Multiple and distinct strategies of yeast SNAREs to confer the specificity of membrane fusion.
Trans-QabcR-SNARE pairing on opposing membranes is crucial for eukaryotic membrane fusion, but how selective pairs of Qabc- and R-SNARE proteins regulate membrane fusion specificity remains elusive. Here, we studied 14 purified full-length SNAREs that function in yeast endoplasmic reticulum (ER)-Golgi, intra-Golgi, endosomal, and vacuolar transport by comprehensively testing cis-QabcR-SNARE assembly ... and fusogenicity of reconstituted SNARE proteoliposomes. Strikingly, the cognate ER-Golgi and intra-Golgi SNARE-complex assemblies were highly stringent, whereas endosomal and vacuolar SNAREs assembled rather promiscuously into the non-cognate mixed complexes. However, these patterns of cis-SNARE assemblies cannot solely explain their potency to be fusogenic via trans-SNARE pairing: Only the vacuolar 3Q-SNARE combination is fusogenic in the absence of additional components; endosomal SNARE-dependent fusogenicity requires membrane-tethering factors; and ER-Golgi SNAREs can be fusogenic by synergistic actions of tethering factors and the cognate Sec1/Munc18-family protein Sly1p. Thus, our findings uncover multiple and distinct strategies of SNAREs to directly mediate fusion specificity.
Mesh Terms:
Endoplasmic Reticulum, Golgi Apparatus, Lipid Metabolism, Membrane Fusion, Multiprotein Complexes, Protein Biosynthesis, SNARE Proteins, Saccharomyces cerevisiae, Transport Vesicles, Yeasts
Endoplasmic Reticulum, Golgi Apparatus, Lipid Metabolism, Membrane Fusion, Multiprotein Complexes, Protein Biosynthesis, SNARE Proteins, Saccharomyces cerevisiae, Transport Vesicles, Yeasts
Sci Rep
Date: Mar. 04, 2014
PubMed ID: 24589832
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