title: Initiation of the yeast G0 program requires Igo1 and Igo2, which antagonize activation of decapping of specific nutrient-regulated mRNAs.
abstract: Growth factors and essential nutrients are key controllers of eukaryotic cell proliferation. In their absence, cells may enter into a quiescent (G0) state. In yeast, nitrogen and/or carbon limitation causes downregulation of the conserved TORC1 and PKA signaling pathways and consequently activation of Rim15, a member of the PAS protein kinase family. Rim15 orchestrates the initiation of the G0 program in part by coordinating transcription of Msn2/4- and/or Gis1-dependent genes with posttranscriptional protection of the corresponding mRNAs via direct phosphorylation of Igo1/2. Here, we show that several factors including Ccr4, the Lsm-Pat1 complex, and Dhh1, which are implicated in mRNA decapping activation, participate in the decay of specific mRNAs during initiation of the G0 program when Igo1/2 are absent. Accordingly, Igo1/2 likely play a key role in preventing the decapping and subsequent 5'-3' degradation of a set of nutrient-regulated mRNAs that are critical for cell differentiation and chronological life span.
authors.affiliation: Division of Biochemistry, Department of Medicine, University of Fribourg, Fribourg, Switzerland.
authors.forename: Xuan
authors.initials: X
authors.lastname: Luo
authors.forename: Nicolas
authors.initials: N
authors.lastname: Talarek
authors.forename: Claudio
authors.initials: C
authors.lastname: De Virgilio
mesh_terms: D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004722:Endoribonucleases / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D006360:Heat-Shock Proteins / Q000378:metabolism; D008958:Models, Molecular; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D020871:RNA Stability; D012331:RNA, Fungal / Q000235:genetics; D016192:Resting Phase, Cell Cycle; D012260:Ribonucleases / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism; D015533:Transcriptional Activation
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C499528:HSP26 protein, S cerevisiae; D006360:Heat-Shock Proteins; C549818:Igo1 protein, S cerevisiae; C549819:Igo2 protein, S cerevisiae; C081935:MSN2 protein, S cerevisiae; C081937:MSN4 protein, S cerevisiae; D012331:RNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C030052:mRNA decapping enzymes; D011494:Protein Kinases; C410736:Rim15 protein, S cerevisiae; C078657:CCR4 protein, S cerevisiae; D004722:Endoribonucleases; D012260:Ribonucleases; C445083:DHH1 protein, S cerevisiae; D053487:DEAD-box RNA Helicases