Vesicle fusion from yeast to man

Ferro‐Novick, Susan; Jahn, Reinhard

doi:10.1038/370191a0

Cited by 619 publications

(408 citation statements)

References 52 publications

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“…In addition, homologs of these molecules have been found in yeast, and deletion of the yeast VAMP, syntaxin, or SNAP-25 homologs leads to severe defects in protein secretion (reviewed in Ref. 9).…”

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confidence: 99%

Identification of a Novel Syntaxin- and Synaptobrevin/VAMP-binding Protein, SNAP-23, Expressed in Non-neuronal Tissues

Ravichandran

Chawla

Roche

1996

Journal of Biological Chemistry

326

286

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The specificity of vesicular transport is regulated, in part, by the interaction of a vesicle-associated membrane protein termed synaptobrevin/VAMP with a target compartment membrane protein termed syntaxin. These proteins, together with SNAP-25 (synaptosomeassociated protein of 25 kDa), form a complex which serves as a binding site for the general membrane fusion machinery. Synaptobrevin/VAMP and syntaxin are ubiquitously expressed proteins and are believed to be involved in vesicular transport in most (if not all) cells. However, SNAP-25 is present almost exclusively in the brain, suggesting that a ubiquitously expressed homolog of SNAP-25 exists to facilitate transport vesicle/target membrane fusion in other tissues. Using the yeast two-hybrid system, we have identified a 23-kDa protein from human B lymphocytes (termed SNAP-23) that binds tightly to multiple syntaxins and synaptobrevins/ VAMPs in vitro. SNAP-23 is 59% identical with SNAP-25. Unlike SNAP-25, SNAP-23 was expressed in all tissues examined. These findings suggest that SNAP-23 is an essential component of the high affinity receptor for the general membrane fusion machinery and an important regulator of transport vesicle docking and fusion in all mammalian cells.A fundamental goal of cell biology is the elucidation of the molecular steps involved in intracellular protein transport. In general, this process involves the liberation of cargo-containing transport vesicles from "donor" membranes and the subsequent docking and fusion of these vesicles with target, or "acceptor" membranes (1). It is clear that vesicle docking and vesicle fusion are distinct processes mediated by distinct proteins (reviewed in Refs. 2 and 3). Since the general membrane fusion machinery (consisting of NSF 1 and SNAPs) nonspecifically catalyzes membrane fusion, the regulation of fusion between transport vesicles and specific acceptor membranes is thought to lie in the vesicle docking process. In the brain, synaptic vesicle docking is regulated in part by specific interactions of the synaptic vesicle protein synaptobrevin (also known as vesicle-associated membrane protein or VAMP) with the presynaptic plasma membrane-associated proteins syntaxin and SNAP-25 (synaptosome-associated protein of 25 kDa; not related to the SNAPs for NSF). Together these molecules form a stable complex which also functions as a SNAP receptor ("SNARE"). It is believed SNAPs and NSF bind to the SNARE complex at the transport vesicle/target membrane interface so that following vesicle docking membrane fusion can occur.A general model of protein transport in all cells, the SNARE hypothesis, proposes that the specificity of a particular transport step is regulated by the specific interaction of distinct VAMPs and syntaxins on transport vesicles and target (acceptor) membranes, respectively (4). There is considerable experimental evidence to support the SNARE hypothesis, including the demonstration that (a) different isoforms of syntaxin and VAMP exist, some of which can be localized to unique intracellu...

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mentioning

confidence: 99%

Identification of a Novel Syntaxin- and Synaptobrevin/VAMP-binding Protein, SNAP-23, Expressed in Non-neuronal Tissues

Ravichandran

Chawla

Roche

1996

Journal of Biological Chemistry

326

286

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“…SNAP-25 does not contain a transmembrane domain but carries palmitoyl side chains attached to cysteine residues in the middle of the sequence (3, 4). Homologues of these proteins have been identified in many eukaryotic cells including yeast, suggesting that fusion of trafficking vesicles with their respective target membranes is mediated by a conserved mechanism (2,(5)(6)(7)(8).…”

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confidence: 99%

Structural Changes Are Associated with Soluble N-Ethylmaleimide-sensitive Fusion Protein Attachment Protein Receptor Complex Formation

Fasshauer

Otto

Eliason

et al. 1997

Journal of Biological Chemistry

Self Cite

342

372

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SNAP-25, syntaxin, and synaptobrevin play a key role in the regulated exocytosis of synaptic vesicles, but their mechanism of action is not understood. In vitro, the proteins spontaneously assemble into a ternary complex that can be dissociated by the ATPase N-ethylmaleimide-sensitive fusion protein and the cofactors ␣-, ␤-, and ␥-SNAP. Since the structural changes associated with these reactions probably form the basis of membrane fusion, we have embarked on biophysical studies aimed at elucidating such changes in vitro using recombinant proteins. All proteins were purified in a monomeric form. Syntaxin showed significant ␣-helicity, whereas SNAP-25 and synaptobrevin exhibited characteristics of largely unstructured proteins. Formation of the ternary complex induced dramatic increases in ␣-helicity and in thermal stability. This suggests that structure is induced in SNAP-25 and synaptobrevin upon complex formation. In addition, the stoichiometry changed from 2:1 in the syntaxin-SNAP-25 complex to 1:1:1 in the ternary complex. We propose that the transition from largely unstructured monomers to a tightly packed, energetically favored ternary complex connecting two membranes is a key step in overcoming energy barriers for membrane fusion.Neurons release their neurotransmitters by the Ca 2ϩ -dependent exocytosis of synaptic vesicles. In recent years, several membrane proteins have been identified which are required for exocytotic membrane fusion. These proteins include the synaptic vesicle protein synaptobrevin (also referred to as VAMP) 1 and the synaptic membrane proteins syntaxin and SNAP-25, collectively referred to as SNAREs. Synaptobrevin and syntaxin both contain a single transmembrane domain at the C terminus (1, 2). SNAP-25 does not contain a transmembrane domain but carries palmitoyl side chains attached to cysteine residues in the middle of the sequence (3, 4). Homologues of these proteins have been identified in many eukaryotic cells including yeast, suggesting that fusion of trafficking vesicles with their respective target membranes is mediated by a conserved mechanism (2,(5)(6)(7)(8).While the evidence linking synaptobrevin, SNAP-25, and syntaxin to exocytosis is compelling, their precise role is unknown. In detergent extracts of brain membranes, the three proteins form a tight complex (9, 10). A ternary complex with properties similar to the native complex can be formed using recombinant proteins lacking their transmembrane anchors (11). Both native and recombinant complexes can be disassembled by the concerted action of the ATPase NSF and the protein ␣-SNAP (9, 10, 12, 13). The latter two proteins are soluble, abundant, and highly conserved through evolution. They are essential for the fusion of trafficking vesicles with their target membranes (9, 10).The assembly and disassembly of the SNARE proteins has not yet been integrated into a coherent picture of exocytosis. However, any interference with these reactions seriously inhibits membrane fusion (6 -8). To further understand these essential reac...

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“…During exocytosis, the secretory vesicles are directed from donor membranes to target membranes. In yeast, this process is mediated in part by membrane-associated proteins called SNAREs, which are encoded by the SNC genes [65][66][67]. The disruption of genes encoding the SNARE proteins can be detrimental to the organism or even lethal [68,69].…”

Section: Sphingolipids In Endocytosis and Exocytosismentioning

confidence: 99%

Sphingolipids and membrane biology as determined from genetic models

Rao

Acharya

2008

Prostaglandins & Other Lipid Mediators

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The importance of sphingolipids in membrane biology was appreciated early in the twentieth century when several human inborn errors of metabolism were linked to defects in sphingolipid degradation. The past two decades have seen an explosion of information linking sphingolipids with cellular processes. Studies have unraveled mechanistic details of the sphingolipid metabolic pathways, and these findings are being exploited in the development of novel therapies, some now in clinical trials. Pioneering work in yeast has laid the foundation for identifying genes encoding the enzymes of the pathways. The advent of the era of genomics and bioinformatics has led to the identification of homologous genes in other species and the subsequent creation of animal knock-out lines for these genes. Discoveries from these efforts have re-kindled interest in the role of sphingolipids in membrane biology. This review highlights some of the recent advances in understanding sphingolipids' roles in membrane biology as determined from genetic models.

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Vesicle fusion from yeast to man

Cited by 619 publications

References 52 publications

Identification of a Novel Syntaxin- and Synaptobrevin/VAMP-binding Protein, SNAP-23, Expressed in Non-neuronal Tissues

Identification of a Novel Syntaxin- and Synaptobrevin/VAMP-binding Protein, SNAP-23, Expressed in Non-neuronal Tissues

Structural Changes Are Associated with Soluble N-Ethylmaleimide-sensitive Fusion Protein Attachment Protein Receptor Complex Formation

Sphingolipids and membrane biology as determined from genetic models

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