title: Yeast HOG1 MAP kinase cascade is regulated by a multistep phosphorelay mechanism in the SLN1-YPD1-SSK1 "two-component" osmosensor.
abstract: An osmosensing mechanism in the budding yeast (Saccharomyces cerevisiae) involves both a two-component signal transducer (Sln1p, Ypd1p and Ssk1p) and a MAP kinase cascade (Ssk2p/Ssk22p, Pbs2p, and Hog1p). The transmembrane protein Sln1p contains an extracellular sensor domain and cytoplasmic histidine kinase and receiver domains, whereas the cytoplasmic protein Ssk1p contains a receiver domain. Ypd1p binds to both Sln1p and Ssk1p and mediates the multistep phosphotransfer reaction (phosphorelay). This phosphorelay system is initiated by the autophosphorylation of Sln1p at His576. This phosphate is then sequentially transferred to Sln1p-Asp-1144, then to Ypd1p-His64, and finally to Ssk1p-Asp554. We propose that the multistep phosphorelay mechanism is a universal signal transduction apparatus utilized both in prokaryotes and eukaryotes.
authors.affiliation: Dana-Farber Cancer Institute and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: F
authors.initials: F
authors.lastname: Posas
authors.forename: S M
authors.initials: SM
authors.lastname: Wurgler-Murphy
authors.forename: T
authors.initials: T
authors.lastname: Maeda
authors.forename: E A
authors.initials: EA
authors.lastname: Witten
authors.forename: T C
authors.initials: TC
authors.lastname: Thai
authors.forename: H
authors.initials: H
authors.lastname: Saito
mesh_terms: D000595:Amino Acid Sequence; D001224:Aspartic Acid / Q000378:metabolism; D001665:Binding Sites; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005800:Genes, Fungal; D006639:Histidine / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D020928:Mitogen-Activated Protein Kinases; D008969:Molecular Sequence Data; D010641:Phenotype; D010766:Phosphorylation; D011494:Protein Kinases; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction / Q000502:physiology; D014882:Water-Electrolyte Balance / Q000502:physiology*
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D047908:Intracellular Signaling Peptides and Proteins; C087199:SSK1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D001224:Aspartic Acid; D006639:Histidine; 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