Distinct regulatory proteins control the graded transcriptional response to increasing H(2)O(2) levels in fission yeast Schizosaccharomyces pombe.
The signaling pathways that sense adverse stimuli and communicate with the nucleus to initiate appropriate changes in gene expression are central to the cellular stress response. Herein, we have characterized the role of the Sty1 (Spc1) stress-activated mitogen-activated protein kinase pathway, and the Pap1 and Atf1 transcription factors, in regulating the response to H(2)O(2) in the fission yeast Schizosaccharomyces pombe. We find that H(2)O(2) activates the Sty1 pathway in a dose-dependent manner via at least two sensing mechanisms. At relatively low levels of H(2)O(2), a two component-signaling pathway, which feeds into either of the two stress-activated mitogen-activated protein kinase kinase kinases Wak1 or Win1, regulates Sty1 phosphorylation. In contrast, at high levels of H(2)O(2), Sty1 activation is controlled predominantly by a two-component independent mechanism and requires the function of both Wak1 and Win1. Individual transcription factors were also found to function within a limited range of H(2)O(2) concentrations. Pap1 activates target genes primarily in response to low levels of H(2)O(2), whereas Atf1 primarily controls the transcriptional response to high concentrations of H(2)O(2). Our results demonstrate that S. pombe uses a combination of stress-responsive regulatory proteins to gauge and effect the appropriate transcriptional response to increasing concentrations of H(2)O(2).
Quinn
Janet
J
School of Biochemistry and Genetics, The Medical School, University of Newcastle, Newcastle-upon-Tyne NE2 4HH, United Kingdom.
Findlay
Victoria J
VJ
Dawson
Keren
K
Millar
Jonathan B A
JB
Jones
Nic
N
Morgan
Brian A
BA
Toone
W Mark
WM
D051697:Activating Transcription Factor 1; D050976:Basic-Leucine Zipper Transcription Factors; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D005656:Fungal Proteins / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology*; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008954:Models, Biological; D016877:Oxidants / Q000378:metabolism / Q000494:pharmacology; D018384:Oxidative Stress; D000073718:Pancreatitis-Associated Proteins; D010544:Peroxidases / Q000235:genetics; D010766:Phosphorylation; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects* / Q000502:physiology
D051697:Activating Transcription Factor 1; D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D016877:Oxidants; D000073718:Pancreatitis-Associated Proteins; C105096:Pap1 protein, S pombe; C000612141:REG3A protein, human; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors; D006861:Hydrogen Peroxide; D010544:Peroxidases; D020928:Mitogen-Activated Protein Kinases; C095409:sty1 protein, S pombe; D020930:MAP Kinase Kinase Kinases; C109169:wis4 protein, S pombe