Apoptin induces apoptosis by changing the equilibrium between the stability of TAp73 and DNp73 isoforms through ubiquitin ligase PIR2

P. Taebunpakul, B. S. Sayan, M. Flinterman, P. Klanrit, J. Gäken, E. W. Odell, G. Melino, M. Tavassoli

Research output: Contribution to journalArticle

Abstract

Apoptin, a protein derived from the chicken anaemia virus, induces cell death in various cancer cells but shows little or no cytotoxicity in normal cells. The mechanism of apoptin-induced cell death is currently unknown but it appears to induce apoptosis independent of p53 status. Here we show that p73, a p53 family member, is important in apoptin-induced apoptosis. In p53 deficient and/or mutated cells, apoptin induced the expression of TAp73 leading to the induction of apoptosis. Knockdown of p73 using siRNA resulted in a significant reduction in apoptin-induced cytotoxicity. The p53 and p73 pro-apoptotic target PUMA plays an important role in apoptin-induced cell death as knockdown of PUMA significantly reduced cell sensitivity to apoptin. Importantly, apoptin expression resulted in a marked increase in TAp73 protein stability. Investigation into the mechanisms of TAp73 stability showed that apoptin induced the expression of the ring finger domain ubiquitin ligase PIR2 which is involved in the degradation of the anti-apoptotic DNp73 isoform. Collectively, our results suggest a novel mechanism of apoptin-induced apoptosis through increased TAp73 stability and induction of PIR2 resulting in the degradation of DNp73 and activation of pro-apoptotic targets such as PUMA causing cancer cell death.

Original languageEnglish
Pages (from-to)762-776
Number of pages15
JournalApoptosis
Volume17
Issue number8
DOIs
Publication statusPublished - Aug 2012

Keywords

  • Apoptin
  • P73
  • PIR2
  • PUMA
  • RNF144B
  • Ubiquitin ligase E3

ASJC Scopus subject areas

  • Cell Biology
  • Clinical Biochemistry
  • Biochemistry, medical
  • Cancer Research
  • Pharmaceutical Science
  • Pharmacology

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    Taebunpakul, P., Sayan, B. S., Flinterman, M., Klanrit, P., Gäken, J., Odell, E. W., Melino, G., & Tavassoli, M. (2012). Apoptin induces apoptosis by changing the equilibrium between the stability of TAp73 and DNp73 isoforms through ubiquitin ligase PIR2. Apoptosis, 17(8), 762-776. https://doi.org/10.1007/s10495-012-0720-7