title: Tor1 and CK2 kinases control a switch between alternative ribosome biogenesis pathways in a growth-dependent manner.
abstract: Ribosome biogenesis is a major energy-consuming process in the cell that has to be rapidly down-regulated in response to stress or nutrient depletion. The target of rapamycin 1 (Tor1) pathway regulates synthesis of ribosomal RNA (rRNA) at the level of transcription initiation. It remains unclear whether ribosome biogenesis is also controlled directly at the posttranscriptional level. We show that Tor1 and casein kinase 2 (CK2) kinases regulate a rapid switch between a productive and a non-productive pre-rRNA processing pathways in yeast. Under stress, the pre-rRNA continues to be synthesized; however, it is processed differently, and no new ribosomes are produced. Strikingly, the control of the switch does not require the Sch9 kinase, indicating that an unrecognized Tor Complex 1 (TORC1) signaling branch involving CK2 kinase directly regulates ribosome biogenesis at the posttranscriptional level.
authors.affiliation: Biochemistry Center, University of Heidelberg, Heidelberg, Germany.
authors.forename: Isabelle C
authors.initials: IC
authors.lastname: Kos-Braun
authors.affiliation: Biochemistry Center, University of Heidelberg, Heidelberg, Germany.
authors.forename: Ilona
authors.initials: I
authors.lastname: Jung
authors.affiliation: Biochemistry Center, University of Heidelberg, Heidelberg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Koš
mesh_terms: D047390:Casein Kinase II / Q000378:metabolism*; D018869:Heat-Shock Response / Q000187:drug effects; D009154:Mutation / Q000235:genetics; D001678:Organelle Biogenesis; D018384:Oxidative Stress / Q000187:drug effects; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D040901:Proteomics; D012318:RNA Polymerase I / Q000378:metabolism; D012322:RNA Precursors / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional / Q000187:drug effects / Q000235:genetics; D012270:Ribosomes / Q000187:drug effects / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D020123:Sirolimus / Q000494:pharmacology; D014230:Triazoles
chemical_list: D047390:Casein Kinase II; D019869:Phosphatidylinositol 3-Kinases; D012318:RNA Polymerase I; D012322:RNA Precursors; D029701:Saccharomyces cerevisiae Proteins; D020123:Sirolimus; D014230:Triazoles; C405354:4,5,6,7-tetrabromobenzotriazole; C083324:TOR1 protein, S cerevisiae