title: Ras2 and Ras1 protein phosphorylation in Saccharomyces cerevisiae.
abstract: This work describes the phosphorylation of Saccharomyces cerevisiae Ras proteins and explores the physiological role of the phosphorylation of Ras2 protein. Proteins expressed from activated alleles of RAS were less stable and less phosphorylated than proteins from cells expressing wild-type alleles of RAS. This difference in phosphorylation level did not result from increased signaling through the Ras-cAMP pathway or reflect the primarily GTP-bound nature of activated forms of Ras protein per se. In addition, phosphorylation of Ras protein was not dependent on proper localization of the Ras2 protein to the plasma membrane nor on the interaction of Ras2p with its exchange factor, Cdc25p. The preferred phosphorylation site on Ras2 protein was identified as serine 214. This site, when mutated to alanine, led to promiscuous phosphorylation of Ras2 protein on nearby serine residues. A decrease in phosphorylation may lead to a decrease in signaling through the Ras-cAMP pathway.
authors.affiliation: Division of Genetics, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Whistler
authors.forename: J
authors.initials: J
authors.lastname: Rine
mesh_terms: D000483:Alleles; D018797:Cell Cycle Proteins / Q000378:metabolism; D003470:Culture Media; D000242:Cyclic AMP / Q000378:metabolism; D005559:Formamides / Q000494:pharmacology; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005838:Genotype; D016297:Mutagenesis, Site-Directed; D010449:Peptide Mapping; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010766:Phosphorylation; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D012694:Serine / Q000235:genetics; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism*; D020666:ras-GRF1
chemical_list: D018797:Cell Cycle Proteins; D003470:Culture Media; D005559:Formamides; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D020666:ras-GRF1; D012694:Serine; C031066:formamide; D000242:Cyclic AMP; D010749:Phosphoprotein Phosphatases; C489014:RAS1 protein, S cerevisiae; C489015:RAS2 protein, S cerevisiae; D018631:ras Proteins