title: Genetic interactions among genes involved in the STT4-PKC1 pathway of Saccharomyces cerevisiae.
abstract: Loss of yeast protein kinase C function results in three distinct phenotypes: staurosporine sensitivity, cell lysis and blockage of cell cycle progression at the G2/M boundary. Genetic analysis of the PKC1/STT1 protein kinase C gene and its interactions with STT4, encoding an upstream phosphatidylinositol 4-kinase, and BCK1, encoding a downstream protein kinase, reveal that they form part of a single pathway. However, the BCK1-20 mutation (a gain-of-function mutation of BCK1) or overexpression of PKC1 cannot suppress all of the phenotypes caused by the loss of STT4 function, strongly suggesting the existence of a branch point between STT4 and PKC1. We also describe the MSS4 gene, a multicopy suppressor of the temperature-sensitive stt4-1 mutation. MSS4 is predicted to encode a hydrophilic protein of 779 amino acid residues and is essential for cell growth. Based on genetic and biochemical data, we suggest that MSS4 acts downstream of STT4, but in a pathway that does not involve PKC1.
authors.affiliation: Department of Biology, Faculty of Science, University of Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Yoshida
authors.forename: Y
authors.initials: Y
authors.lastname: Ohya
authors.forename: A
authors.initials: A
authors.lastname: Nakano
authors.forename: Y
authors.initials: Y
authors.lastname: Anraku
mesh_terms: D019870:1-Phosphatidylinositol 4-Kinase; D000470:Alkaloids / Q000494:pharmacology; D000595:Amino Acid Sequence; D001483:Base Sequence; D002453:Cell Cycle / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics; D004352:Drug Resistance, Microbial / Q000235:genetics; D005800:Genes, Fungal; D016153:Genes, Suppressor; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics; D011493:Protein Kinase C / Q000235:genetics; D011494:Protein Kinases / Q000235:genetics; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D019311:Staurosporine; D013696:Temperature
chemical_list: D000470:Alkaloids; D004271:DNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D011494:Protein Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor); D019870:1-Phosphatidylinositol 4-Kinase; C441760:PIK1 protein, S cerevisiae; D011493:Protein Kinase C; D019311:Staurosporine