Evidence for the direct binding of phosphorylated p53 to sites of DNA breaks in vivo

Shahnaz Al Rashid, G. Dellaire, A. Cuddihy, F. Jalali, M. Vaid, C. Coackley, M. Folkard, Y. Xu, B.P.C. Chen, D.J. Chen, L. Lilge, Kevin Prise, D.P.B. Jones, R.G. Bristow

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85 Citations (Scopus)


Despite a clear link between ataxia-telangiectasia mutated (ATM)-dependent phosphorylation of p53 and cell cycle checkpoint control, the intracellular biology and subcellular localization of p53 phosphoforms during the initial sensing of DNA damage is poorly understood. Using GO-G, confluent primary human diploid fibroblast cultures, we show that endogenous p53, phosphorylated at Ser(15) (p53(Ser15)), accumulates as discrete, dose-dependent and chromatin-bound foci within 30 minutes following induction of DNA breaks or DNA base damage. This biologicafly distinct subpool of p53(Ser15) is ATM dependent and resistant to 26S-proteasomal degradation. p53(Ser15) colocalizes and coimmunoprecipitates with gamma-H2AX with kinetics similar to that of biochemical DNA double-strand break (DNA-dsb) rejoining. Subnuclear micro-beam irradiation studies confirm p53 S,,15 is recruited to sites of DNA damage containing gamma-H2AX, ATM(Ser1981), and DNA-PKcs(Thr2609) in vivo. Furthermore, studies using isogenic human and murine cells, which express Ser(15) or Ser(18) phosphomutant proteins, respectively, show defective nuclear foci formation, decreased induction of p21(WAF) decreased gamma-H2AX association, and altered DNA-dsb kinetics following DNA damage. Our results suggest a unique biology for this p53 phosphoform in the initial steps of DNA damage signaling and implicates ATM-p53 chromatin-based interactions as mediators of cell cycle checkpoint control and DNA repair to prevent carcinogenesis. (Cancer Res 2005; 65(23): 10810-21).
Original languageEnglish
Pages (from-to)10810-10821
Number of pages12
JournalCancer Research
Issue number23
Publication statusPublished - 01 Dec 2005

ASJC Scopus subject areas

  • Cancer Research
  • Oncology


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