Supramolecular SNARE assembly precedes hemifusion in SNARE-mediated membrane fusion.

Formation of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex facilitates intracellular membrane fusion. A single SNARE complex is thought to be insufficient; multiple copies of SNARE complexes must work cooperatively. However, the mechanism by which such a higher-order SNARE protein structure is assembled is unknown. EPR and fluorescence ...
analyses show that at least three copies of target-membrane SNARE proteins self-assemble through the interaction between the transmembrane domains (TMDs), and this multimeric structure serves as scaffolding for trans-SNARE assembly. SNARE core formation in solution induces oligomerization of the TMDs of vesicle-associated SNAREs in the apposing membrane, transiently forming a supramolecular protein structure spanning two membranes. This higher-order protein intermediate evolves, by involving lipid molecules, to the hemifusion state. Hemifusion is subsequently followed by distal leaflet mixing and formation of the cis-SNARE complex.
Mesh Terms:
Electron Spin Resonance Spectroscopy, Fluorescence, Kinetics, Membrane Fusion, Models, Biological, Protein Structure, Quaternary, Protein Structure, Tertiary, Qa-SNARE Proteins, SNARE Proteins, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins
Nat. Struct. Mol. Biol.
Date: Jul. 01, 2008
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