α-SNAP Enhances SNARE Zippering by Stabilizing the SNARE Four-Helix Bundle

Lu Ma, Yuhao Kang, Junyi Jiao, Aleksander A. Rebane, Hyo Keun Cha, Zhiqun Xi, Hong Qu, Yongli Zhang

Research output: Contribution to journalArticlepeer-review

Abstract

Intracellular membrane fusion is mediated by dynamic assembly and disassembly of soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein (SNAP) receptors (SNAREs). α-SNAP guides NSF to disassemble SNARE complexes after membrane fusion. Recent experiments showed that α-SNAP also dramatically enhances SNARE assembly and membrane fusion. How α-SNAP is involved in these opposing activities is not known. Here, we examine the effect of α-SNAP on the stepwise assembly of the synaptic SNARE complex using optical tweezers. We found that α-SNAP destabilized the linker domain (LD) of the SNARE complex but stabilized its C-terminal domain (CTD) through a conformational selection mechanism. In contrast, α-SNAP minimally affected assembly of the SNARE N-terminal domain (NTD), indicating that α-SNAP barely bound the partially assembled trans-SNARE complex. Thus, α-SNAP recognizes the folded CTD for SNARE disassembly with NSF and subtly modulates membrane fusion by altering the stabilities of the SNARE CTD and LD.

Original languageEnglish (US)
Pages (from-to)531-539
Number of pages9
JournalCell Reports
Volume15
Issue number3
DOIs
StatePublished - Apr 19 2016

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology

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