Identification of a novel syntaxin- and synaptobrevin/VAMP-binding protein, SNAP-23, expressed in non-neuronal tissues.
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 (synaptosome-associated 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.
Ravichandran
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Experimental Immunology Branch, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA.
Chawla
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A
Roche
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PA
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D015870:Gene Expression; D006801:Humans; D066298:In Vitro Techniques; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; D050683:R-SNARE Proteins; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; D050825:Synaptosomal-Associated Protein 25; D033921:Vesicular Transport Proteins
D002352:Carrier Proteins; D018076:DNA, Complementary; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; D050683:R-SNARE Proteins; D011993:Recombinant Fusion Proteins; C100493:SNAP23 protein, human; C494208:SNAP25 protein, human; C107017:Snap23 protein, mouse; C494209:Snap25 protein, mouse; C494210:Snap25 protein, rat; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; D050825:Synaptosomal-Associated Protein 25; D033921:Vesicular Transport Proteins