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Purification of Ubiquitinated p53 Proteins from Mammalian Cells
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Purification of Ubiquitinated p53 Proteins from Mammalian Cells

Published on: March 21, 2022

The p53-inducible E3 ubiquitin ligase p53RFP induces p53-dependent apoptosis

Jun Huang1, Liang-Guo Xu, Ting Liu

  • 1Department of Cell Biology and Genetics, College of Life Sciences, Peking University, Beijing 100871, China.

FEBS Letters
|January 24, 2006
PubMed

Insights

p53-inducible RING-finger protein (p53RFP) triggers apoptosis independently of caspases. Its C-terminal domain, not its E3 ligase activity, drives this process, suggesting a role in cell fate decisions.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • Really Interesting New Gene (RING)-in-between ring finger (IBR)-RING domain proteins function as E3 ubiquitin ligases involved in apoptosis regulation.
  • p53RFP is a p53-inducible E3 ubiquitin ligase with a conserved N-terminal RING-IBR-RING domain and a C-terminal domain.

Purpose of the Study:

  • To investigate the mechanism of apoptosis induced by p53RFP.
  • To determine the role of p53RFP's domains and E3 ligase activity in apoptosis.
  • To elucidate p53RFP's function in p53-mediated cellular responses.

Main Methods:

  • Analysis of p53RFP's interaction with E2 ubiquitin-conjugating enzymes (UbcH7, UbcH8, UbcH5).
  • Functional studies of p53RFP domains in inducing apoptosis.
  • Examination of p53RFP's role in p21 ubiquitination and degradation.

Main Results:

  • p53RFP induces p53-dependent, caspase-independent apoptosis.
  • The N-terminal RING-IBR-RING domain mediates interaction with UbcH7 and UbcH8.
  • The conserved C-terminal domain is essential and sufficient for p53RFP-mediated apoptosis, independent of E3 ligase activity.
  • p53RFP is implicated in the degradation of p21, a protein involved in growth arrest and apoptosis antagonism.

Conclusions:

  • p53RFP induces apoptosis through a mechanism that does not require its E3 ubiquitin ligase activity.
  • The C-terminal domain of p53RFP plays a critical role in triggering apoptosis.
  • p53RFP may function to shift cells from p53-mediated growth arrest towards apoptosis.

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