Molecular basis of Pirh2-mediated p53 ubiquitylation

Pirh2 is one of several ubiquitin ligases known to modify and negatively regulate p53. Solution studies reveal the structures of the three Pirh2 domains and indicate that the C-terminal domain of Pirh2 interacts with the p53 tetramerization domain. Additional data suggest that Pirh2 preferentially modifies the tetrameric, transcriptionally active form of p53 for proteasome-mediated degradation.