title: The E3 ubiquitin ligase Itch controls the protein stability of p63.
abstract: p63, a member of the p53 family of transcription factors, plays an important role in epithelial development, regulating both cell cycle and apoptosis. Even though p63 activity is regulated mainly at the posttranslational level, the control of p63 protein stability is far from being fully understood. Here, we show that the Hect (homologous to the E6-associated protein C terminus)-containing Nedd4-like ubiquitin protein ligase Itch binds, ubiquitylates, and promotes the degradation of p63. The physical interaction occurs at the border between the PY and the SAM (sterile alpha motif) domains; a single Y504F mutation significantly affects p63 degradation. Itch and p63 are coexpressed in the epidermis and in primary keratinocytes where Itch controls the p63 protein steady-state level. Accordingly, p63 protein levels are significantly increased in Itch knockout keratinocytes. These data suggest that Itch has a fundamental role in the mechanism that controls endogenous p63 protein levels and therefore contributes to regulation of p63 in physiological conditions.
authors.affiliation: Medical Research Council, Toxicology Unit, Leicester University, Leicester LE1 9HN, United Kingdom.
authors.forename: Mario
authors.initials: M
authors.lastname: Rossi
authors.forename: Rami I
authors.initials: RI
authors.lastname: Aqeilan
authors.forename: Michael
authors.initials: M
authors.lastname: Neale
authors.forename: Eleonora
authors.initials: E
authors.lastname: Candi
authors.forename: Paolo
authors.initials: P
authors.lastname: Salomoni
authors.forename: Richard A
authors.initials: RA
authors.lastname: Knight
authors.forename: Carlo M
authors.initials: CM
authors.lastname: Croce
authors.forename: Gerry
authors.initials: G
authors.lastname: Melino
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D006207:Half-Life; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D011485:Protein Binding; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*
chemical_list: D014157:Transcription Factors; D025801:Ubiquitin; D044767:Ubiquitin-Protein Ligases