Abstract
DNA double-strand breaks (DSBs), which are generated by ionizing radiation (IR) and a range of other DNA damaging agents, are repaired by homologous recombination (HR) or non-homologous end-joining (NHEJ). Previous studies have shown that NHEJ in Saccharomyces cerevisiae requires the Yku70p-Yku80p heterodimer and a complex consisting of DNA Ligase IV, Lif1p and Nej1p. Here, we report that Nej1p is phosphorylated in response to DNA damage in a manner that relies on the DNA damage checkpoint kinases Mec1p, Rad53p and Dun1p. By using a mutational approach, we have identified a consensus Dun1p phosphorylation site in Nej1p, and mutation of conserved serine residues within it leads to decreased NHEJ efficiency. These data, together with previous findings that Rad55p--a protein involved in HR--is phosphorylated analogously, point to there being a broad signalling network connecting DNA damage checkpoint responses with the regulation of DNA DSB repair activities.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Amino Acid Substitution
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Binding Sites / genetics
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Cell Cycle Proteins / metabolism
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Cell Nucleus / metabolism
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Checkpoint Kinase 2
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DNA Breaks, Double-Stranded*
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DNA Repair
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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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Genetic Complementation Test
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Intracellular Signaling Peptides and Proteins
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Molecular Sequence Data
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Mutagenesis, Site-Directed
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Phosphorylation
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Protein Kinases / metabolism
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Protein Serine-Threonine Kinases / metabolism
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Recombinant Proteins / chemistry
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism
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Recombination, Genetic
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / metabolism
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Saccharomyces cerevisiae Proteins / chemistry
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Saccharomyces cerevisiae Proteins / genetics*
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Saccharomyces cerevisiae Proteins / metabolism*
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Sequence Homology, Amino Acid
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Serine / chemistry
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Signal Transduction
Substances
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Cell Cycle Proteins
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DNA-Binding Proteins
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Intracellular Signaling Peptides and Proteins
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LIF1 protein, S cerevisiae
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NEJ1 protein, S cerevisiae
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Recombinant Proteins
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Saccharomyces cerevisiae Proteins
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Serine
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Protein Kinases
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DUN1 protein, S cerevisiae
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Checkpoint Kinase 2
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MEC1 protein, S cerevisiae
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Protein Serine-Threonine Kinases
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RAD53 protein, S cerevisiae