First Author | Wu X | Year | 2004 |
Journal | Mol Cell Biol | Volume | 24 |
Issue | 17 | Pages | 7748-57 |
PubMed ID | 15314180 | Mgi Jnum | J:92790 |
Mgi Id | MGI:3054509 | Doi | 10.1128/MCB.24.17.7748-7757.2004 |
Citation | Wu X, et al. (2004) Stabilization of the E3 ubiquitin ligase Nrdp1 by the deubiquitinating enzyme USP8. Mol Cell Biol 24(17):7748-57 |
abstractText | Nrdp1 is a RING finger-containing E3 ubiquitin ligase that physically interacts with and regulates steady-state cellular levels of the ErbB3 and ErbB4 receptor tyrosine kinases and has been implicated in the degradation of the inhibitor-of-apoptosis protein BRUCE. Here we demonstrate that the Nrdp1 protein undergoes efficient proteasome-dependent degradation and that mutations in its RING finger domain that disrupt ubiquitin ligase activity enhance stability. These observations suggest that Nrdp1 self-ubiquitination and stability could play an important role in regulating the activity of this protein. Using affinity chromatography, we identified the deubiquitinating enzyme USP8 (also called Ubpy) as a protein that physically interacts with Nrdp1. Nrdp1 and USP8 could be coimmunoprecipitated, and in transfected cells USP8 specifically bound to Nrdp1 but not cbl, a RING finger E3 ligase involved in ligand-stimulated epidermal growth factor receptor down-regulation. The USP8 rhodanese and catalytic domains mediated Nrdp1 binding. USP8 markedly enhanced the stability of Nrdp1, and a point mutant that disrupts USP8 catalytic activity destabilized endogenous Nrdp1. Our results indicate that Nrdp1 is a specific target for the USP8 deubiquitinating enzyme and are consistent with a model where USP8 augments Nrdp1 activity by mediating its stabilization. |