title: Regulation of the Saccharomyces cerevisiae Slt2 kinase pathway by the stress-inducible Sdp1 dual specificity phosphatase.
abstract: The Slt2/Mpk1 mitogen-activated protein kinase (MAPK) cell integrity pathway is involved in maintenance of cell shape and integrity during vegetative growth and mating in Saccharomyces cerevisiae. Slt2 is activated by dual phosphorylation of a threonine and tyrosine residue in response to several environmental stresses that perturb cell integrity. Negative regulation of Slt2 is achieved via dephosphorylation by two protein-tyrosine phosphatases, Ptp2 and Ptp3, and a dual specificity phosphatase, Msg5. In this study, we provide genetic and biochemical evidence that the stress-inducible dual specificity phosphatase, Sdp1, negatively regulates Slt2 by direct dephosphorylation. Deletion of SDP1 exacerbated growth defects due to overexpression of Mkk1(p386), a constitutively active mutant of Slt2 MAPK kinase, whereas overexpression of Sdp1 suppressed lethality caused by Mkk1(p386) overexpression. The heat shock-induced phosphorylation level of Slt2 was elevated in an sdp1Delta strain compared with that of the wild type, and heat shock-activated phospho-Slt2 was dephosphorylated by recombinant Sdp1 in vitro. Under normal growth conditions, an Sdp1-GFP fusion protein was localized to both the nucleus and cytoplasm. However, the Sdp1-GFP protein translocated to punctate spots throughout the cell after heat shock. SDP1 transcription was induced by several stress conditions in an Msn2/4-dependent manner but independent of the Rlm1 transcription factor, a downstream target activated by Slt2. Induction of SLT2 by high osmolarity was dependent on Rlm1 transcription factor and Hog1 kinase, suggesting cross-talk between Slt2 and Hog1 MAPK pathways. These studies demonstrate regulation of Slt2 activity and gene expression in coordination with other stress signaling pathways.
authors.affiliation: Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0606, USA.
authors.forename: Ji-Sook
authors.initials: JS
authors.lastname: Hahn
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: Thiele
mesh_terms: D015152:Blotting, Northern; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D004789:Enzyme Activation; D005656:Fungal Proteins / Q000737:chemistry* / Q000378:metabolism; D049452:Green Fluorescent Proteins; D006358:Hot Temperature; D015151:Immunoblotting; D047908:Intracellular Signaling Peptides and Proteins; D008164:Luminescent Proteins / Q000378:metabolism; D048369:MAP Kinase Kinase 1; D008856:Microscopy, Fluorescence; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009154:Mutation; D016366:Open Reading Frames; D009995:Osmosis; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D021381:Protein Transport; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D015398:Signal Transduction; D013696:Temperature; D013997:Time Factors; D015534:Trans-Activators; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism; D014158:Transcription, Genetic; D020798:Two-Hybrid System Techniques
chemical_list: D005656:Fungal Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008164:Luminescent Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; C408468:SCAND1 protein, human; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D049452:Green Fluorescent Proteins; D017346:Protein Serine-Threonine Kinases; C088589:HOG1 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases; C072724:SLT2 protein, S cerevisiae; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; D020929:Mitogen-Activated Protein Kinase Kinases; C516724:PTPN11 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases