Beta-arrestin 2 functions as a G-protein-coupled receptor-activated regulator of oncoprotein Mdm2.

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.
Mesh Terms:
Animals, Apoptosis, Arrestins, Brain, Cell Line, DNA, Complementary, GTP-Binding Proteins, Gene Expression Regulation, Gene Library, Humans, Kidney, Mice, Nuclear Proteins, Proto-Oncogene Proteins, Proto-Oncogene Proteins c-mdm2, Receptors, Cell Surface, Recombinant Proteins, Transfection, Tumor Suppressor Protein p53, Ubiquitin
J. Biol. Chem.
Date: Feb. 21, 2003
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