title: Yeast protein phosphatase 2A-Cdc55 regulates the transcriptional response to hyperosmolarity stress by regulating Msn2 and Msn4 chromatin recruitment.
abstract: We have identified Cdc55, a regulatory B subunit of protein phosphatase 2A (PP2A), as an essential activating factor for stress gene transcription in Saccharomyces cerevisiae. The presence of PP2A-Cdc55 is required for full activation of the environmental stress response mediated by the transcription factors Msn2 and Msn4. We show that PP2A-Cdc55 contributes to sustained nuclear accumulation of Msn2 and Msn4 during hyperosmolarity stress. PP2A-Cdc55 also enhances Msn2-dependent transactivation, required for extended chromatin recruitment of the transcription factor. We analyzed a possible direct regulatory role for PP2A-Cdc55 on the phosphorylation status of Msn2. Detailed mass spectrometric and genetic analysis of Msn2 showed that stress exposure causes immediate transient dephosphorylation of Msn2 which is not dependent on PP2A-Cdc55 activity. Furthermore, the Hog1 mitogen-activated protein kinase pathway activity is not influenced by PP2A-Cdc55. We therefore propose that the PP2A-Cdc55 phosphatase is not involved in cytosolic stress signal perception but is involved in a specific intranuclear mechanism to regulate Msn2 and Msn4 nuclear accumulation and chromatin association under stress conditions.
authors.affiliation: Christian Doppler Laboratory for Proteome Analysis, University of Vienna, Vienna, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Reiter
authors.forename: Eva
authors.initials: E
authors.lastname: Klopf
authors.forename: Veerle
authors.initials: V
authors.lastname: De Wever
authors.forename: Dorothea
authors.initials: D
authors.lastname: Anrather
authors.forename: Andriy
authors.initials: A
authors.lastname: Petryshyn
authors.forename: Andreas
authors.initials: A
authors.lastname: Roetzer
authors.forename: Gerhard
authors.initials: G
authors.lastname: Niederacher
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Roitinger
authors.forename: Ilse
authors.initials: I
authors.lastname: Dohnal
authors.forename: Wolfram
authors.initials: W
authors.lastname: Görner
authors.forename: Karl
authors.initials: K
authors.lastname: Mechtler
authors.forename: Cécile
authors.initials: C
authors.lastname: Brocard
authors.forename: Christoph
authors.initials: C
authors.lastname: Schüller
authors.forename: Gustav
authors.initials: G
authors.lastname: Ammerer
mesh_terms: D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D008969:Molecular Sequence Data; D009997:Osmotic Pressure; D010766:Phosphorylation; D054648:Protein Phosphatase 2 / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D016335:Zinc Fingers
chemical_list: C071246:CDC55 protein, S cerevisiae; D018797:Cell Cycle Proteins; D002843:Chromatin; D004268:DNA-Binding Proteins; C081935:MSN2 protein, S cerevisiae; C081937:MSN4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D054648:Protein Phosphatase 2