May 2005
Volume 46, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2005
Dephosphorylation of the Tumor Suppressor, p53 by the Protein Serine/Threonine Phosphatase–1 Promotes Cell Survival
Author Affiliations & Notes
  • D.W. Li
    The Hormel Institute, Univ of Minnesota, Austin, MN
  • J.–P. Liu
    The Hormel Institute, Univ of Minnesota, Austin, MN
  • X.–Q. Huang
    College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
  • H. Feng
    College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
  • Y. Liu
    College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
  • Q. Yan
    College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
  • W.–B. Liu
    College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
  • L. Gong
    College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
  • M. Deng
    College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
  • S.–M. Sun
    College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
  • Footnotes
    Commercial Relationships  D.W. Li, None; J. Liu, None; X. Huang, None; H. Feng, None; Y. Liu, None; Q. Yan, None; W. Liu, None; L. Gong, None; M. Deng, None; S. Sun, None.
  • Footnotes
    Support  NIH/NEI, The Hormel Foundation, Lotus Scholar Professorship Funds
Investigative Ophthalmology & Visual Science May 2005, Vol.46, 3868. doi:
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      D.W. Li, J.–P. Liu, X.–Q. Huang, H. Feng, Y. Liu, Q. Yan, W.–B. Liu, L. Gong, M. Deng, S.–M. Sun; Dephosphorylation of the Tumor Suppressor, p53 by the Protein Serine/Threonine Phosphatase–1 Promotes Cell Survival . Invest. Ophthalmol. Vis. Sci. 2005;46(13):3868.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Abstract: : Purpose: We have previously demonstrated that the serine/threonine protein phosphatase–1 (PP–1) plays an important role in promoting cell survival. However, the molecular mechanism by which PP–1 promotes survival remains largely unknown. In the present study, we provide evidence to show that PP–1 can negatively regulate p53 function to promote survival of human lens epithelial cells. Methods: The function of p53 in mediating apoptosis was analyzed with RNAi. The phosphorylation status of p53 was analyzed with Western bot analysis. The dephosphorylation of p53 by protein phosphatase–1 was explored with co–immunoprecipitation, and in vitro and in vivo dephosphorylation assays. Results: Co–immunoprecipitation, in vitro and in vivo dephosphorylation assays, overexpression and RNAi silence of PP–1 all show that PP–1 can dephosphorylate p53 at Ser–15 and Ser–37. Moreover, dephosphorylation of p53 at these sites by PP–1 decreases the transcriptional activity of p53. As a result, the downstream proapoptotic genes such as bax are down–regulated and the apoptotic events are largely abrogated. Conclusions: Our results demonstrate that one of the molecular mechanisms by which PP–1 promotes cell survival is derived from its ability to dephosphorylate p53, and thus negatively regulate p53–dependent death pathway. Supported by NIH/NEI, the Hormel Foundation, and the Lotus Scholar Professorship Funds from Hunan Province Government and Hunan Normal University. None.

Keywords: signal transduction • phosphorylation • cell death/apoptosis 
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