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.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Animals
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Antigens, Nuclear*
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Base Sequence
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Catalytic Domain
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Cell Line
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Cricetinae
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DNA Damage
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DNA Helicases*
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DNA Repair
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DNA-Activated Protein Kinase
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DNA-Binding Proteins / chemistry
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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HeLa Cells
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Humans
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Ku Autoantigen
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Molecular Sequence Data
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Mutagenesis, Site-Directed
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Nuclear Proteins / chemistry
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism
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Phosphorylation
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Protein Serine-Threonine Kinases / chemistry
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism*
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Protein Subunits
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Radiation Tolerance / genetics
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Sequence Homology, Amino Acid
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Threonine / chemistry
Substances
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Antigens, Nuclear
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DNA-Binding Proteins
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Nuclear Proteins
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Protein Subunits
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Threonine
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DNA-Activated Protein Kinase
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PRKDC protein, human
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Protein Serine-Threonine Kinases
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DNA Helicases
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XRCC5 protein, human
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Xrcc6 protein, human
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Ku Autoantigen