title: Nuclear localization destabilizes the stress-regulated transcription factor Msn2.
abstract: The transcriptional program of yeast cells undergoes dramatic changes during the shift from fermentative growth to respiratory growth. A large part of this response is mediated by the stress responsive transcription factor Msn2. During glucose exhaustion, Msn2 is activated and concentrated in the nucleus. Simultaneously, Msn2 protein levels also drop significantly under this condition. Here we show that the decrease in Msn2 concentration is due to its increased degradation. Moreover, Msn2 levels are also reduced under chronic stress or low protein kinase A (PKA) activity, both conditions that cause a predominant nuclear localization of Msn2. Similar effects were found in msn5 mutant cells that block Msn2 nuclear export. To approximate the effect of low PKA activity on Msn2, we generated a mutant form with alanine substitutions in PKA phosphorylation sites. High expression of this Msn2 mutant is detrimental for growth, suggesting that the increased degradation of nuclear Msn2 might be necessary to adapt cells to low PKA conditions after the diauxic shift or to allow growth under chronic stress conditions.
authors.affiliation: Institute of Biochemistry and Molecular Cell Biology and Ludwig Boltzmann Forschungsstelle for Biochemistry, Max F. Perutz Laboratories, University and BioCenter of Vienna, Dr. Bohr-Gasse 9/5, A-1030 Vienna, Austria.
authors.forename: Erich
authors.initials: E
authors.lastname: Durchschlag
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Reiter
authors.forename: Gustav
authors.initials: G
authors.lastname: Ammerer
authors.forename: Christoph
authors.initials: C
authors.lastname: Schüller
mesh_terms: D021581:Active Transport, Cell Nucleus; D000409:Alanine / Q000737:chemistry; D000483:Alleles; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D000431:Ethanol / Q000494:pharmacology; D005656:Fungal Proteins / Q000502:physiology; D005838:Genotype; D005947:Glucose / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007976:Leupeptins / Q000494:pharmacology; D008957:Models, Genetic; D009154:Mutation; D009841:Oligonucleotides / Q000737:chemistry; D010101:Oxygen Consumption; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011480:Protease Inhibitors / Q000494:pharmacology; D061988:Proteasome Inhibitors; D029701:Saccharomyces cerevisiae Proteins; D004718:Saccharomycetales / Q000378:metabolism*; D013347:Subcellular Fractions; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D007976:Leupeptins; C081935:MSN2 protein, S cerevisiae; D009841:Oligonucleotides; D011480:Protease Inhibitors; D061988:Proteasome Inhibitors; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D049452:Green Fluorescent Proteins; D000431:Ethanol; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D005947:Glucose; D000409:Alanine; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde