Stabilization of the E3 Ubiquitin Ligase Nrdp1 by the Deubiquitinating Enzyme USP8

Autor: Xiuli Wu, Kermit L. Carraway, Colleen A Sweeney, Lisa Irwin, Lily Yen
Rok vydání: 2004
Předmět:
Zdroj: Wu, Xiuli; Yen, Lily; Irwin, Lisa; Sweeney, Colleen; & Carraway, Kermit L. (2004). Stabilization of the E3 ubiquitin ligase Nrdp1 by the deubiquitinating enzyme USP8. Molecular and Cellular Biology, 24(17), 7748-7757. UC Davis: Retrieved from: http://www.escholarship.org/uc/item/3xq0b1j0
ISSN: 1098-5549
DOI: 10.1128/mcb.24.17.7748-7757.2004
Popis: 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.
Databáze: OpenAIRE