Activation of the ATM kinase by ionizing radiation and phosphorylation of p53

Christine E. Canman, Dae Sik Lim, Karlene A. Cimprich, Yoichi Taya, Katsuyuki Tamai, Kazuyasu Sakaguchi, Ettore Appella, Michael B. Kastan, Janet D. Siliciano

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1633 Scopus citations


The p53 tumor suppressor protein is activated and phosphorylated on serine-15 in response to various DNA damaging agents. The gene product mutated in ataxia telangiectasia. ATM, acts upstream of p53 in a signal transduction pathway initiated by ionizing radiation. Immunoprecipitated ATM had intrinsic protein kinase activity and phosphorylated p53 on serine-15 in a manganese-dependent manner. Ionizing radiation, but not ultraviolet radiation, rapidly enhanced this p53-directed kinase activity of endogenous ATM. These observations, along with the fact that phosphorylation of p53 on serine-15 in response to ionizing radiation is reduced in ataxia telangiectasia cells, suggest that ATM is a protein kinase that phosphorylates p53 in vivo.

Original languageEnglish (US)
Pages (from-to)1677-1679
Number of pages3
Issue number5383
StatePublished - Sep 11 1998

ASJC Scopus subject areas

  • General


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