Abstract
Cells respond to DNA double-strand breaks by recruiting factors such as the DNA-damage mediator protein MDC1, the p53-binding protein 1 (53BP1), and the breast cancer susceptibility protein BRCA1 to sites of damaged DNA. Here, we reveal that the ubiquitin ligase RNF8 mediates ubiquitin conjugation and 53BP1 and BRCA1 focal accumulation at sites of DNA lesions. Moreover, we establish that MDC1 recruits RNF8 through phosphodependent interactions between the RNF8 forkhead-associated domain and motifs in MDC1 that are phosphorylated by the DNA-damage activated protein kinase ataxia telangiectasia mutated (ATM). We also show that depletion of the E2 enzyme UBC13 impairs 53BP1 recruitment to sites of damage, which suggests that it cooperates with RNF8. Finally, we reveal that RNF8 promotes the G2/M DNA damage checkpoint and resistance to ionizing radiation. These results demonstrate how the DNA-damage response is orchestrated by ATM-dependent phosphorylation of MDC1 and RNF8-mediated ubiquitination.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing
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Amino Acid Motifs
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Amino Acid Sequence
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Ataxia Telangiectasia Mutated Proteins
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BRCA1 Protein / metabolism
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Cell Cycle Proteins / metabolism
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Cell Line, Tumor
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Cell Nucleus Structures / genetics*
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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 / metabolism*
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HeLa Cells
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Humans
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Intracellular Signaling Peptides and Proteins / metabolism
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Molecular Sequence Data
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Nuclear Proteins / chemistry
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Nuclear Proteins / metabolism
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Phosphorylation
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Protein Serine-Threonine Kinases / metabolism
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Protein Structure, Tertiary
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RNA, Small Interfering
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Trans-Activators / chemistry
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Trans-Activators / metabolism
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Tumor Suppressor Proteins / metabolism
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Tumor Suppressor p53-Binding Protein 1
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Ubiquitin / metabolism
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Ubiquitin-Conjugating Enzymes / metabolism
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Ubiquitin-Protein Ligases / metabolism*
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Ubiquitination
Substances
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Adaptor Proteins, Signal Transducing
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BRCA1 Protein
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BRCA1 protein, human
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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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MDC1 protein, human
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Nuclear Proteins
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RNA, Small Interfering
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RNF8 protein, human
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TP53BP1 protein, human
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Trans-Activators
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Tumor Suppressor Proteins
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Tumor Suppressor p53-Binding Protein 1
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Ubiquitin
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UBE2N protein, human
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Ubiquitin-Conjugating Enzymes
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Ubiquitin-Protein Ligases
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ATM protein, human
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Ataxia Telangiectasia Mutated Proteins
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Protein Serine-Threonine Kinases