3puk
From Proteopedia
Re-refinement of the crystal structure of Munc18-3 and Syntaxin4 N-peptide complex
Structural highlights
Function[STXB3_MOUSE] Together with STX4 and VAMP2, may play a role in insulin-dependent movement of GLUT4 and in docking/fusion of intracellular GLUT4-containing vesicles with the cell surface in adipocytes.[1] [STX4_MOUSE] Plasma membrane t-SNARE that mediates docking of transport vesicles. Necessary for the translocation of SLC2A4 from intracellular vesicles to the plasma membrane. Together with STXB3 and VAMP2, may also play a role in docking/fusion of intracellular GLUT4-containing vesicles with the cell surface in adipocytes and in docking of synaptic vesicles at presynaptic active zones.[2] [3] [4] Publication Abstract from PubMedMunc18-1 and Syntaxin1 are essential proteins for SNARE-mediated neurotransmission. Munc18-1 participates in synaptic vesicle fusion via dual roles: as a docking/chaperone protein by binding closed Syntaxin1, and as a fusion protein that binds SNARE complexes in a Syntaxin1 N-peptide dependent manner. The two roles are associated with a closed-open Syntaxin1 conformational transition. Here, we show that Syntaxin N-peptide binding to Munc18-1 is not highly selective, suggesting that other parts of the SNARE complex are involved in binding to Munc18-1. We also find that Syntaxin1, with an N peptide and a physically anchored C terminus, binds to Munc18-1 and that this complex can participate in SNARE complex formation. We report a Munc18-1-N-peptide crystal structure that, together with other data, reveals how Munc18-1 might transit from a conformation that binds closed Syntaxin1 to one that may be compatible with binding open Syntaxin1 and SNARE complexes. Our results suggest the possibility that structural transitions occur in both Munc18-1 and Syntaxin1 during their binary interaction. We hypothesize that Munc18-1 domain 3a undergoes a conformational change that may allow coiled-coil interactions with SNARE complexes. Possible roles for Munc18-1 domain 3a and Syntaxin1 N-peptide and C-terminal anchor in SNARE complex formation.,Hu SH, Christie MP, Saez NJ, Latham CF, Jarrott R, Lua LH, Collins BM, Martin JL Proc Natl Acad Sci U S A. 2010 Dec 30. PMID:21193638[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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