WWP2-WWP1 ubiquitin ligase complex coordinated by PPM1G maintains the balance between cellular p73 and ?Np73 levels.

ABSTRACT: The balance between transcription factor p73 and its functionally opposing N-terminally truncated ?Np73 isoform is critical for cell survival, but the precise mechanism that regulates their levels is not clear. In our study, we identified WWP2, an E3 ligase, as a novel p73-associated protein that ubiquitinates and degrades p73. In contrast, WWP2 heterodimerizes with another E3 ligase, WWP1, which specifically ubiquitinates and degrades ?Np73. Further, we identified phosphatase PPM1G as a functional switch that controls the balance between monomeric WWP2 and a WWP2/WWP1 heterodimeric state in the cell. During cellular stress, WWP2 is inactivated, leading to upregulation of p73, whereas WWP2-WWP1 complex is intact to degrade ?Np73, thus playing an important role in shifting the balance between p73 and ?Np73. Collectively, our results reveal a new functional E3 ligase complex controlled by PPM1G that differentially regulates cellular p73 and ?Np73.

SUBMITTER: Chaudhary N 

PROVIDER: S-EPMC4187731 | biostudies-literature | 2014 Oct

REPOSITORIES: biostudies-literature