Mutations in the VPS45 gene, a SEC1 homologue, result in vacuolar protein sorting defects and accumulation of membrane vesicles.

摘要: Genetic analyses of vacuolar protein sorting in Saccharomyces cerevisiae have uncovered a large number mutants (vps) that missort and secrete hydrolases. A small subset vps exhibit temperature-conditional growth phenotype show severe defect the localization soluble proteins, yet maintain near-normal vacuole structure. Here, we report on cloning characterization gene affected one these mutants, VPS45, which has been found to encode member family includes yeast proteins Sec1p, Sly1p Vps33p, as well n-Sec1, UNC18 Rop from other eukaryotic organisms. These are thought participate vesicle-mediated transport events. Polyclonal antiserum raised against TrpE-Vps45 fusion specifically detects stable 67 kDa labeled cell extracts. Subcellular fractionation studies demonstrate majority Vps45p is associated with high-speed membrane pellet fraction Golgi, vesicles and, potentially, endosomal membranes. Significantly, this lacks ER, plasma Overexpression saturates sites associates. vps45 null mutant accumulates vesicles, many were be present clusters. This accumulation potential indicates may facilitate targeting and/or pathway.