title: SNAP-29 is a promiscuous syntaxin-binding SNARE.
abstract: SNARE proteins are key regulators of membrane fusion and are proposed to dictate the specificity with which particular vesicles fuse with particular target organelles. On intracellular organelles that serve as targets for transport vesicles, organelle-specific syntaxins form heterodimers with either SNAP-23 or its recently described homolog SNAP-29. We have performed a variety of in vitro and in vivo binding assays in an attempt to determine whether SNAP-23 and SNAP-29 differ in their ability to form binary SNARE complexes with different intracellular syntaxins. While SNAP-23 preferentially binds to plasma membrane-localized syntaxins, SNAP-29 binds to both plasma membrane and intracellular syntaxins equally well. Furthermore, binding to SNAP-29 augments the ability of syntaxin to bind to vesicle-associated SNAREs and the presence of vesicle SNAREs dramatically increases SNAP-29 binding to syntaxin. These data suggest that SNAP-23 preferentially regulates plasma membrane-vesicle fusion events while SNAP-29 plays a role in the maintenance of various intracellular protein trafficking pathways.
authors.affiliation: Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 2089, USA.
authors.forename: A C
authors.initials: AC
authors.lastname: Hohenstein
authors.forename: P A
authors.initials: PA
authors.lastname: Roche
mesh_terms: D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular; D006056:Golgi Apparatus / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; D050683:R-SNARE Proteins; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D050600:SNARE Proteins; D014162:Transfection; D033921:Vesicular Transport Proteins
chemical_list: D002352:Carrier Proteins; 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; D011994:Recombinant Proteins; C100493:SNAP23 protein, human; C432420:SNAP29 protein, human; D050600:SNARE Proteins; D033921:Vesicular Transport Proteins