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Yeast As a Chassis for Developing Functional Assays to Study Human P53
14:57

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

Published on: August 4, 2019

Functional p53 chimeras containing the Epstein-Barr virus Gly-Ala repeat are protected from Mdm2- and HPV-E6-induced

Stijn Heessen1, Ainars Leonchiks, Natalia Issaeva

  • 1Microbiology and Tumor Biology Center, and Cancer Center Karolinska, Karolinska Institute, S-17177 Stockholm, Sweden.

Proceedings of the National Academy of Sciences of the United States of America
|January 24, 2002
PubMed

Insights

The Gly-Ala repeat (GAr) of Epstein-Barr virus nuclear antigen-1 protects the tumor suppressor p53 from degradation. This protection enhances p53

Area of Science:

  • Molecular Biology
  • Oncology
  • Virology

Background:

  • Tumor suppressor p53 inactivation via proteasomal degradation is common in cancer.
  • Epstein-Barr virus nuclear antigen-1's Gly-Ala repeat (GAr) inhibits proteasomal degradation of various substrates.

Purpose of the Study:

  • To investigate if the GAr can protect p53 from proteasomal degradation.
  • To assess the functional consequences of GAr-mediated p53 stabilization.

Main Methods:

  • Construction of p53 chimeras incorporating GAr domains.
  • Assessment of p53 ubiquitination and proteasome interaction.
  • Evaluation of p53 target gene transactivation, cell cycle arrest, and apoptosis induction.

Main Results:

  • p53-GAr chimeras were protected from degradation by MDM2 and E6AP.
  • Chimeras remained ubiquitinated and interacted with the proteasome's S5a subunit.
  • GAr-stabilized p53 retained transactivation capacity, induced cell cycle arrest and apoptosis, and inhibited tumor cell growth.

Conclusions:

  • The GAr domain can confer resistance to p53 proteasomal degradation.
  • GAr-mediated stabilization of p53 preserves its tumor-suppressive functions.
  • This strategy shows potential for enhancing anti-tumor activity in cancer therapy.

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