title: Autophosphorylation of the DNA-dependent protein kinase catalytic subunit is required for rejoining of DNA double-strand breaks.
abstract: Nonhomologous end-joining (NHEJ) is the predominant pathway that repairs DNA double-strand breaks (DSBs) in mammalian cells. The DNA-dependent protein kinase (DNA-PK), consisting of Ku and DNA-PK catalytic subunit (DNA-PKcs), is activated by DNA in vitro and is required for NHEJ. We report that DNA-PKcs is autophosphorylated at Thr2609 in vivo in a Ku-dependent manner in response to ionizing radiation. Phosphorylated DNA-PKcs colocalizes with both gamma-H2AX and 53BP1 after DNA damage. Mutation of Thr2609 to Ala leads to radiation sensitivity and impaired DSB rejoining. These findings establish that Ku-dependent phosphorylation of DNA-PKcs at Thr2609 is required for the repair of DSBs by NHEJ.
authors.affiliation: Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Doug W
authors.initials: DW
authors.lastname: Chan
authors.forename: Benjamin Ping-Chi
authors.initials: BP
authors.lastname: Chen
authors.forename: Sheela
authors.initials: S
authors.lastname: Prithivirajsingh
authors.forename: Akihiro
authors.initials: A
authors.lastname: Kurimasa
authors.forename: Michael D
authors.initials: MD
authors.lastname: Story
authors.forename: Jun
authors.initials: J
authors.lastname: Qin
authors.forename: David J
authors.initials: DJ
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D034961:Antigens, Nuclear; D001483:Base Sequence; D020134:Catalytic Domain; D002460:Cell Line; D006224:Cricetinae; D004249:DNA Damage; D004265:DNA Helicases; D004260:DNA Repair; D051747:DNA-Activated Protein Kinase; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D000072200:Ku Autoantigen; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits; D011836:Radiation Tolerance / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013912:Threonine / Q000737:chemistry
chemical_list: D034961:Antigens, Nuclear; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D021122:Protein Subunits; D013912:Threonine; D051747:DNA-Activated Protein Kinase; C497263:PRKDC protein, human; D017346:Protein Serine-Threonine Kinases; D004265:DNA Helicases; C106893:XRCC5 protein, human; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen