title: Utilizing protein phosphatase inhibitors to define PP2A as a regulator of ataxia-telangiectasia mutated.
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.
authors.affiliation: Southern Alberta Cancer Research Institute and Department of Biochemistry & Molecular Biology, University of Calgary, AB, Canada.
authors.forename: Aaron A
authors.initials: AA
authors.lastname: Goodarzi
authors.forename: Pauline
authors.initials: P
authors.lastname: Douglas
authors.forename: Greg B G
authors.initials: GB
authors.lastname: Moorhead
authors.forename: Susan P
authors.initials: SP
authors.lastname: Lees-Miller
mesh_terms: D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D019319:Okadaic Acid / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D010766:Phosphorylation / Q000187:drug effects; D054648:Protein Phosphatase 2; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D025521:Tumor Suppressor Proteins; D019319:Okadaic Acid; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2