title: Torin1-mediated TOR kinase inhibition reduces Wee1 levels and advances mitotic commitment in fission yeast and HeLa cells.
abstract: The target of rapamycin (TOR) kinase regulates cell growth and division. Rapamycin only inhibits a subset of TOR activities. Here we show that in contrast to the mild impact of rapamycin on cell division, blocking the catalytic site of TOR with the Torin1 inhibitor completely arrests growth without cell death in Schizosaccharomyces pombe. A mutation of the Tor2 glycine residue (G2040D) that lies adjacent to the key Torin-interacting tryptophan provides Torin1 resistance, confirming the specificity of Torin1 for TOR. Using this mutation, we show that Torin1 advanced mitotic onset before inducing growth arrest. In contrast to TOR inhibition with rapamycin, regulation by either Wee1 or Cdc25 was sufficient for this Torin1-induced advanced mitosis. Torin1 promoted a Polo and Cdr2 kinase-controlled drop in Wee1 levels. Experiments in human cell lines recapitulated these yeast observations: mammalian TOR (mTOR) was inhibited by Torin1, Wee1 levels declined and mitotic commitment was advanced in HeLa cells. Thus, the regulation of the mitotic inhibitor Wee1 by TOR signalling is a conserved mechanism that helps to couple cell cycle and growth controls.
authors.affiliation: Faculty of Life Sciences, University of Manchester, Michael Smith Building, Manchester M13 9PT, UK.
authors.forename: Jane
authors.initials: J
authors.lastname: Atkin
authors.forename: Lenka
authors.initials: L
authors.lastname: Halova
authors.forename: Jennifer
authors.initials: J
authors.lastname: Ferguson
authors.forename: James R
authors.initials: JR
authors.lastname: Hitchin
authors.forename: Agata
authors.initials: A
authors.lastname: Lichawska-Cieslar
authors.forename: Allan M
authors.initials: AM
authors.lastname: Jordan
authors.forename: Jonathon
authors.initials: J
authors.lastname: Pines
authors.forename: Claudia
authors.initials: C
authors.lastname: Wellbrock
authors.forename: Janni
authors.initials: J
authors.lastname: Petersen
mesh_terms: D000595:Amino Acid Sequence; D020134:Catalytic Domain; D018797:Cell Cycle Proteins / Q000378:metabolism*; D016923:Cell Death; D004351:Drug Resistance; D059585:G1 Phase Cell Cycle Checkpoints; D006367:HeLa Cells; D006801:Humans; D000076222:Mechanistic Target of Rapamycin Complex 1; D000076225:Mechanistic Target of Rapamycin Complex 2; D008938:Mitosis / Q000187:drug effects*; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000037:antagonists & inhibitors / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D009287:Naphthyridines / Q000494:pharmacology*; D009687:Nuclear Proteins / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D021381:Protein Transport; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D012568:Schizosaccharomyces / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development*; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism*; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D000076222:Mechanistic Target of Rapamycin Complex 1; D000076225:Mechanistic Target of Rapamycin Complex 2; D046912:Multiprotein Complexes; D009287:Naphthyridines; D009687:Nuclear Proteins; D019869:Phosphatidylinositol 3-Kinases; D011505:Protein-Tyrosine Kinases; D029702:Schizosaccharomyces pombe Proteins; D058570:TOR Serine-Threonine Kinases; C553294:1-(4-(4-propionylpiperazin-1-yl)-3-(trifluoromethyl)phenyl)-9-(quinolin-3-yl)benzo(h)(1,6)naphthyridin-2(1H)-one; C068689:wee1 protein, S pombe; C513100:tor2 protein, S pombe; C499349:WEE1 protein, human
keywords: HeLa; S. pombe; TOR; Torin1; Wee1