title: Control of human PIRH2 protein stability: involvement of TIP60 and the proteosome.
abstract: Murine PIRH2 (mPIRH2) was recently identified as a RING finger-containing ubiquitin-protein isopeptide ligase that interacts with both p53 and the human androgen receptor. mpirh2 is a p53-responsive gene that is up-regulated by UV, and mPIRH2 protein has the capacity to polyubiquitylate p53, perhaps leading to p53 destruction. mpirh2 therefore has properties similar to those of the oncogene mdm2. Here, we have identified human PIRH2 (hPIRH2) as a TIP60-interacting protein. To investigate its regulation, we characterized hPIRH2 in parallel with hPIRH2 variants possessing mutations of conserved RING finger residues. We observed that wild-type hPIRH2 is an unstable protein with a short half-life and is a target for RING domain-dependent proteasomal degradation. Accordingly, we found that hPIRH2 was ubiquitylated in cells. The TIP60-hPIRH2 association appeared to regulate hPIRH2 stability; coexpression of TIP60 enhanced hPIRH2 protein stability and altered hPIRH2 subcellular localization. These results suggest that hPIRH2 activities can be controlled, at the post-translational level, in multiple ways.
authors.affiliation: Northern Institute for Cancer Research, School of Surgical and Reproductive Sciences, Medical School, University of Newcastle, Framlington Place, Newcastle upon Tyne NE2 4HH, United Kingdom.
authors.forename: Ian R
authors.initials: IR
authors.lastname: Logan
authors.forename: Vasileia
authors.initials: V
authors.lastname: Sapountzi
authors.forename: Luke
authors.initials: L
authors.lastname: Gaughan
authors.forename: David E
authors.initials: DE
authors.lastname: Neal
authors.forename: Craig N
authors.initials: CN
authors.lastname: Robson
mesh_terms: D000123:Acetyltransferases / Q000378:metabolism / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003546:Cysteine Endopeptidases / Q000378:metabolism / Q000502:physiology*; D017931:DNA Primers; D051548:Histone Acetyltransferases; D006801:Humans; D000074443:Lysine Acetyltransferase 5; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000378:metabolism / Q000502:physiology*; D046988:Proteasome Endopeptidase Complex; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D020798:Two-Hybrid System Techniques; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: D017931:DNA Primers; D009097:Multienzyme Complexes; D000123:Acetyltransferases; D051548:Histone Acetyltransferases; C098489:KAT5 protein, human; D000074443:Lysine Acetyltransferase 5; C485369:RCHY1 protein, human; D044767:Ubiquitin-Protein Ligases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex