Molecular basis of Pirh2-mediated p53 ubiquitylation.
Pirh2 (p53-induced RING-H2 domain protein; also known as Rchy1) is an E3 ubiquitin ligase involved in a negative-feedback loop with p53. Using NMR spectroscopy, we show that Pirh2 is a unique cysteine-rich protein comprising three modular domains. The protein binds nine zinc ions using a variety of zinc coordination schemes, including a RING domain and a left-handed beta-spiral in which three zinc ions align three consecutive small beta-sheets in an interleaved fashion. We show that Pirh2-p53 interaction is dependent on the C-terminal zinc binding module of Pirh2, which binds to the tetramerization domain of p53. As a result, Pirh2 preferentially ubiquitylates the tetrameric form of p53 in vitro and in vivo, suggesting that Pirh2 regulates protein turnover of the transcriptionally active form of p53.
Sheng
Yi
Y
Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto, Ontario M5G1L7, Canada.
Laister
Rob C
RC
Lemak
Alexander
A
Wu
Bin
B
Tai
Elizabeth
E
Duan
Shili
S
Lukin
Jonathan
J
Sunnerhagen
Maria
M
Srisailam
Sampath
S
Karra
Murthy
M
Benchimol
Sam
S
Arrowsmith
Cheryl H
CH
D000595:Amino Acid Sequence; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry* / Q000378:metabolism*; D054875:Ubiquitination
D016159:Tumor Suppressor Protein p53; C485369:RCHY1 protein, human; D044767:Ubiquitin-Protein Ligases