Cdc42p functions at the docking stage of yeast vacuole membrane fusion

摘要: Membrane fusion reactions have been considered to be primarily regulated by Rab GTPases. In the model system of homotypic vacuole in yeast Saccharomyces cerevisiae, we show that Cdc42p, a member Rho family GTPases, has direct role membrane fusion. Genetic evidence suggested relationship between Cdc42p and Vtc1p/Nrf1p, central part vacuolar machinery. Vacuoles from cdc42 temperature-sensitive mutants are deficient for at restrictive temperature. Specific amino acid changes on protein surface these define putative interaction domain is crucial its function Affinity-purified antibodies this inhibited vitro reaction. Using kinetic analyses assays subreactions priming, docking post-docking phase reaction, action follows Ypt7p-dependent tethering, but precedes formation trans-SNARE complexes. Thus, our data an effector binding which it regulates reaction