title: The Saccharomyces cerevisiae Sln1p-Ssk1p two-component system mediates response to oxidative stress and in an oxidant-specific fashion.
abstract: Aerobic organisms experience oxidative stress due to generation of reactive oxygen species during normal aerobic metabolism. In addition, environmental gamma and UV radiation, as well as several chemicals also generate reactive oxygen species, which induce oxidative stress. Thus oxidative stress constitutes a major threat to organisms living in aerobic environments. Oxidative stress induces the expression of several genes in yeast Saccharomyces cerevisiae. However, the primary sensor(s) that trigger the response is unknown. This study demonstrates that primary sensors of osmotic stress, the Sln1p-Ssk1p two-component proteins, are involved in sensing oxidative stress specifically induced by hydrogen peroxide and diamide, but not by other oxidants used in the study. Wild type and sln1-ssk1 mutant were treated with hydrogen peroxide, diamide, menadione, UV, and gamma-radiation. Results show that sln1-ssk1 mutant is only sensitive to hydrogen peroxide and diamide but not to other oxidants. S. cerevisiae contains an additional cell surface osmosensor, Sho1p, that targets the osmotic signal to Hog1p. Data is presented that shows Sho1 and Hog1 proteins are also involved in signaling oxidant-specific cellular damage. Furthermore, it is demonstrated that expression of the mammalian homolog of Hog1p provides protection from oxidative stress induced by hydrogen peroxide. These results suggest that Sln1p-Ssk1p and Sho1p signal transduction pathways participate in oxidative stress response. However, this response to oxidative stress is limited to specific oxidants.
authors.affiliation: Johns Hopkins Oncology Center, Baltimore, MD 21231-1000, USA. singhke@jhmi.edu
authors.forename: K K
authors.initials: KK
authors.lastname: Singh
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics; D005609:Free Radicals / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005816:Genetic Complementation Test; D006861:Hydrogen Peroxide / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D016877:Oxidants / Q000378:metabolism; D018384:Oxidative Stress; D010766:Phosphorylation; D011494:Protein Kinases; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction; D014443:Tyrosine / Q000378:metabolism; D014812:Vitamin K / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D005609:Free Radicals; D005656:Fungal Proteins; D047908:Intracellular Signaling Peptides and Proteins; D016877:Oxidants; C087199:SSK1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014812:Vitamin K; D014443:Tyrosine; D006861:Hydrogen Peroxide; D011494:Protein Kinases; C088589:HOG1 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C083749:SLN1 protein, S cerevisiae