title: Ataxia-telangiectasia mutated (ATM)-dependent activation of ATR occurs through phosphorylation of TopBP1 by ATM.
abstract: ATM (ataxia-telangiectasia mutated) is necessary for activation of Chk1 by ATR (ATM and Rad3-related) in response to double-stranded DNA breaks (DSBs) but not to DNA replication stress. TopBP1 has been identified as a direct activator of ATR. We show that ATM regulates Xenopus TopBP1 by phosphorylating Ser-1131 and thereby strongly enhancing association of TopBP1 with ATR. Xenopus egg extracts containing a mutant of TopBP1 that cannot be phosphorylated on Ser-1131 are defective in the ATR-dependent phosphorylation of Chk1 in response to DSBs but not to DNA replication stress. Thus, TopBP1 is critical for the ATM-dependent activation of ATR following production of DSBs in the genome.
authors: Division of Biology 216-76, California Institute of Technology, Pasadena, California 91125, USA.
authors: Hae Yong
authors: HY
authors: Yoo
authors: Akiko
authors: A
authors: Kumagai
authors: Anna
authors: A
authors: Shevchenko
authors: Andrej
authors: A
authors: Shevchenko
authors: William G
authors: WG
authors: Dunphy
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D006801:Humans; D008969:Molecular Sequence Data; D009865:Oocytes / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D012694:Serine / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis / Q000502:physiology*
chemical_list: C495984:ATRIP protein, Xenopus; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D011994:Recombinant Proteins; C509993:TopBP1 protein, Xenopus; D025521:Tumor Suppressor Proteins; D029867:Xenopus Proteins; D012694:Serine; C576898:Atr protein, Xenopus; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases