3rk3
From Proteopedia
Truncated SNARE complex with complexin
Structural highlights
Function[SNP25_HUMAN] t-SNARE involved in the molecular regulation of neurotransmitter release. May play an important role in the synaptic function of specific neuronal systems. Associates with proteins involved in vesicle docking and membrane fusion. Regulates plasma membrane recycling through its interaction with CENPF. [VAMP2_HUMAN] Involved in the targeting and/or fusion of transport vesicles to their target membrane. [STX1A_RAT] Potentially involved in docking of synaptic vesicles at presynaptic active zones. May play a critical role in neurotransmitter exocytosis. May mediate Ca(2+)-regulation of exocytosis acrosomal reaction in sperm. [CPLX1_HUMAN] Positively regulates a late step in synaptic vesicle exocytosis. Organizes the SNAREs into a cross-linked zigzag topology that, when interposed between the vesicle and plasma membranes, is incompatible with fusion, thereby preventing SNAREs from releasing neurotransmitters until an action potential arrives at the synapse. Also involved in glucose-induced secretion of insulin by pancreatic beta-cells (By similarity). Publication Abstract from PubMedComplexin prevents SNAREs from releasing neurotransmitters until an action potential arrives at the synapse. To understand the mechanism for this inhibition, we determined the structure of complexin bound to a mimetic of a prefusion SNAREpin lacking the portion of the v-SNARE that zippers last to trigger fusion. The 'central helix' of complexin is anchored to one SNARE complex, while its 'accessory helix' extends away at ~45 degrees and bridges to a second complex, occupying the vacant v-SNARE binding site to inhibit fusion. We expected the accessory helix to compete with the v-SNARE for t-SNARE binding but found instead that the interaction occurs intermolecularly. Thus, complexin organizes the SNAREs into a zigzag topology that, when interposed between the vesicle and plasma membranes, is incompatible with fusion. Complexin cross-links prefusion SNAREs into a zigzag array.,Kummel D, Krishnakumar SS, Radoff DT, Li F, Giraudo CG, Pincet F, Rothman JE, Reinisch KM Nat Struct Mol Biol. 2011 Jul 24;18(8):927-33. doi: 10.1038/nsmb.2101. PMID:21785414[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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