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Yeast As a Chassis for Developing Functional Assays to Study Human P53
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Yeast As a Chassis for Developing Functional Assays to Study Human P53

Published on: August 4, 2019

Ribosomal protein S27-like and S27 interplay with p53-MDM2 axis as a target, a substrate and a regulator

X Xiong1, Y Zhao, H He

  • 1Division of Radiation and Cancer Biology, Department of Radiation Oncology, University of Michigan, Ann Arbor, MI 48109, USA.

Oncogene
|December 21, 2010
PubMed

Insights

Ribosomal proteins RPS27L and RPS27 regulate the p53-MDM2 axis. RPS27L, a p53 target and MDM2 substrate, stabilizes p53 levels, impacting cell growth and stress responses.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Cancer Research

Background:

  • Ribosomal proteins influence cellular processes, including tumor suppression.
  • The p53-MDM2 axis is a critical regulator of cell fate, with MDM2 targeting p53 for degradation.
  • RPS27L was previously identified as a p53-inducible gene, suggesting a role in the p53 pathway.

Purpose of the Study:

  • To investigate the regulatory roles of RPS27L and RPS27 in the p53-MDM2 interaction.
  • To elucidate the mechanisms by which RPS27L and RPS27 affect p53 stability and function.
  • To determine the functional consequences of RPS27L and RPS27 interaction with MDM2.

Main Methods:

  • Co-immunoprecipitation assays to assess protein-protein interactions.
  • Western blotting to analyze protein levels and half-lives.
  • siRNA-mediated gene silencing to evaluate functional impacts.
  • Subcellular localization studies using immunofluorescence.

Main Results:

  • RPS27L and RPS27 bind to MDM2, competing with p53 for binding and forming a triplex complex.
  • RPS27L is a short-lived MDM2 substrate, and its degradation is dependent on MDM2 domains.
  • Ectopic expression of RPS27L or RPS27 stabilizes p53 by inhibiting MDM2-mediated ubiquitination, while RPS27L silencing destabilizes p53.
  • RPS27L shuttles to the nucleus upon p53 activation and is crucial for maintaining both cytoplasmic and nuclear p53 levels.

Conclusions:

  • RPS27L and RPS27 are novel regulators of the p53-MDM2 axis.
  • RPS27L acts as a p53 target, an MDM2 substrate, and a crucial regulator of p53 stability and function.
  • The interplay between RPS27L/S27 and the p53-MDM2 pathway offers new insights into cancer biology and potential therapeutic strategies.

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