|
Vesicle-associated Membrane Protein
Vesicle associated membrane proteins (VAMP) are a family of SNARE proteins with similar structure, and are mostly involved in vesicle fusion. * VAMP1 and VAMP2 proteins known as synaptobrevins are expressed in brain and are constituents of the synaptic vesicles, where they participate in neurotransmitter release. * VAMP3 (known as cellubrevin) is ubiquitously expressed and participates in regulated and constitutive exocytosis as a constituent of secretory granules and secretory vesicles. * VAMP5 and VAMP7 ( SYBL1) participate in constitutive exocytosis. ** VAMP5 is a constituent of secretory vesicles, myotubes and tubulovesicular structures. ** VAMP7 is found both in secretory granules and endosomes. * VAMP8 (known as endobrevin) participates in endocytosis and is found in early endosomes. VAMP8 also participates the regulated exocytosis in pancreatic acinar cells. *VAMP4 Vesicle-associated membrane protein 4 is a protein that in humans is encoded by the ''VAMP4'' gene. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SNARE (protein)
SNARE proteins – " SNAP REceptor" – are a large protein family consisting of at least 24 members in yeasts, more than 60 members in mammalian cells, and some numbers in plants. The primary role of SNARE proteins is to mediate vesicle fusion – the fusion of vesicles with the target membrane; this notably mediates exocytosis, but can also mediate the fusion of vesicles with membrane-bound compartments (such as a lysosome). The best studied SNAREs are those that mediate the neurotransmitter release of synaptic vesicles in neurons. These neuronal SNAREs are the targets of the neurotoxins responsible for botulism and tetanus produced by certain bacteria. Types SNAREs can be divided into two categories: ''vesicle'' or ''v-SNAREs'', which are incorporated into the membranes of transport vesicles during budding, and ''target'' or ''t-SNAREs'', which are associated with nerve terminal membranes. Evidence suggests that t-SNAREs form stable subcomplexes which serve as guides f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vesicle Fusion
Vesicle fusion is the merging of a vesicle with other vesicles or a part of a cell membrane. In the latter case, it is the end stage of secretion from secretory vesicles, where their contents are expelled from the cell through exocytosis. Vesicles can also fuse with other target cell compartments, such as a lysosome. Exocytosis occurs when secretory vesicles transiently dock and fuse at the base of cup-shaped structures at the cell plasma membrane called porosome, the universal secretory machinery in cells. Vesicle fusion may depend on SNARE proteins in the presence of increased intracellular calcium (Ca2+) concentration. Triggers Stimuli that trigger vesicle fusion act by increasing intracellular Ca2+. * Synaptic vesicles commit vesicle fusion by a nerve impulse reaching the synapse, activating voltage-dependent calcium channels that cause influx of Ca2+ into the cell. * In the endocrine system, many hormones are released by their releasing hormones binding to G protein coupled rec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VAMP1
Vesicle-associated membrane protein 1 (VAMP1) is a protein that in humans is encoded by the ''VAMP1'' gene. Function Synaptobrevins/VAMPs, syntaxins, and the 25-kD synaptosomal-associated protein SNAP25 are the main components of a protein complex involved in the docking and/or fusion of synaptic vesicles with the presynaptic membrane. VAMP1 is a member of the vesicle-associated membrane protein (VAMP)/synaptobrevin family. Multiple alternative splice variants that encode proteins with alternative carboxy ends have been described, but the full-length nature of some variants has not been defined. Clinical significance Homozygous mutations in VAMP1 have been identified in a series of children affected with a form of congenital myasthenic syndrome and similar presynaptic features in these patients and the knock-out A knockout (abbreviated to KO or K.O.) is a fight-ending, winning criterion in several full-contact combat sports, such as boxing, kickboxing, muay thai, mix ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VAMP2
Vesicle-associated membrane protein 2 (VAMP2) is a protein that in humans is encoded by the ''VAMP2'' gene. Function Synaptobrevins/VAMPs, syntaxins, and the 25-kD synaptosomal-associated protein SNAP25 are the main components of a protein complex involved in the docking and/or fusion of synaptic vesicles with the presynaptic membrane. VAMP2 is a member of the vesicle-associated membrane protein (VAMP)/synaptobrevin family. VAMP2 is thought to participate in neurotransmitter release at a step between docking and fusion. Mice lacking functional synaptobrevin2/VAMP2 gene cannot survive after birth, and have a dramatically reduced synaptic transmission, around 10% of control. The protein forms a stable complex with syntaxin, synaptosomal-associated protein, 25 kD, and complexin. It also forms a distinct complex with synaptophysin. Clinical significance Heterozygous mutations in VAMP2 cause a neurodevelopmental disorder with hypotonia and autistic features (with or without ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synaptobrevin
Synaptobrevins (''synaptobrevin isotypes 1-2'') are small integral membrane proteins of secretory vesicles with molecular weight of 18 kilodalton (kDa) that are part of the vesicle-associated membrane protein (VAMP) family. Synaptobrevin is one of the SNARE proteins involved in formation of the SNARE complexes. Structure Out of four α-helices of the core SNARE complex one is contributed by synaptobrevin, one by syntaxin, and two by SNAP-25 (in neurons). Function SNARE proteins are the key components of the molecular machinery that drives fusion of membranes in exocytosis. Their function however is subject to fine-tuning by various regulatory proteins collectively referred to as ''SNARE masters''. Classification In the Q/R nomenclature for organizing SNARE proteins, VAMP/synaptobrevin family members are classified as R-SNAREs, so named for the presence of an arginine at a specific location within the primary sequence of the protein (as opposed to the SNAREs of the ta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exocytosis
Exocytosis () is a form of active transport and bulk transport in which a cell transports molecules (e.g., neurotransmitters and proteins) out of the cell ('' exo-'' + ''cytosis''). As an active transport mechanism, exocytosis requires the use of energy to transport material. Exocytosis and its counterpart, endocytosis, are used by all cells because most chemical substances important to them are large polar molecules that cannot pass through the hydrophobic portion of the cell membrane by passive means. Exocytosis is the process by which a large amount of molecules are released; thus it is a form of bulk transport. Exocytosis occurs via secretory portals at the cell plasma membrane called porosomes. Porosomes are permanent cup-shaped lipoprotein structure at the cell plasma membrane, where secretory vesicles transiently dock and fuse to release intra-vesicular contents from the cell. In exocytosis, membrane-bound secretory vesicles are carried to the cell membrane, where they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VAMP3
Vesicle-associated membrane protein 3 is a protein that in humans is encoded by the ''VAMP3'' gene. Function Synaptobrevins/VAMPs, syntaxins, and the 25-kD synaptosomal-associated protein are the main components of a protein complex involved in the docking and/or fusion of synaptic vesicles with the presynaptic membrane. This gene is a member of the vesicle-associated membrane protein (VAMP)/synaptobrevin family. Because of its high homology to other known VAMPs, its broad tissue distribution, and its subcellular localization, the protein encoded by this gene was shown to be the human equivalent of the rodent cellubrevin. In platelets the protein resides on a compartment that is not mobilized to the plasma membrane on calcium or thrombin stimulation. Interactions VAMP3 has been shown to interact with * BCAP31, * BVES, * SNAP23, * STX4, * STX6 Syntaxin-6 is a protein that in humans is encoded by the ''STX6'' gene. Interactions STX6 has been shown to interact with SNAP2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VAMP5
''Vesicle-associated membrane protein 5'' also known as ''VAMP5'' is a human gene which encodes a member of the synaptobrevin protein family. Function VAMPs (synaptobrevins) along with syntaxins and the 25-kD synaptosomal-associated protein are the main components of a protein complex involved in the docking and/or fusion of vesicles and cell membranes. The VAMP5 gene is a member of the vesicle-associated membrane protein (VAMP)/synaptobrevin family and the SNARE superfamily. This VAMP family member may participate in vesicle trafficking events that are associated with myogenesis Myogenesis is the formation of skeletal muscular tissue, particularly during embryonic development. Muscle fibers generally form through the fusion of precursor myoblasts into multinucleated fibers called ''myotubes''. In the early development o .... References External links * {{gene-2-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SYBL1
Synaptobrevin-like protein 1 (SYBL1), also known as vesicle-associated membrane protein 7 (VAMP7), is a protein that in humans is encoded by the ''VAMP7'', or ''SYBL1'', gene. Function SYBL1 is a transmembrane protein that is a member of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) family. SYBL1 localizes to late endosomes and lysosomes and is involved in the fusion of transport vesicles to their target membranes. Interactions SYBL1 has been shown to interact with SNAP23 and AP3D1 AP-3 complex subunit delta-1 is a protein that in humans is encoded by the ''AP3D1'' gene. Function AP3D1 is a subunit of the AP3 adaptor-like complex, which is not associated with clathrin. The AP3D1 subunit is implicated in intracellular bio .... References Further reading * * * * * * * * * * * * * * * * * External links * {{gene-X-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VAMP8
Vesicle-associated membrane protein 8 is a protein that in humans is encoded by the ''VAMP8'' gene. Synaptobrevins/VAMPs, syntaxins, and the 25-kD synaptosomal-associated protein SNAP25 are the main components of a protein complex involved in the docking and/or fusion of synaptic vesicles with the presynaptic membrane. The protein encoded by this gene is a member of the vesicle-associated membrane protein (VAMP)/synaptobrevin family. It is associated with the perinuclear vesicular structures of the early endocytic compartment. It has been found that VAMP8 interacts specifically with the soluble NSF-attachment protein (alpha-SNAP), most likely through an VAMP8-containing SNARE complex. Phosphorylation of VAMP8 inside the conserved SNARE-domain can suppress vesicle fusion. Interactions Vesicle-associated membrane protein 8 has been shown to interact with STX4, SNAP23, STX1A Syntaxin-1A is a protein that in humans is encoded by the ''STX1A'' gene. Function Synaptic vesicles stor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endocytosis
Endocytosis is a cellular process in which substances are brought into the cell. The material to be internalized is surrounded by an area of cell membrane, which then buds off inside the cell to form a vesicle containing the ingested material. Endocytosis includes pinocytosis (cell drinking) and phagocytosis (cell eating). It is a form of active transport. History The term was proposed by De Duve in 1963. Phagocytosis was discovered by Élie Metchnikoff in 1882. Pathways Endocytosis pathways can be subdivided into four categories: namely, receptor-mediated endocytosis (also known as clathrin-mediated endocytosis), caveolae, pinocytosis, and phagocytosis Phagocytosis () is the process by which a cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis is .... *Clathrin-mediated endocytosis is mediated by the production of smal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
