4y21
Crystal Structure of Munc13-1 MUN domain
Structural highlights
FunctionUN13A_RAT Plays a role in vesicle maturation during exocytosis as a target of the diacylglycerol second messenger pathway. Involved in neurotransmitter release by acting in synaptic vesicle priming prior to vesicle fusion and participates in the activity-dependent refilling of readily releasable vesicle pool (RRP). Essential for synaptic vesicle maturation in most excitatory/glutamatergic but not inhibitory/GABA-mediated synapses. Also involved in secretory granule priming in insulin secretion.[1] [2] [3] Publication Abstract from PubMedUNC-13-Munc13s have a central function in synaptic-vesicle priming through their MUN domains. However, it is unclear whether this function arises from the ability of the MUN domain to mediate the transition from the Munc18-1-closed syntaxin-1 complex to the SNARE complex in vitro. The crystal structure of the rat Munc13-1 MUN domain now reveals an elongated, arch-shaped architecture formed by alpha-helical bundles, with a highly conserved hydrophobic pocket in the middle. Mutation of two residues (NF) in this pocket abolishes the stimulation caused by the Munc13-1 MUN domain on SNARE-complex assembly and on SNARE-dependent proteoliposome fusion in vitro. Moreover, the same mutation in UNC-13 abrogates synaptic-vesicle priming in Caenorhabditis elegans neuromuscular junctions. These results support the notion that orchestration of syntaxin-1 opening and SNARE-complex assembly underlies the central role of UNC-13-Munc13s in synaptic-vesicle priming. Syntaxin opening by the MUN domain underlies the function of Munc13 in synaptic-vesicle priming.,Yang X, Wang S, Sheng Y, Zhang M, Zou W, Wu L, Kang L, Rizo J, Zhang R, Xu T, Ma C Nat Struct Mol Biol. 2015 Jul;22(7):547-54. doi: 10.1038/nsmb.3038. Epub 2015 Jun, 1. PMID:26030875[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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