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.
Pubmed ID: 8663154 RIS Download
Amino Acid Sequence | Animals | Base Sequence | Carrier Proteins | Cloning, Molecular | DNA, Complementary | Gene Expression | Humans | In Vitro Techniques | Membrane Proteins | Mice | Molecular Sequence Data | Nerve Tissue Proteins | Protein Binding | Qa-SNARE Proteins | Qb-SNARE Proteins | Qc-SNARE Proteins | R-SNARE Proteins | Rats | Recombinant Fusion Proteins | Sequence Homology, Amino Acid | Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins | Synaptosomal-Associated Protein 25 | Vesicular Transport Proteins