TY - JOUR
T1 - SNARE assembly enlightened by cryo-EM structures of a synaptobrevin–Munc18-1–syntaxin-1 complex
AU - Stepien, Karolina P.
AU - Xu, Junjie
AU - Zhang, Xuewu
AU - Bai, Xiao Chen
AU - Rizo, Josep
N1 - Publisher Copyright:
Copyright © 2022 The Authors, some rights reserved.
PY - 2022/6
Y1 - 2022/6
N2 - Munc18-1 forms a template to organize assembly of the neuronal SNARE complex that triggers neurotransmitter release, binding first to a closed conformation of syntaxin-1 where its amino-terminal region interacts with the SNARE motif, and later binding to synaptobrevin. However, the mechanism of SNARE complex assembly remains unclear. Here, we report two cryo-EM structures of Munc18-1 bound to cross-linked syntaxin-1 and synaptobrevin. The structures allow visualization of how syntaxin-1 opens and reveal how part of the syntaxin-1 amino-terminal region can help nucleate interactions between the amino termini of the syntaxin-1 and synaptobrevin SNARE motifs, while their carboxyl termini bind to distal sites of Munc18-1. These observations, together with mutagenesis, SNARE complex assembly experiments, and fusion assays with reconstituted proteoliposomes, support a model whereby these interactions are critical to initiate SNARE complex assembly and multiple energy barriers enable diverse mechanisms for exquisite regulation of neurotransmitter release.
AB - Munc18-1 forms a template to organize assembly of the neuronal SNARE complex that triggers neurotransmitter release, binding first to a closed conformation of syntaxin-1 where its amino-terminal region interacts with the SNARE motif, and later binding to synaptobrevin. However, the mechanism of SNARE complex assembly remains unclear. Here, we report two cryo-EM structures of Munc18-1 bound to cross-linked syntaxin-1 and synaptobrevin. The structures allow visualization of how syntaxin-1 opens and reveal how part of the syntaxin-1 amino-terminal region can help nucleate interactions between the amino termini of the syntaxin-1 and synaptobrevin SNARE motifs, while their carboxyl termini bind to distal sites of Munc18-1. These observations, together with mutagenesis, SNARE complex assembly experiments, and fusion assays with reconstituted proteoliposomes, support a model whereby these interactions are critical to initiate SNARE complex assembly and multiple energy barriers enable diverse mechanisms for exquisite regulation of neurotransmitter release.
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U2 - 10.1126/sciadv.abo5272
DO - 10.1126/sciadv.abo5272
M3 - Article
C2 - 35731863
AN - SCOPUS:85132601748
SN - 2375-2548
VL - 8
JO - Science Advances
JF - Science Advances
IS - 25
M1 - eabo5272
ER -