Munc18a Scaffolds SNARE Assembly to Promote Membrane Fusion

• DOI: 10.1091/mbc.e08-05-0538
• Publication Date: 2008-10-02T01:09:13Z
• Authors: Travis L. Rodkey; Song Liu; Meagan Barry; James A. McNew
• Keywords: SNARE complex; Vesicular Transport Proteins

Munc18a is an SM protein required for SNARE-mediated fusion. The molecular details of how acts to enhance neurosecretion have remained elusive. Here, we use in vitro fusion assays characterize specific interactions between and the neuronal SNAREs rate extent We show that interacts directly functionally with preassembled t-SNARE complex. Analysis point mutations indicates helix C Syntaxin1a NRD Replacement SNAP25b yeast Sec9c had little effect, suggesting has minimal contact within A chimeric Syntaxin built H3 domain Sso1p paired eliminated stimulation fusion, Munc18a/Syntaxin1a contacts are important. Additionally, a Syntaxin1A mutant lacking flexible linker region allows movement abolished These experiments suggest binds assembled complex, positioning them productive VAMP2 binding. In this capacity, serves as platform trans-SNARE complex assembly facilitates efficient membrane