Dominant-negative alleles of 14-3-3 proteins cause defects in actin organization and vesicle targeting in the yeast Saccharomyces cerevisiae

14-3-3 Proteins are thought to function as adapters in signaling complexes [1,2], thereby participating in cellular processes including vesicle trafficking and exocytosis [3,4], To delineate further the function of 14-3-3 proteins during vesicle trafficking, we generated dominant-negative alleles of the two 14-3-3 homologues, Bmh1p and Bmh2p, in budding yeast and analyzed their phenotype in respect to exocytosis, Cells overexpressing the carboxy-terminal region of Bmh2p failed to polarize vesicular transport although bulk exocytosis remained unaffected and shelved a disrupted actin cytoskeleton, Our data suggest that 14-3-3 proteins may act primarily on the actin cytoskeleton to regulate vesicle targeting. (C) 1999 Federation of European Biochemical Societies.