Recognition mechanism of p63 by the E3 ligase Itch: Novel strategy in the study and inhibition of this interaction

Alessia Bellomaria, Gaetano Barbato, Gerry Melino, Maurizio Paci, Sonia Melino

Research output: Contribution to journalArticlepeer-review


The HECT-containing E3 ubiquitin ligase Itch mediates the degradation of several proteins, including p63 and p73, involved in cell specification and fate. Itch contains four WW domains, which are essential for recognition on the target substrate, which contains a short proline-rich sequence. Several signaling complexes containing these domains have been associated with human diseases such as muscular dystrophy, Alzheimer's or Huntington's diseases. To gain further insight into the structural determinants of the Itch-WW2 domain, we investigated its interaction with p63. We assigned, by 3D heteronuclear NMR experiments, the backbone and side chains of the uniformly 13C-15N-labeled Itch-WW2. In vitro interaction of Itch-WW2 domain with p63 was studied using its interactive p63 peptide, pep63. Pep63 is an 18-mer peptide corresponding to the region from 534-551 residue of p63, encompassing the PPxY motif that interacts with the Itch-WW domains, and we identified the residues involved in this molecular recognition. Moreover, here, a strategy of stabilization of the conformation of the PPxY peptide has been adopted, increasing the WW-ligand binding. We demonstrated that cyclization of pep63 leads to an increase of both the biological stability of the peptide and of the WW-ligand complex. Stable metal-binding complexes of the pep63 have been also obtained, and localized oxidative damage on Itch-WW2 domain has been induced, demonstrating the possibility of use of metal-pep63 complexes as models for the design of metal drugs to inhibit the Itch-WW-p63 recognition in vivo. Thus, our data suggest a novel strategy to study and inhibit the recognition mechanism of Itch E3-ligase.

Original languageEnglish
Pages (from-to)3638-3648
Number of pages11
JournalCell Cycle
Issue number19
Publication statusPublished - Oct 1 2012


  • Cyclization
  • E3 ubiquitin ligases
  • HECT
  • Metal-peptide
  • P53 family
  • P63
  • Ubiquitilation

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology
  • Developmental Biology


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