title: Cell-cycle control linked to extracellular environment by MAP kinase pathway in fission yeast.
abstract: In fission yeast the onset of mitosis is brought about by Cdc2/Cdc13 kinase, which is inhibited by the Wee1/Mik1 tyrosine kinases and activated by Cdc25 tyrosine phosphatase. This control network integrates many signals, including those that monitor DNA replication, DNA damage and cell size. We report here that a fission yeast MAP kinase pathway links the cell-cycle G2/M control with changes in the extracellular environment that affect cell physiology. Fission yeast spc1- mutants have a G2 delay that is greatly exacerbated by growth in high osmolarity media and nutrient limitation. A lethal interaction of spc1 and cdc25 mutations shows that Spc1 promotes the onset of mitosis. Spc1 is a MAP kinase homologue that is activated by Wis1 kinase in response to osmotic stress and nutrient limitation. Spc1 is inactivated by Pyp1, a phosphatase previously identified as a mitotic inhibitor. Pyp1 dephosphorylates only tyrosine-173 of Spc1, unlike the dual-specificity phosphatases that have been shown to regulate other MAP kinases.
authors.affiliation: Department of Molecular Biology, Scripps Research Institute, La Jolla, California 92037, USA.
authors.forename: K
authors.initials: K
authors.lastname: Shiozaki
authors.forename: P
authors.initials: P
authors.lastname: Russell
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology*; D018797:Cell Cycle Proteins; D003001:Cloning, Molecular; D017931:DNA Primers; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D010766:Phosphorylation; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D012568:Schizosaccharomyces / Q000166:cytology* / Q000201:enzymology; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014443:Tyrosine / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D017931:DNA Primers; D029702:Schizosaccharomyces pombe Proteins; D014443:Tyrosine; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D020928:Mitogen-Activated Protein Kinases; C524689:Spc1 protein, S pombe; C095409:sty1 protein, S pombe; D017027:Protein Tyrosine Phosphatases; C097097:pyp1 protein, S pombe