title: Yeast Skn7p activity is modulated by the Sln1p-Ypd1p osmosensor and contributes to regulation of the HOG pathway.
abstract: Activation and control of the yeast HOG (High Osmolarity Glycerol) MAP kinase cascade is accomplished, in part, by a two-component sensory-response circuit comprised of the osmosensing histidine protein kinase Sln1p, the phospho-relay protein Ypd1p, and the response regulator protein Ssk1p. We found that deletion of SLN1 and/or YPD1 reduces reporter gene transcription driven by a second two-component response regulator -- Skn7p. The effect of sln1delta and ypd1delta mutations upon Skn7p activity is dependent on a functional two-component phosphorylation site (D427) in Skn7p, suggesting that Sln1p and Ypd1p may act as phosphodonors for Skn7p. We also observed that loss of PTC1 (a protein serine/threonine phosphatase implicated in negative control of the HOG pathway) in a skn7delta background results in severely retarded growth and in morphological defects. Deletion of either PBS2 or HOG1 alleviates the slow growth phenotype of ptc1delta skn7delta cells, suggesting that Skn7p may participate, in concert with known regulatory components, in modulating HOG pathway activity. The contribution of Skn7p to HOG pathway regulation appears to be modulated by the receiver domain, since non-phosphorylatable Skn7pD427N is unable to fully restore growth to ptc1/skn7 cells.
authors.affiliation: Department of Biology, McGill University, Montreal Quebec, Canada.
authors.forename: T
authors.initials: T
authors.lastname: Ketela
authors.forename: J L
authors.initials: JL
authors.lastname: Brown
authors.forename: R C
authors.initials: RC
authors.lastname: Stewart
authors.forename: H
authors.initials: H
authors.lastname: Bussey
mesh_terms: D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D020928:Mitogen-Activated Protein Kinases; D009154:Mutation; D009997:Osmotic Pressure; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases; D054648:Protein Phosphatase 2; D000071636:Protein Phosphatase 2C; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D047908:Intracellular Signaling Peptides and Proteins; D011993:Recombinant Fusion Proteins; C083962:SKN7 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D011494:Protein Kinases; C102035:YPD1 protein, S cerevisiae; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C088589:HOG1 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases; C083749:SLN1 protein, S cerevisiae; C087358:PTC1 protein, S cerevisiae; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2; D000071636:Protein Phosphatase 2C