Premium
Regulatory Mechanisms of Sec1/Munc18 Proteins in Intracellular Vesicle Fusion
Author(s) -
Yu Haijia,
Liu Yinghui,
Shen Jingshi
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.lb236
Subject(s) - lipid bilayer fusion , snap25 , coiled coil , snare complex , vesicle fusion , microbiology and biotechnology , vesicle , zipper , kiss and run fusion , chemistry , fusion protein , biology , biophysics , synaptic vesicle , membrane , biochemistry , gene , algorithm , computer science , recombinant dna
Intracellular vesicle fusion is mediated by a conserved core machinery composed of SNAREs (soluble N‐ethylmaleimide sensitive factor attachment protein receptors) and SM (Sec1/Munc18) proteins. The core domains of the vesicle‐rooted SNARE (v‐SNARE) and the target membrane associated SNAREs (t‐SNAREs) zipper into a four helix coiled‐coil bundle between two apposed bilayers. The SNARE bundle assembles toward the membranes and provides the energy to bring the two membranes into close apposition to fuse. SM proteins are soluble factors that promote membrane fusion through binding to their cognate trans‐SNARE complexes. It is well known that SM proteins interact with multiple domains on their cognate SNAREs and contribute to the compartmental specificity of intracellular vesicle fusion. However, the molecular mechanism of how SM proteins regulate the vesicle fusion has not been fully elucidated. In a reconstituted fusion system, we observed that the SNAREs themselves were inefficient in driving membrane fusion. The fusion rate was strongly increased by either the cognate SM protein or a Vc peptide corresponding to the C‐terminal half of the v‐SNARE. Further analysis showed that SM proteins promote membrane fusion in a similar manner as the Vc peptide, through restructuring the C‐terminal part of the t‐SNAREs. Support or Funding Information National Institutes of Health grants GM102217