β-Arrestin 2 Functions as a G-Protein-coupled Receptor-activated Regulator of Oncoprotein Mdm2

作者：Ping Wang, Hua Gao, Yanxiang Ni, Beibei Wang, Yalan Wu, Lili Ji, Lin-hua Qin, Lan Ma, Gang Pei · 发表于：Journal of Biological Chemistry · 年份：2003 · DOI：10.1074/jbc.m210350200 · 被引用次数：131 · 研究领域：Receptor Mechanisms and Signaling、Cancer, Stress, Anesthesia, and Immune Response、Protein Kinase Regulation and GTPase Signaling

Oncoprotein Mdm2 is a master negative regulator of the tumor suppressor p53 and has been recently shown to regulate the ubiquitination of beta-arrestin 2, an important adapter and scaffold in signaling of G-protein-coupled receptors (GPCRs). However, whether beta-arrestin 2 has any effect on the function of Mdm2 is still unclear. Our current results demonstrated that the binding of Mdm2 to beta-arrestin 2 was significantly enhanced by stimulation of GPCRs. Activation of GPCRs led to formation of a ternary complex of Mdm2, beta-arrestin 2, and GPCRs and thus recruited Mdm2 to GPCRs at plasma membrane. Moreover, the binding of beta-arrestin 2 to Mdm2 suppressed the self-ubiquitination of Mdm2 and consequently reduced the Mdm2-mediated p53 degradation and ubiquitination. Further experiments revealed that overexpression of beta-arrestin 2 enhanced the p53-mediated apoptosis while suppression of endogenous beta-arrestin 2 expression by RNA interference technology considerably attenuated the p53-mediated apoptosis. Our study thus suggests that beta-arrestin 2 may serve as a cross-talk linker between GPCR and p53 signaling pathways.