials through a process of endocytosis, where the outer membrane invaginates and then ... with the development of endocytosis, whereas mitochondria were acquired by ingestion as endosymbionts. The syntrophic ...
In animals, vacuoles serve in exocytosis and endocytosis processes. Endocytosis refers to when substances are taken into the ... Cooper G (2000). "Endocytosis". The Cell: A Molecular Approach. Sinauer Associates, Inc. Retrieved 2008-12-09. Lodish H, et al ... There are two types of endocytosis, phagocytosis (cell eating) and pinocytosis (cell drinking). In phagocytosis, cells engulf ...
Endocytosis. In: Cuatrecasas P, Greaves MF, eds. Receptors and Recognition. London: Chapman & Hall, 1977:105-41. 26. Stossel TP ... Filamin A interaction with the CXCR4 third intracellular loop regulates endocytosis and signaling of WT and WHIM-like receptors ...
Binding to αv integrin results in endocytosis of the virus particle via clathrin-coated pits. Attachment to αV integrin ... Meier O, Greber UF (February 2004). "Adenovirus endocytosis". The Journal of Gene Medicine. 6 (Suppl 1): S152-63. doi:10.1002/ ... stimulates cell signaling and thus induces actin polymerization, which facilitates clathrin-mediated endocytosis, and results ...
The endocytosis and exocytosis of vesicles allows cells to communicate, to transfer nutrients, to import signaling receptors, ... MBInfo - Clathrin Mediated Endocytosis Eukaryotic Linear Motif resource motif class LIG_Clathr_ClatBox_1 Eukaryotic Linear ... Clathrin-mediated endocytosis (CME) regulates many cellular physiological processes such as the internalization of growth ... Review on involvement of clathrin in plant endocytosis) Royle SJ, Bright NA, Lagnado L (April 2005). "Clathrin is required for ...
Kotowski SJ, Hopf FW, Seif T, Bonci A, von Zastrow M (July 2011). "Endocytosis promotes rapid dopaminergic signaling". Neuron. ... "EHD Home Page: An ATPase involved in membrane remodelling". www.endocytosis.org. Retrieved 2016-10-15. "Help - Homo_sapiens - ...
1999). "Dynamin II is involved in endocytosis but not in the formation of transport vesicles from the trans-Golgi network". J. ... They have been implicated in cell processes such as endocytosis and cell motility, and in alterations of the membrane that ... Sever S (2003). "Dynamin and endocytosis". Curr. Opin. Cell Biol. 14 (4): 463-7. doi:10.1016/S0955-0674(02)00347-2. PMID ... Lundmark R, Carlsson SR (Nov 2003). "Sorting nexin 9 participates in clathrin-mediated endocytosis through interactions with ...
DENV undergoes endocytosis. Acidification of the endosome leads to a conformational change of E, exposing a fusion peptide ...
Formins regulate endocytosis. mDia 1 localizes to endosomes and regulates phagocytic cup formation in macrophages. mDia1 (and ... Stress fiber formation Endocytosis Microtubule functions Stress fibers are acto-myosin structures, which are important for ...
Most pathogenic variants are missense variants, and have been shown to impair synaptic vesicle endocytosis in a dominant ... Sever S (2003). "Dynamin and endocytosis". Curr. Opin. Cell Biol. 14 (4): 463-7. doi:10.1016/S0955-0674(02)00347-2. PMID ... 1997). "Amphiphysin heterodimers: potential role in clathrin-mediated endocytosis". Mol. Biol. Cell. 8 (10): 2003-15. doi: ... June 2015). "Epileptic encephalopathy-causing mutations in DNM1 impair synaptic vesicle endocytosis". Neurology. Genetics. 1 (1 ...
Sever S (2003). "Dynamin and endocytosis". Curr. Opin. Cell Biol. 14 (4): 463-7. doi:10.1016/S0955-0674(02)00347-2. PMID ... induces tubular membrane invaginations and participates in endocytosis". J. Biol. Chem. 279 (38): 40091-9. doi:10.1074/jbc. ...
PI(3,4)P2 has, however, been shown to play a role in the invagination phase of clathrin-mediated endocytosis. C2α and C2β are ... Posor Y, Eichhorn-Grünig M, Haucke V (June 2015). "Phosphoinositides in endocytosis". Biochimica et Biophysica Acta (BBA) - ...
Sahay, G (2010). "Endocytosis of Nanomedicines". Journal of Controlled Release. 145 (3): 182−195. doi:10.1016/j.jconrel.2010.01 ... Carriers generally gain entry to the cell interior via either Endocytosis (the majority of carriers) or Fusion with the cell's ... Most medically applicable ASOs are naked molecules that are able to enter cells through endocytosis and exert their therapeutic ... Patel, S (2019). "Brief update on endocytosis of nanomedicines". Advanced Drug Delivery Reviews. 144: 90-111. doi:10.1016/j. ...
Qualmann B, Kessels MM (2003). "Endocytosis and the cytoskeleton". Int. Rev. Cytol. International Review of Cytology. 220: 93- ...
The bacterium's ability to synthesize sterols may also be involved in its capacity for membrane invaginations and endocytosis ... This may suggest that Planctomycetota and eukaryote endocytosis mechanism share a common evolutionary origin, that the two ... Fuerst, John A.; Sagulenko, Evgeny (August 2014). "Towards understanding the molecular mechanism of the endocytosis-like ... Jermy, Andrew (August 2010). "Evolution: Bacterial endocytosis uncovered". Nature Reviews Microbiology. 8 (8): 534-535. doi: ...
Sengar AS, Wang W, Bishay J, Cohen S, Egan SE (Mar 1999). "The EH and SH3 domain Ese proteins regulate endocytosis by linking ... Fernández-Chacón R, Achiriloaie M, Janz R, Albanesi JP, Südhof TC (Apr 2000). "SCAMP1 function in endocytosis". The Journal of ... Fernández-Chacón R, Achiriloaie M, Janz R, Albanesi JP, Südhof TC (Apr 2000). "SCAMP1 function in endocytosis". The Journal of ... A protein connection between exocytosis and endocytosis?". The Journal of Biological Chemistry. 274 (26): 18446-54. doi:10.1074 ...
Fernández-Chacón R, Achiriloaie M, Janz R, Albanesi JP, Südhof TC (April 2000). "SCAMP1 function in endocytosis". The Journal ...
Qualmann B, Kessels MM (2003). "Endocytosis and the cytoskeleton". Int. Rev. Cytol. International Review of Cytology. 220: 93- ...
Mellman I (1996). "Endocytosis and molecular sorting". Annual Review of Cell and Developmental Biology. 12: 575-625. doi: ... Molecules can be internalized via receptor-mediated endocytosis in clathrin-coated vesicles. Other types of vesicles also form ... Internalization of these receptors from the plasma membrane occurs by receptor-mediated endocytosis. LDL is released in ... Dautry-Varsat A (March 1986). "Receptor-mediated endocytosis: the intracellular journey of transferrin and its receptor". ...
Fernández-Chacón R, Achiriloaie M, Janz R, Albanesi JP, Südhof TC (April 2000). "SCAMP1 function in endocytosis". J. Biol. Chem ... Fernández-Chacón R, Achiriloaie M, Janz R, Albanesi JP, Südhof TC (2000). "SCAMP1 function in endocytosis". J. Biol. Chem. 275 ...
ISBN 978-1-4729-1130-8. Magnusson S, Kjeken R, Berg T (March 1993). "Characterization of two distinct pathways of endocytosis ... Nichols BJ, Lippincott-Schwartz J (October 2001). "Endocytosis without clathrin coats". Trends Cell Biol. 11 (10): 406-412. doi ...
positive regulation of clathrin coated pit-dependent endocytosis, positive regulation of clathrin-dependent endocytosis, ... Gene Ontology Term: positive regulation of clathrin-dependent endocytosis. GO ID. GO:2000370 Aspect. Biological Process. ... Any process that activates or increases the frequency, rate or extent of clathrin-mediated endocytosis.. Synonyms. ... positive regulation of clathrin-mediated endocytosis View GO Annotations in other species in AmiGO ...
Abstract: Clathrin-mediated endocytosis is a conserved process utilised by metazoans and fungi for the internalisation of cell ... An Electron Microscopy Study into Vps1 and the role of its F-actin Binding Regions within Clathrin-mediated Endocytosis ... An Electron Microscopy Study into Vps1 and the role of its F-actin Binding Regions within Clathrin-mediated Endocytosis. ...
... DSpace/Manakin Repository. ...
Our results show for the first time that sst1 mediates a dynamic process of endocytosis, recycling, and re-endocytosis of its ... Agonist-induced endocytosis of rat somatostatin receptor 1. Endocrinology, 148 (3). pp. 1050-1058. ISSN 1945-7170 ... Cultured Endocytosis/*drug effects Protein Transport/drug effects Rats Receptors, Somatostatin/*agonists/*metabolism ... somatostatin-14 was internalized through a dynamic process of continuous endocytosis, recycling, and recruitment of ...
This domain is present in the epsin or epsin-related (epsinR) adaptor proteins, which are implicated in endocytosis and Golgi- ... In the protozoa parasite Giardia lamblia, endocytosis and lysosomal protein trafficking are vital parasite-specific processes ... The giardial ENTH protein participates in lysosomal protein trafficking and endocytosis. .noexiste{ color: #000; } .imagenItem{ ... clathrin and ubiquitin and was involved in receptor-mediated endocytosis. It also bonded PI4P, the gamma subunit of AP-1 and ...
title = "Synaptojanin and Endophilin Mediate Neck Formation during Ultrafast Endocytosis",. abstract = "Ultrafast endocytosis ... synaptic vesicle endocytosis, synaptic vesicle recycling, synaptojanin, ultrafast endocytosis", ... N2 - Ultrafast endocytosis generates vesicles from the plasma membrane as quickly as 50 ms in hippocampal neurons following ... AB - Ultrafast endocytosis generates vesicles from the plasma membrane as quickly as 50 ms in hippocampal neurons following ...
The endocytosis of Delta is only seen in the mesoderm and requires the activity of the sna and neuralized (neur) genes. ... Snail is required for Delta endocytosis and Notch-dependent activation of single-minded expression. ... Interestingly, the Neur-mediated endocytosis of Delta has recently been shown to be sufficient for the non-autonomous ... dependent repression in a cell non-autonomous fashion by promoting the Neur-dependent endocytosis of Delta in the mesoderm. ...
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... triggers its endocytosis through clathrin-mediated endocytosis (CME). We find that CME of Rh1 is regulated by ... In WT flies, illumination increases Rh1 endocytosis into a Rab5-positive compartment (Han et al., 2007) via CME (Alloway et al ... Phosphatidylinositol 5-phosphate 4-kinase regulates early endosomal dynamics during clathrin-mediated endocytosis Kumari ... Thus, the accurate control of PM membrane turnover through regulation of transport to and endocytosis from the PM is crucial ...
Tagged as: AIDS, endocytosis, hiv, Nef, restriction factor, SERINC, siv, viral, virion, virology, virus, viruses ... Tagged as: endocytosis, hepatitis A virus, Leviviridae, lysosome, mitochondria, mitovirus, Narnaviridae, Narnavirus, quasi- ... Tagged as: dengue virus, endocytosis, flavivirus, glycocalyx, influenza virus, NS1, nuclear import, pathogenesis, quantum dot, ... Tagged as: calicivirus, cryoEM, cytomegalovirus, endocytosis, HCMV, herpesvirus, IFN, isg, m6A methylation, methyl eraser, ...
C F Roff, R Fuchs, I Mellman, A R Robbins; Chinese hamster ovary cell mutants with temperature-sensitive defects in endocytosis ... Chinese hamster ovary cell mutants with temperature-sensitive defects in endocytosis. I. Loss of function on shifting to the ... loss of endocytosis correlated with complete loss of ATP-dependent endosomal acidification in vitro; in the End 2 mutants ... pleiotropic defects in receptor-mediated endocytosis. Activities affected at 41 degrees C include uptake via the D-mannose 6- ...
WNT Activates the AAK1 Kinase to Promote Clathrin-Mediated Endocytosis of LRP6 and Establish a Negative Feedback Loop. ... WNT Activates the AAK1 Kinase to Promote Clathrin-Mediated Endocytosis of LRP6 and Establish a Negative Feedback Loop. Journal ... Signal propagation through a WNT-Frizzled/LRP receptor complex requires proteins necessary for clathrin-mediated endocytosis ( ... and endocytosis of LRP6. We propose that, following WNT receptor activation, increased AAK1 function and CME limits WNT ...
Notably, LRP-1-mediated endocytosis of ADAMTS-5 is impaired in chondrocytes of OA cartilage, with ∼90% reduction in protein ... Here, we report that post-translational endocytosis of ADAMTS-5 by chondrocytes regulates its extracellular activity. We found ... mutagenesis of ADAMTS-5 identified that the noncatalytic first thrombospondin and spacer domains mediate its endocytosis. The ... LRP-1-mediated endocytosis regulates extracellular activity of ADAMTS-5 in articular cartilage. ...
... Front. Biosci. (Landmark Ed) 2017, 22(9 ... Endocytosis is a cellular process mostly responsible for membrane receptor internalization. Cell membrane receptors bind to ... We found that F-BAR protein FCHSD2 (Carom) may facilitate endocytosis via 9 endocytic partners. Carom is highly expressed, ... However, F-BAR protein partners involved in membrane receptor endocytosis and the regulatory mechanism remain unknown. In this ...
Dynamin and endocytosis. / Takei, Kohji.. In: Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme, Vol. 49, No. 7 Suppl, ... Dynamin and endocytosis. In: Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme. 2004 ; Vol. 49, No. 7 Suppl. pp. 938- ... Takei, K 2004, Dynamin and endocytosis, Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme, vol. 49, no. 7 Suppl, pp. ... Takei, K. (2004). Dynamin and endocytosis. Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme, 49(7 Suppl), 938-941. ...
Synaptic vesicle endocytosis was severely impaired during strong exogenous stimulation but resumed efficiently when the ... Thus, dynamin 1-independent mechanisms can support limited synaptic vesicle endocytosis, but dynamin 1 is needed during high ... guanosine triphosphatase thought to be critically required for the fission reaction of synaptic vesicle endocytosis. ... Synaptic vesicle endocytosis was severely impaired during strong exogenous stimulation but resumed efficiently when the ...
The title of this preprint caught my attention, as I am interested in clathrin-mediated endocytosis (CME). In addition to the ... A non-canonical role for dynamin-1 in regulating early stages of clathrin-mediated endocytosis in non-neuronal cells. ... This preprint investigates the roles of dynamin in regulating early stages of clathrin-mediated endocytosis. ...
We have identified an unprecedented role for the ubiquitin-like protein PLIC-2 as a negative regulator of GPCR endocytosis. ... The activity of many signaling receptors is regulated by their endocytosis via clathrin-coated pits (CCPs). For G protein- ... Protein Linking IAP to Cytoskeleton (PLIC)-2 overexpression delayed ligand-induced endocytosis of two GPCRs: the V2 vasopressin ... The closely related isoform PLIC-1 did not affect receptor endocytosis. PLIC-2 specifically inhibited GPCR concentration in ...
Numerous ribosomes are incorporated into both the cytoplasm and nucleus through trypsin-activated endocytosis, which leads to ... Endocytosis inhibition assay. All chemicals used for the inhibition assay are listed in Table S4 and were purchased from Sigma- ... Because the endocytosis inhibitors were cytotoxic, cell viability assays for HDFs were performed using the thiazolyl blue ... S2h). The reduced RICs formation by the endocytosis inhibitor treatments was not due to reduced cell viability because we ...
... 18102014 My TV Shows Collection;. Agatha Christies Poirot COMPLETE S 01-13. Based on Agatha ... hosted by www.1blu.de Wer download Plant Endocytosis 2006 college Schuhschachtel? Wer consumer dem Frosch Quotient Schachtel? ...
Azythomycin, a lysosomotropic antibiotic impairs endocytosis in cultured macrophages. In: Chemistry and Physics of Lipids, Vol ... has distinct effects on fluid-phase and receptor-mediated endocytosis, but does not impair phagocytosis in J774 macrophages. In ...
Endocytosis. */drug effects Endocytosis. */genetics Endocytosis. */physiology Intercellular Signaling Peptides and Proteins*/ ... Endocytosis. * ErbB Receptors*/genetics ErbB Receptors*/metabolism Membrane Proteins*/deficiency Membrane Proteins*/genetics ... endocytosis. . Autorzy: Smith SM; School of Life Sciences, University of Warwick, Coventry, UK.. Smith CJ; School of Life ... Endocytosis. *. Humans ; Microvilli/metabolism ; HeLa Cells ; Cell Membrane/metabolism ; Microscopy, Atomic Force/methods ...
Concept and Meaning of Endocytosis: Endocytosis is called the process by which cells incorporate molecules, ... ... Meaning of Endocytosis. What is Endocytosis:. Endocytosis is called the process by which cells incorporate into them molecules ... Endocytosis and exocytosis. Endocytosis and exocytosis are two different processes. As already explained, endocytosis is the ... The purpose of endocytosis is to regulate the interaction of cells, as well as the composition of lipids and proteins of the ...
Receptor‐mediated endocytosis of human transferrin and its cell surface receptor. J. W. Larrick, C. Enns, A. Raubitschek, H. ... Receptor‐mediated endocytosis of human transferrin and its cell surface receptor. / Larrick, J. W.; Enns, C.; Raubitschek, A. ... Receptor‐mediated endocytosis of human transferrin and its cell surface receptor. In: Journal of Cellular Physiology. 1985 ; ... Larrick, J. W., Enns, C., Raubitschek, A., & Weintraub, H. (1985). Receptor‐mediated endocytosis of human transferrin and its ...
Inactivation of Tor proteins affects the dynamics of endocytic proteins in early stage of endocytosis. Journal of Biosciences. ... Inactivation of Tor proteins affects the dynamics of endocytic proteins in early stage of endocytosis. ... are essentially required for proper endocytic protein dynamics at the early stage of endocytosis. ...
The role of the 100-kDa polypeptide components of clathrin-coated vesicles in endocytosis was investigated by microinjection of ... 100-kDa polypeptides in peripheral clathrin-coated vesicles are required for receptor-mediated endocytosis. *Chin, Daniel J. ... The role of the 100-kDa polypeptide components of clathrin-coated vesicles in endocytosis was investigated by microinjection of ...
Endocytosis: 17.1: Techniques for Studying the Secretory PathwayAssays that follow protein trafficking through a secretory ...
We study endocytosis - the process by which cells absorb substances from outside by engulfing them in a vesicle. Our work ... We study endocytosis - the process by which cells absorb substances from outside by engulfing them in a vesicle. Our work ...
Categorized as Endocytosis 19. 19.95 2.11) (Physique 3(b)). day 14.5 by cervical dislocation, and the spleen and the uterine ... Categorized as Endocytosis Optical sections were documented having a 63/1. Optical sections were documented having a 63/1.4 ... Categorized as Endocytosis Born to perform: control of transcription elongation by RNA polymerase II. Born to perform: ... Categorized as Endocytosis 2011;96:430C7. 2011;96:430C7. the assumption that modifications in serum androgens possess ...
  • Ultrafast endocytosis generates vesicles from the plasma membrane as quickly as 50 ms in hippocampal neurons following synaptic vesicle fusion. (elsevier.com)
  • These data together suggest that synaptojanin and endophilin can mediate membrane remodeling on a millisecond timescale during ultrafast endocytosis. (elsevier.com)
  • demonstrate dual roles for synaptojanin and endophilin in membrane remodeling and clathrin uncoating on rapid timescales during ultrafast endocytosis. (elsevier.com)
  • Endocytosis is a cellular process mostly responsible for membrane receptor internalization. (imrpress.com)
  • We previously proposed that F-BAR protein initiates membrane curvature and mediates endocytosis via its binding partners. (imrpress.com)
  • However, F-BAR protein partners involved in membrane receptor endocytosis and the regulatory mechanism remain unknown. (imrpress.com)
  • We identified 34 endocytic membrane receptors and 10 regulating proteins in clathrin-dependent endocytosis (CDE), a major process of membrane receptor internalization. (imrpress.com)
  • Endocytosis is called the process by which cells incorporate into them molecules, large or small, that are covered by a membrane vesicle. (lifestylemommy.me)
  • The purpose of endocytosis is to regulate the interaction of cells, as well as the composition of lipids and proteins of the plasma membrane. (lifestylemommy.me)
  • Caveolin-mediated endocytosis: these are small invaginations that occur in the plasma membrane and their process is controlled by GTAase signaling complexes. (lifestylemommy.me)
  • As already explained, endocytosis is the process that allows various molecules to be incorporated into cells through membrane vesicles. (lifestylemommy.me)
  • The Euresco/EMBL sponsored meeting on 'Membrane Dynamics in Endocytosis' took place on 6-11 October in Tomar, Portugal. (elsevier.com)
  • Schmid, SL & Sorkin, AD 2002, ' Days and Knights discussing membrane dynamics in endocytosis: Meeting report from the Euresco/EMBL Membrane Dynamics in Endocytosis, 6-11 October in Tomar, Portugal ', Traffic , vol. 3, no. 1, pp. 77-85. (elsevier.com)
  • Plasma Membrane Multiple Choice Questions and Answers (MCQs) , Exocytosis and Endocytosis quiz questions for online MCAT classes. (mcqslearn.com)
  • When vesicles in cytoplasm combines with plasma membrane excreting hormones and other materials out of cell than this process is called' MCQ PDF: exocytosis and endocytosis with choices exocytosis, endocytosis, excretion, and engulfing for online MCAT classes. (mcqslearn.com)
  • The ability of receptor complexes to undergo ligand-mediated endocytosis was evaluated by using membrane fractionation and fluorescence microscopy. (umassmed.edu)
  • The process of endocytosis describes the internalization and subsequent transport of plasma membrane components and extracellular material. (edu.vn)
  • The studies presented in this work focus on identifying novel proteins involved in endocytosis and characterizing their role in membrane trafficking. (edu.vn)
  • Together, these studies have revealed previously unknown roles for proteins in endocytosis that demonstrate the myriad interconnections within membrane trafficking pathways and between processes, such as endocytosis and cell polarity, that are necessary for cell physiology. (edu.vn)
  • Clathrin-mediated endocytosis (CME) is the main route of internalization from the plasma membrane. (rcsb.org)
  • While important little elements, such as amino acids, ions and sugars, can navigate the plasma membrane layer through the actions of membrane layer stations or transporters, macromolecules must end up being transported into cells by endocytosis. (antiviralbiologic.com)
  • 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. (achengula.com)
  • TORC2 has been found to regulate cell polarity, endocytosis, and actin polymerization in response to external stimuli, and studies have shown that the localization of TORC2 to the plasma membrane is essential for the complex's function. (berkeley.edu)
  • Mechanochemical feedback control of dynamin independent endocytosis modulates membrane tension in adherent cells. (ccamp.res.in)
  • The absence of this cluster results in the relocalization of Us9 to the plasma membrane due to a defect in endocytosis. (vetres.org)
  • 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. (vetres.org)
  • The condition seems to be caused by anomalies in the endocytosis of membrane components towards the lysosomes. (cdc.gov)
  • Adaptor protein 2 (AP2), a heterotetrameric complex comprising AP2α, AP2β2, AP2μ2 and AP2σ2 subunits, is ubiquitously expressed and involved in endocytosis and trafficking of membrane proteins, such as the calcium-sensing receptor (CaSR), a G-protein coupled receptor that signals via Gα11. (birmingham.ac.uk)
  • The endocytic pathway consists of phagocytosis, clathrin-mediated endocytosis, caveolae-mediated endocytosis (CvME), lipid-mediated endocytosis, clathrin- and caveolin-independent receptor mediated endocytosis and macropinocytosis (Li et al. (achengula.com)
  • The lysosomes are aimed for the digestion of the macromolecules from phagocytosis, endocytosis, and autophagy. (blurtit.com)
  • We found that GlENTHp (for G. lamblia ENTH protein) localized in the cytosol, strongly interacted with PI3,4,5P3, was associated with the alpha subunit of AP-2, clathrin and ubiquitin and was involved in receptor-mediated endocytosis. (conicet.gov.ar)
  • We have isolated three independent Chinese hamster ovary cell mutants (B3853, I223, and M311) with temperature-sensitive, pleiotropic defects in receptor-mediated endocytosis. (rupress.org)
  • Signal propagation through a WNT-Frizzled/LRP receptor complex requires proteins necessary for clathrin-mediated endocytosis (CME). (duke.edu)
  • In this study, we established database mining strategies to explore mechanisms underlying receptor-related endocytosis. (imrpress.com)
  • We conclude that Carom may mediate receptor endocytosis and transport endocytic receptors to the cytoplasm for receptor signaling and lysosome/proteasome degradation, or to the nucleus for RNA processing, gene transcription and DNA repair. (imrpress.com)
  • The ubiquitin-like protein PLIC-2 is a negative regulator of G protein-coupled receptor endocytosis. (cmu.edu)
  • Protein Linking IAP to Cytoskeleton (PLIC)-2 overexpression delayed ligand-induced endocytosis of two GPCRs: the V2 vasopressin receptor and beta-2 adrenergic receptor, without affecting endocytosis of the transferrin or epidermal growth factor receptor. (cmu.edu)
  • The closely related isoform PLIC-1 did not affect receptor endocytosis. (cmu.edu)
  • Receptor-mediated endocytosis: it is a mechanism by which a set of selected molecules are incorporated into cells. (lifestylemommy.me)
  • We have studied the process of transferrin endocytosis in human erythromyeloid cell line K562 using fluorescein (FL) and rhodamine (RD) labeled iron‐saturated transferrin (FeTF), and a fluorescein labeled monoclonal antibody to the transferrin receptor (FL‐mAB). (elsevier.com)
  • These studies support the concept that a specific trigger is required for transferrin receptor endocytosis. (elsevier.com)
  • 100-kDa polypeptides in peripheral clathrin-coated vesicles are required for receptor-mediated endocytosis. (harvard.edu)
  • Recovery of ethanol-induced impairments in receptor-mediated endocytosis of asialoorosomucoid in isolated rat hepatocytes. (nebraska.edu)
  • Dive into the research topics of 'Recovery of ethanol-induced impairments in receptor-mediated endocytosis of asialoorosomucoid in isolated rat hepatocytes. (nebraska.edu)
  • Endocytosis of the Ang ll-bound receptor not only desensitizes AT1R signaling from the cell surface but also activates specific intracellular signaling pathways. (grantome.com)
  • Clarifying the events that ensue will potentially suggest approaches for novel therapeutics for cardiovascular diseases related to AT1R dysfunction, and will provide new insights into the mechanism underlying receptor endocytosis in general. (grantome.com)
  • Scavenger receptor B1 facilitates the endocytosis of Escherichia coli via TLR4 signaling in mammary gland infection. (bvsalud.org)
  • We further find that giant ankyrin-G promotes GABAergic synapse stability through opposing endocytosis of GABA A receptors, and requires a newly described interaction with GABARAP, a GABA A receptor-associated protein. (elsevier.com)
  • Factor V endocytosis by megakaryocytes is specific, clathrin-dependent, and mediated by a two receptor system. (uvm.edu)
  • We found that F-BAR protein FCHSD2 (Carom) may facilitate endocytosis via 9 endocytic partners. (imrpress.com)
  • SPHK1 is also targeted to physiologically occurring early endocytic intermediates, and is highly enriched in nerve terminals, which are cellular compartments specialized for exo/endocytosis. (ox.ac.uk)
  • IMSEAR at SEARO: Inactivation of Tor proteins affects the dynamics of endocytic proteins in early stage of endocytosis. (who.int)
  • Taken together, both functional Tor proteins, Tor1 and Tor2, are essentially required for proper endocytic protein dynamics at the early stage of endocytosis. (who.int)
  • An in vitro endocytosis assay was adapted for use with yeast cytosol, in order to provide a biochemical method for identifying proteins required for the internalization of coated pits or endocytic vesicles. (edu.vn)
  • Endocytosis utilizes multiple endocytic paths for different types of packages subdivided into clathrin-independent and clathrin-dependent tracks [1]. (antiviralbiologic.com)
  • Abstract: Clathrin-mediated endocytosis is a conserved process utilised by metazoans and fungi for the internalisation of cell surface receptors into vesicles upon ligand binding. (dur.ac.uk)
  • The activity of many signaling receptors is regulated by their endocytosis via clathrin-coated pits (CCPs). (cmu.edu)
  • For G protein-coupled receptors (GPCRs), recruitment of the adaptor protein arrestin to activated receptors is thought to be sufficient to drive GPCR clustering in CCPs and subsequent endocytosis. (cmu.edu)
  • SCARB1 belongs to class B of Scavenger receptors (SRs) that are known to be involved in binding and endocytosis of various pathogens. (bvsalud.org)
  • Another important therapeutic strategy is established on the administration of HMGB1 antagonists precluding RAGE-mediated endocytosis of HMGB1 and HMGB1-bound molecules capable of activating intracellular cognate receptors. (frontiersin.org)
  • Mutant receptors that fail to bind alpha-factor (Ste2-S184R) or lack the endocytosis signal (Ste2-T326) became competent for ligand-mediated endocytosis when they were expressed in cells containing wild-type receptors. (umassmed.edu)
  • We conclude that alpha-factor receptors form homo-oligomers and that these complexes are subject to ligand-mediated endocytosis. (umassmed.edu)
  • Furthermore, we show for the first time that unoccupied receptors participate in these endocytosis-competent complexes. (umassmed.edu)
  • ENDOSOMES play a central role in endocytosis. (bvsalud.org)
  • This preprint investigates the roles of dynamin in regulating early stages of clathrin-mediated endocytosis. (biologists.com)
  • A selective activity-dependent requirement for dynamin 1 in synaptic vesicle endocytosis. (ox.ac.uk)
  • Dynamin 1 is a neuron-specific guanosine triphosphatase thought to be critically required for the fission reaction of synaptic vesicle endocytosis. (ox.ac.uk)
  • Thus, dynamin 1-independent mechanisms can support limited synaptic vesicle endocytosis, but dynamin 1 is needed during high levels of neuronal activity. (ox.ac.uk)
  • Synaptic vesicle endocytosis was severely impaired during strong exogenous stimulation but resumed efficiently when the stimulus was terminated. (ox.ac.uk)
  • Independently inhibiting clathrin-and caveolae-mediated endocytosis, as well as macropinocytosis significantly decreased intracellular delivery of 4.4-to 500-kDa dextrans. (rug.nl)
  • This domain is present in the epsin or epsin-related (epsinR) adaptor proteins, which are implicated in endocytosis and Golgi-to-endosome protein trafficking, respectively, in other eukaryotic cells. (conicet.gov.ar)
  • Exocytosis and Endocytosis Multiple Choice Questions (MCQ), Exocytosis and Endocytosis quiz answers PDF to study mcat biology online course for mcat biology classes. (mcqslearn.com)
  • Exocytosis and Endocytosis ' Book PDF: passive transport, composition of membranes, exocytosis and endocytosis, membranes structure test prep for online assessment test for jobs. (mcqslearn.com)
  • Study exocytosis and endocytosis quiz questions for merit scholarship test and certificate programs for best MCAT tutors. (mcqslearn.com)
  • In the protozoa parasite Giardia lamblia, endocytosis and lysosomal protein trafficking are vital parasite-specific processes that involve the action of the adaptor complexes AP-1 and AP-2 and clathrin. (conicet.gov.ar)
  • Notably, LRP-1-mediated endocytosis of ADAMTS-5 is impaired in chondrocytes of OA cartilage, with ∼90% reduction in protein levels of LRP-1 without changes in its mRNA levels. (ox.ac.uk)
  • We have identified an unprecedented role for the ubiquitin-like protein PLIC-2 as a negative regulator of GPCR endocytosis. (cmu.edu)
  • Endocytosis requires the coordinated activity of many protein factors, and the specific mechanisms employed by the cell for internalization remain only partially understood. (edu.vn)
  • Ribosomes were incorporated into cells through trypsin-activated endocytosis and generated cell clusters that were similar to embryoid bodies. (nature.com)
  • Clathrin-mediated endocytosis: It is generated in all mammalian cells. (lifestylemommy.me)
  • We study endocytosis - the process by which cells absorb substances from outside by engulfing them in a vesicle. (zeriallab.org)
  • Knockdown also affected the endocytosis of E.coli in GMECs demonstrating that E.coli uses SCARB1 function to gain entry in cells . (bvsalud.org)
  • 100-fold higher than plasma factor The entire platelet-derived factor Va pool originates via endocytosis of the procofactor, factor V, from plasma by megakaryocytes, the platelet precursor cells. (uvm.edu)
  • One of the vital steps in both types of cells is the process of endocytosis. (cuni.cz)
  • Expression of phosphatidylserine on live tumor cells mediated their recognition and endocytosis by DC resulting in the presentation of tumor antigens to antigen-specific T cells. (cdc.gov)
  • The different pathways of endocytosis share an initial step involving local back to the inside curvature of the cells lipid bilayer. (antiviralbiologic.com)
  • Nevertheless, the different paths of endocytosis talk about an preliminary stage regarding regional back to the inside curvature transformation of the cells lipid bilayer [2]. (antiviralbiologic.com)
  • On the basis of our longitudinal study, this surface reaction appears to peak at approximately 10 days after trauma and may indicate that the inner sulcus cells are extremely active in the endocytosis of cellular debris. (cdc.gov)
  • The great diversity in actin network architectures and dynamics is exploited by cells to drive fundamental biological processes, including cell migration, endocytosis, and cell division. (jbc.org)
  • A specialized tyrosine-based endocytosis signal in MR1 controls antigen presentation to MAIT cells. (technologynetworks.com)
  • Our results show for the first time that sst1 mediates a dynamic process of endocytosis, recycling, and re-endocytosis of its cognate ligand. (reading.ac.uk)
  • The role of the 100-kDa polypeptide components of clathrin-coated vesicles in endocytosis was investigated by microinjection of specific monoclonal antibodies. (harvard.edu)
  • The existence of clathrin- and caveolin-independent forms of endocytosis raises the relevant question of how these vesicles are actually formed. (antiviralbiologic.com)
  • In conclusion, these data demonstrate that endocytosis is a key mechanism in UMTD besides transient pore formation, with the contribution of endocytosis being dependent on molecular size. (rug.nl)
  • Since endocytosis and postendocytic endosomal trafficking are implicated in many physiologically important processes in neurons (e.g., axon outgrowth) as well as in disease, we need to understand how the neuron-specific machinery impinges on and interfaces with ubiquitously expressed endosomal regulators. (jneurosci.org)
  • LRP-1-mediated endocytosis regulates extracellular activity of ADAMTS-5 in articular cartilage. (ox.ac.uk)
  • Here, we report that post-translational endocytosis of ADAMTS-5 by chondrocytes regulates its extracellular activity. (ox.ac.uk)
  • Depletion of cellular PLIC-2 accelerated GPCR endocytosis, confirming its regulatory function at endogenous levels. (cmu.edu)
  • The endocytosis process is also necessary to give immune responses, for the development of intercellular communication and for the exchange of cellular signals to take place. (lifestylemommy.me)
  • In addition to triggering endocytosis, UMTD also evoked transient pore formation, as demonstrated by the influx of calcium ions and cellular release of preloaded dextrans after US and microbubble exposure. (rug.nl)
  • Importantly, their mutual interaction is required for many EGFR-mediated cellular functions including proliferation, migration, survival and EGFR endocytosis. (imrpress.com)
  • Because the number of cell surface binding sites did not change during prolonged stimulation, somatostatin-14 was internalized through a dynamic process of continuous endocytosis, recycling, and recruitment of intracellularly present sst1-HSV. (reading.ac.uk)
  • In this model, Sna cell-autonomously represses sim expression in the mesoderm and relieves Su(H)-dependent repression in a cell non-autonomous fashion by promoting the Neur-dependent endocytosis of Delta in the mesoderm. (pasteur.fr)
  • Chinese hamster ovary cell mutants with temperature-sensitive defects in endocytosis. (rupress.org)
  • Numerous ribosomes are incorporated into both the cytoplasm and nucleus through trypsin-activated endocytosis, which leads to cell-cluster formation. (nature.com)
  • First, the toxin enters the cell by way of endocytosis, through a coated pit on the cell's surface. (cdc.gov)
  • They do things like break down bacteria through a process called endocytosis, or cell eating. (chewdigest.com)
  • We used a combination of apoptosis assays, cell cycle assays, tissue distribution studies, cell endocytosis, transwell invasion assays, and immunoblotting to evaluate the characteristics of [email protected] as a drug delivery system. (ejbiotechnology.cl)
  • Together, these data indicated uptake of molecules via endocytosis after UMTD. (rug.nl)
  • Involvement of endocytosis in uptake of phosphatidylserine-coated single-walled cargon nanotubes by RAW 264.7 macrophages. (cdc.gov)
  • The hypothesis of this proposal, based on our published work and preliminary evidence, is that PLD2-generated PA plays a central signaling role in regulation of AT1R endocytosis and signaling. (grantome.com)
  • That is called pinocytosis, sometimes called fluid-endocytosis. (chewdigest.com)
  • Interestingly, the Neur-mediated endocytosis of Delta has recently been shown to be sufficient for the non-autonomous activation of Notch target genes in wing imaginal discs. (pasteur.fr)
  • Impact of Multiple Sclerosis Risk Polymorphism rs7665090 on MANBA Activity, Lysosomal Endocytosis, and Lymphocyte Activation. (cdc.gov)
  • In this work, nematode Caenorhabditis elegans was used as a model organism to characterize new regulator of the Wnt signalling pathway which acts at the level of endocytosis. (cuni.cz)
  • transcription cleaves an abundant endocytosis rate learned on the transport of grayed forces. (erik-mill.de)
  • In specific aim 1, we will test the hypothesis that PLD2 facilitates AT1R endocytosis by regulating spatiotemporal dynamics of phosphatidylinositol 4,5-bisphosphate {PI(4,5)P2}, which is an essential phospholipid in endocytosis. (grantome.com)
  • Viral mutants lacking the highly conserved Us9 acidic motif required for endocytosis and trans -Golgi network targeting are defective for directional spread in the rat visual system. (vetres.org)
  • We hypothesized that endocytosis and pore formation are involved during US and microbubble targeted delivery (UMTD) of therapeutic compounds. (rug.nl)
  • We also have investigated the role of a dileucine endocytosis signal in the Us9 cytoplasmic tail in the recycling and retention of Us9 to the TGN region. (vetres.org)
  • Coupling between endocytosis and sphingosine kinase 1 recruitment. (ox.ac.uk)
  • Here we demonstrate that synaptojanin-1, and its partner endophilin-A, function in ultrafast endocytosis. (elsevier.com)
  • The endocytosis of Delta is only seen in the mesoderm and requires the activity of the sna and neuralized (neur) genes. (pasteur.fr)
  • Bearded family members inhibit Neuralized-mediated endocytosis and signaling activity of Delta in Drosophila. (semanticscholar.org)
  • This differential interaction may underlie PLIC-2 specific effect on GPCR endocytosis. (cmu.edu)