First Author | Yu H | Year | 2018 |
Journal | Proc Natl Acad Sci U S A | Volume | 115 |
Issue | 36 | Pages | E8421-E8429 |
PubMed ID | 30127032 | Mgi Jnum | J:265541 |
Mgi Id | MGI:6197890 | Doi | 10.1073/pnas.1802645115 |
Citation | Yu H, et al. (2018) SNARE zippering requires activation by SNARE-like peptides in Sec1/Munc18 proteins. Proc Natl Acad Sci U S A 115(36):E8421-E8429 |
abstractText | Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) catalyze membrane fusion by forming coiled-coil bundles between membrane bilayers. The SNARE bundle zippers progressively toward the membranes, pulling the lipid bilayers into close proximity to fuse. In this work, we found that the +1 and +2 layers in the C-terminal domains (CTDs) of SNAREs are dispensable for reconstituted SNARE-mediated fusion reactions. By contrast, all CTD layers are required for fusion reactions activated by the cognate Sec1/Munc18 (SM) protein or a synthetic Vc peptide derived from the vesicular (v-) SNARE, correlating with strong acceleration of fusion kinetics. These results suggest a similar mechanism underlying the stimulatory functions of SM proteins and Vc peptide in SNARE-dependent membrane fusion. Unexpectedly, we identified a conserved SNARE-like peptide (SLP) in SM proteins that structurally and functionally resembles Vc peptide. Like Vc peptide, SLP binds and activates target (t-) SNAREs, accelerating the fusion reaction. Disruption of the t-SNARE-SLP interaction inhibits exocytosis in vivo. Our findings demonstrated that a t-SNARE-SLP intermediate must form before SNAREs can drive efficient vesicle fusion. |