The F-box protein FBXO45 promotes the proteasome-dependent degradation of p73

A Peschiaroli, Flavia Scialpi, Francesca Bernassola, M Pagano, G Melino

Research output: Contribution to journalArticlepeer-review


The transcription factor p73, a member of the p53 family, mediates cell-cycle arrest and apoptosis in response to DNA damage-induced cellular stress, acting thus as a proapoptotic gene. Similar to p53, p73 activity is regulated by post-translational modification, including phosphorylation, acetylation and ubiquitylation. In C. elegans, the F-box protein FSN-1 controls germline apoptosis by regulating CEP-1, the single ancestral p53 family member. Here we report that FBXO45, the human ortholog of FSN-1, binds specifically to p73 triggering its proteasome-dependent degradation. Importantly, SCF(FBXO45) ubiquitylates p73 both in vivo and in vitro. Moreover, siRNA-mediated depletion of FBXO45 stabilizes p73 and concomitantly induces cell death in a p53-independent manner. All together, these results show that the orphan F-box protein FBXO45 regulates the stability of p73, highlighting a conserved pathway evolved from nematode to human by which the p53 members are regulated by an SCF-dependent mechanism.
Original languageEnglish
Pages (from-to)3157-66
Number of pages10
Issue number35
Publication statusPublished - 2009


  • ubiquitin
  • p73
  • Proteasome


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