title: Regulation of the DNA Damage Response by DNA-PKcs Inhibitory Phosphorylation of ATM.
abstract: Ataxia-telangiectasia mutated (ATM) regulates the DNA damage response as well as DNA double-strand break repair through homologous recombination. Here we show that ATM is hyperactive when the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) is chemically inhibited or when the DNA-PKcs gene is deleted in human cells. Pre-incubation of ATM protein with active DNA-PKcs also significantly reduces ATM activity in vitro. We characterize several phosphorylation sites in ATM that are targets of DNA-PKcs and show that phospho-mimetic mutations at these residues significantly inhibit ATM activity and impair ATM signaling upon DNA damage. In contrast, phospho-blocking mutations at one cluster of sites increase the frequency of apoptosis during normal cell growth. DNA-PKcs, which is integral to the non-homologous end joining pathway, thus negatively regulates ATM activity through phosphorylation of ATM. These observations illuminate an important regulatory mechanism for ATM that also controls DNA repair pathway choice.
authors.affiliation: Howard Hughes Medical Institute, University of Texas at Austin, Austin, TX 78712, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Howard Hughes Medical Institute, University of Texas at Austin, Austin, TX 78712, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Ji-Hoon
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Institute for Cancer Genetics, Columbia University Medical Center, New York, NY 10032, USA; Department of Pathology and Cell Biology, Department of Pediatrics, Columbia University Medical Center, New York, NY 10032, USA.
authors.forename: Wenxia
authors.initials: W
authors.lastname: Jiang
authors.affiliation: Institute for Cancer Genetics, Columbia University Medical Center, New York, NY 10032, USA; Department of Pathology and Cell Biology, Department of Pediatrics, Columbia University Medical Center, New York, NY 10032, USA.
authors.forename: Jennie L
authors.initials: JL
authors.lastname: Crowe
authors.affiliation: Institute for Cancer Genetics, Columbia University Medical Center, New York, NY 10032, USA; Department of Pathology and Cell Biology, Department of Pediatrics, Columbia University Medical Center, New York, NY 10032, USA.
authors.forename: Shan
authors.initials: S
authors.lastname: Zha
authors.affiliation: Howard Hughes Medical Institute, University of Texas at Austin, Austin, TX 78712, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA. Electronic address: tpaull@utexas.edu.
authors.forename: Tanya T
authors.initials: TT
authors.lastname: Paull
mesh_terms: D017209:Apoptosis; D064007:Ataxia Telangiectasia Mutated Proteins / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D051747:DNA-Activated Protein Kinase / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D053595:Embryonic Stem Cells / Q000201:enzymology; D005838:Genotype; D057809:HEK293 Cells; D006801:Humans; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress; D010641:Phenotype; D010766:Phosphorylation; D034622:RNA Interference; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection
chemical_list: D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C576325:Atm protein, mouse; D051747:DNA-Activated Protein Kinase; C497263:PRKDC protein, human; C497264:Prkdc protein, mouse
keywords: ATM; DNA repair; DNA-PKcs; cell-cycle checkpoint; phosphorylation; protein kinase