Mdm2 binds p73α without targeting degradation

The function of the p53 tumor suppressor protein is regulated by interaction with Mdm2, which targets p53 for ubiquitin dependent degradation. We show here that like p53, p73α forms an interaction with Mdm2, both in vitro and in cells, but this does not result in the degradation of the p73α protein. The human papillomavirus E6 protein also fails to degrade p73α, suggesting that the mechanisms governing p73α stability are distinct from those known to regulate p53 stability. However, the interaction of Mdm2 with 73α is sufficient to impede p73α transcriptional function, despite the lack of degradation.