Ubiquitin carboxyl-terminal hydrolase 5 (USP5)

Cleaves linear and branched multiubiquitin polymers with a marked taste for branched polymers. Involved in unanchored 'Lys-48'-linked polyubiquitin disassembly.

Binds linear and 'Lys- 63'-linked polyubiquitin with a lower affinity. Knock-down of USP5 induces the accumulation of p53/TP53 and an increase in p53/TP53 transcriptional activity because the unanchored polyubiquitin that accumulates is able to contend with ubiquitinated p53/TP53 but not with MDM2 for proteasomal recognition.