title: CDC37 is required for p60v-src activity in yeast.
abstract: Mutations in genes encoding the molecular chaperones Hsp90 and Ydj1p suppress the toxicity of the protein tyrosine kinase p60v-src in yeast by reducing its levels or its kinase activity. We describe isolation and characterization of novel p60v-src-resistant, temperature-sensitive cdc37 mutants, cdc37-34 and cdc37-17, which produce less p60v-src than the parental wild-type strain at 23 degrees C. However, p60v-src levels are not low enough to account for the resistance of these strains. Asynchronously growing cdc37-34 and cdc37-17 mutants arrest in G1 and G2/M when shifted from permissive temperatures (23 degrees C) to the restrictive temperature (37 degrees C), but hydroxyurea-synchronized cdc37-34 and cdc37-17 mutants arrest in G2/M when released from the hydroxyurea block and shifted from 23 to 37 degrees C. The previously described temperature-sensitive cdc37-1 mutant is p60v-src-sensitive and produces wild-type amounts of p60v-src at permissive temperatures but becomes p60v-src-resistant at its restrictive temperature, 38 degrees C. In all three cdc37 mutants, inactivation of Cdc37p by incubation at 38 degrees C reduces p60v-src-dependent tyrosine phosphorylation of yeast proteins to low or undetectable levels. Also, p60v-src levels are enriched in urea-solubilized extracts and depleted in detergent-solubilized extracts of all three cdc37 mutants prepared from cells incubated at the restrictive temperature. These results suggest that Cdc37p is required for maintenance of p60v-src in a soluble, biologically active form.
authors.affiliation: Department of Biochemistry, Wayne State University Medical School, Detroit, Michigan 48201, USA.
authors.forename: B
authors.initials: B
authors.lastname: Dey
authors.forename: J J
authors.initials: JJ
authors.lastname: Lightbody
authors.forename: F
authors.initials: F
authors.lastname: Boschelli
mesh_terms: D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D029721:Drosophila Proteins; D004789:Enzyme Activation; D016193:G1 Phase / Q000235:genetics; D016195:G2 Phase / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D005804:Genes, Lethal; D016153:Genes, Suppressor; D008938:Mitosis / Q000235:genetics; D018832:Molecular Chaperones; D009154:Mutation; D015688:Oncogene Protein pp60(v-src) / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D012995:Solubility; D013696:Temperature; D014443:Tyrosine / Q000378:metabolism; D014508:Urea / Q000737:chemistry; D015003:Yeasts / Q000235:genetics*
chemical_list: D018797:Cell Cycle Proteins; D029721:Drosophila Proteins; D018832:Molecular Chaperones; D012967:Sodium Dodecyl Sulfate; D014443:Tyrosine; D014508:Urea; D015688:Oncogene Protein pp60(v-src)