Related Experiment Video

Updated: Jun 2, 2026

Purification of Ubiquitinated p53 Proteins from Mammalian Cells
10:55

Purification of Ubiquitinated p53 Proteins from Mammalian Cells

Published on: March 21, 2022

UBE4B, a ubiquitin chain assembly factor, is required for MDM2-mediated p53 polyubiquitination and degradation

Hong Wu1, Roger P Leng

  • 1Heritage Medical Research Centre, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB Canada.

Cell Cycle (Georgetown, Tex.)
|May 12, 2011
PubMed

Insights

UBE4B, a ubiquitin ligase, interacts with MDM2 and p53, leading to p53 degradation. Inhibiting this interaction may offer new anticancer therapies by restoring tumor suppressor p53 function.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Ubiquitination Pathways

Background:

  • MDM2 is a key negative regulator of the tumor suppressor p53.
  • MDM2 alone performs insufficient ubiquitination for p53 proteasomal degradation, implying cofactor involvement.
  • The precise mechanisms of MDM2-mediated p53 degradation require further elucidation.

Purpose of the Study:

  • To investigate the role of UBE4B in p53 regulation and degradation.
  • To determine the interaction between UBE4B, MDM2, and p53.
  • To explore novel therapeutic strategies targeting the MDM2-UBE4B interaction.

Main Methods:

  • Co-immunoprecipitation assays to confirm physical interactions between UBE4B, MDM2, and p53.
  • Western blotting to assess p53 protein levels.
  • Analysis of p53-dependent transactivation and apoptosis assays.

Main Results:

  • UBE4B physically interacts with both p53 and MDM2.
  • UBE4B negatively regulates p53 protein levels.
  • UBE4B inhibits p53-dependent transactivation and apoptosis.

Conclusions:

  • UBE4B acts as a crucial E3/E4 ubiquitin ligase in the p53 degradation pathway, working in conjunction with MDM2.
  • Targeting the MDM2-UBE4B interaction presents a potential therapeutic strategy to reactivate p53 for cancer treatment.
  • This approach could contribute to reducing the global cancer burden.

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