Abstract
Ataxia-telangiectasia mutated (ATM) is a serine/threonine protein kinase that plays a central role in controlling the cellular response to DNA double-strand breaks caused by ionizing radiation. Ionizing radiation induces the autophosphorylation of ATM on serine 1981; however, the precise mechanisms that regulate ATM autophosphorylation are not fully understood. By treating cells with okadaic acid, a cell-permeable protein phosphatase inhibitor, together with assays to quantify the activity of particular protein phosphatases, we have demonstrated that the autophosphorylation of ATM on serine 1981 is regulated by a protein phosphatase 2A-like activity. Here, we describe the series of experiments that employed protein phosphatase inhibitors to establish that ATM was regulated by a type-2A protein phosphatase.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Ataxia Telangiectasia Mutated Proteins
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Cell Cycle Proteins / metabolism*
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Cell Line, Tumor
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Cells, Cultured
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DNA-Binding Proteins / metabolism*
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Electrophoresis, Polyacrylamide Gel
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Enzyme Inhibitors / pharmacology*
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Humans
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Immunoblotting
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Immunoprecipitation
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Okadaic Acid / pharmacology
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Phosphoprotein Phosphatases / antagonists & inhibitors
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Phosphoprotein Phosphatases / metabolism*
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Phosphoprotein Phosphatases / physiology
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Phosphorylation / drug effects
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Protein Phosphatase 2
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Protein Serine-Threonine Kinases / metabolism*
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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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Enzyme Inhibitors
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Tumor Suppressor Proteins
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Okadaic Acid
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ATM protein, human
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Ataxia Telangiectasia Mutated Proteins
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Protein Serine-Threonine Kinases
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Phosphoprotein Phosphatases
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Protein Phosphatase 2