TY - JOUR
T1 - Munc18-1 is crucial to overcome the inhibition of synaptic vesicle fusion by αSNAP
AU - Stepien, Karolina P.
AU - Prinslow, Eric A.
AU - Rizo, Josep
N1 - Funding Information:
We thank William Wickner and Reinhard Jahn for insightful comments on the manuscript, Minglei Zhao for providing the plasmid to express NSF, and Yun-Zu Pan, Bradley Quade, and Junjie Xu for providing purified proteins. The Agilent DD2 console of the 800 MHz spectrometer used for the research presented here was purchased with a shared instrumentation grants from the NIH (S10OD018027 to J.R.). Eric Prinslow was supported by NIH Training Grant T32 GM008297. This work was supported by grant I-1304 from the Welch Foundation (to J.R.) and by NIH Research Project Award R35 NS097333 (to J.R.).
Publisher Copyright:
© 2019, The Author(s).
PY - 2019/12/1
Y1 - 2019/12/1
N2 - Munc18-1 and Munc13-1 orchestrate assembly of the SNARE complex formed by syntaxin-1, SNAP-25 and synaptobrevin, allowing exquisite regulation of neurotransmitter release. Non-regulated neurotransmitter release might be prevented by αSNAP, which inhibits exocytosis and SNARE-dependent liposome fusion. However, distinct mechanisms of inhibition by αSNAP were suggested, and it is unknown how such inhibition is overcome. Using liposome fusion assays, FRET and NMR spectroscopy, here we provide a comprehensive view of the mechanisms underlying the inhibitory functions of αSNAP, showing that αSNAP potently inhibits liposome fusion by: binding to syntaxin-1, hindering Munc18-1 binding; binding to syntaxin-1-SNAP-25 heterodimers, precluding SNARE complex formation; and binding to trans-SNARE complexes, preventing fusion. Importantly, inhibition by αSNAP is avoided only when Munc18-1 binds first to syntaxin-1, leading to Munc18-1-Munc13-1-dependent liposome fusion. We propose that at least some of the inhibitory activities of αSNAP ensure that neurotransmitter release occurs through the highly-regulated Munc18-1-Munc13-1 pathway at the active zone.
AB - Munc18-1 and Munc13-1 orchestrate assembly of the SNARE complex formed by syntaxin-1, SNAP-25 and synaptobrevin, allowing exquisite regulation of neurotransmitter release. Non-regulated neurotransmitter release might be prevented by αSNAP, which inhibits exocytosis and SNARE-dependent liposome fusion. However, distinct mechanisms of inhibition by αSNAP were suggested, and it is unknown how such inhibition is overcome. Using liposome fusion assays, FRET and NMR spectroscopy, here we provide a comprehensive view of the mechanisms underlying the inhibitory functions of αSNAP, showing that αSNAP potently inhibits liposome fusion by: binding to syntaxin-1, hindering Munc18-1 binding; binding to syntaxin-1-SNAP-25 heterodimers, precluding SNARE complex formation; and binding to trans-SNARE complexes, preventing fusion. Importantly, inhibition by αSNAP is avoided only when Munc18-1 binds first to syntaxin-1, leading to Munc18-1-Munc13-1-dependent liposome fusion. We propose that at least some of the inhibitory activities of αSNAP ensure that neurotransmitter release occurs through the highly-regulated Munc18-1-Munc13-1 pathway at the active zone.
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U2 - 10.1038/s41467-019-12188-4
DO - 10.1038/s41467-019-12188-4
M3 - Article
C2 - 31548544
AN - SCOPUS:85072562140
SN - 2041-1723
VL - 10
JO - Nature communications
JF - Nature communications
IS - 1
M1 - 4326
ER -