2nps | pdb_00002nps
Crystal Structure of the Early Endosomal SNARE Complex
Structural highlights
Function[STX6_HUMAN] Involved in intracellular vesicle trafficking. [VAMP4_MOUSE] Involved in the pathway that functions to remove an inhibitor (probably synaptotagmin-4) of calcium-triggered exocytosis during the maturation of secretory granules. May be a marker for this sorting pathway that is critical for remodeling the secretory response of granule (By similarity). [VTI1A_RAT] V-SNARE that mediates vesicle transport pathways through interactions with t-SNAREs on the target membrane. These interactions are proposed to mediate aspects of the specificity of vesicle trafficking and to promote fusion of the lipid bilayers. Involved in vesicular transport from the late endosomes to the trans-Golgi network. Along with VAMP7, involved in an non-conventional RAB1-dependent traffic route to the cell surface used by KCNIP1 and KCND2 (By similarity). May be concerned with increased secretion of cytokines associated with cellular senescence.[1] [STX12_RAT] SNARE that acts to regulate protein transport between endosomes and the trans-Golgi network (By similarity). The SNARE complex containing STX6, STX12, VAMP4 and VTI1A mediates vesicle fusion (in vitro).[2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedSNARE proteins mediate membrane fusion in eukaryotic cells. They contain conserved SNARE motifs that are usually located adjacent to a C-terminal transmembrane domain. SNARE motifs spontaneously assemble into four helix bundles, with each helix belonging to a different subfamily. Liposomes containing SNAREs spontaneously fuse with each other, but it is debated how the SNAREs are distributed between the membranes. Here, we report that the SNAREs mediating homotypic fusion of early endosomes fuse liposomes in five out of seven possible combinations, in contrast to previously studied SNAREs involved in heterotypic fusion events. The crystal structure of the early endosomal SNARE complex resembles that of the neuronal and late endosomal complexes, but differs in surface side-chain interactions. We conclude that homotypic fusion reactions may proceed with multiple SNARE topologies, suggesting that the conserved SNARE structure allows for flexibility in the initial interactions needed for fusion. Early endosomal SNAREs form a structurally conserved SNARE complex and fuse liposomes with multiple topologies.,Zwilling D, Cypionka A, Pohl WH, Fasshauer D, Walla PJ, Wahl MC, Jahn R EMBO J. 2007 Jan 10;26(1):9-18. Epub 2006 Dec 7. PMID:17159904[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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