Abstract
The Ataxia-Telangiectasia mutated (ATM) kinase is regarded as the major regulator of the cellular response to DNA double strand breaks (DSBs). In response to DSBs, ATM dimers dissociate into active monomers in a process promoted by the Mre11-Rad50-Nbs1 (MRN) complex. ATM can also be activated by oxidative stress directly in the form of exposure to H2O2. The active ATM in this case is a disulfide-crosslinked dimer containing 2 or more disulfide bonds. Mutation of a critical cysteine residue in the FATC domain involved in disulfide bond formation specifically blocks ATM activation by oxidative stress. Here we show that ATM activation by DSBs is inhibited in the presence of H2O2 because oxidation blocks the ability of MRN to bind to DNA. However, ATM activation via direct oxidation by H2O2 complements the loss of MRN/DSB-dependent activation and contributes significantly to the overall level of ATM activity in the presence of both DSBs and oxidative stress.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Ataxia Telangiectasia / genetics
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Ataxia Telangiectasia / metabolism
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Ataxia Telangiectasia Mutated Proteins
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Cell Cycle Proteins / classification
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism*
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DNA Damage
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DNA-Binding Proteins / classification
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Enzyme Activation
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Humans
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Molecular Sequence Data
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Mutation
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Oxidative Stress*
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Phylogeny
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Protein Serine-Threonine Kinases / classification
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism*
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Sequence Alignment
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Tumor Suppressor Proteins / classification
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Tumor Suppressor Proteins / genetics
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Tumor Suppressor Proteins / metabolism*
Substances
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Cell Cycle Proteins
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DNA-Binding Proteins
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Tumor Suppressor Proteins
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ATM protein, human
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Ataxia Telangiectasia Mutated Proteins
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Protein Serine-Threonine Kinases