1. β-arrestin2 plays permissive roles in the inhibitory activities of RGS9-2 on G protein-coupled receptors by maintaining RGS9-2 in the open conformation.
- Author
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Zheng M, Cheong SY, Min C, Jin M, Cho DI, and Kim KM
- Subjects
- Animals, Arrestins genetics, Brain metabolism, Cell Line, Tumor, Endocytosis, Gene Expression Regulation, HEK293 Cells, Humans, Immunoprecipitation, Mice, Plasmids, RNA, Small Interfering genetics, RNA, Small Interfering metabolism, Rats, Receptors, Dopamine D3 antagonists & inhibitors, Receptors, Dopamine D3 genetics, Receptors, Dopamine D3 metabolism, Signal Transduction, Transfection methods, beta-Arrestins, Arrestins metabolism, RGS Proteins genetics, RGS Proteins metabolism, Receptors, G-Protein-Coupled antagonists & inhibitors, Receptors, G-Protein-Coupled genetics
- Abstract
Together with G protein-coupled receptor (GPCR) kinases (GRKs) and β-arrestins, RGS proteins are the major family of molecules that control the signaling of GPCRs. The expression pattern of one of these RGS family members, RGS9-2, coincides with that of the dopamine D(3) receptor (D(3)R) in the brain, and in vivo studies have shown that RGS9-2 regulates the signaling of D2-like receptors. In this study, β-arrestin2 was found to be required for scaffolding of the intricate interactions among the dishevelled-EGL10-pleckstrin (DEP) domain of RGS9-2, Gβ5, R7-binding protein (R7BP), and D(3)R. The DEP domain of RGS9-2, under the permission of β-arrestin2, inhibited the signaling of D(3)R in collaboration with Gβ5. β-Arrestin2 competed with R7BP and Gβ5 so that RGS9-2 is placed in the cytosolic region in an open conformation which is able to inhibit the signaling of GPCRs. The affinity of the receptor protein for β-arrestin2 was a critical factor that determined the selectivity of RGS9-2 for the receptor it regulates. These results show that β-arrestins function not only as mediators of receptor-G protein uncoupling and initiators of receptor endocytosis but also as scaffolding proteins that control and coordinate the inhibitory effects of RGS proteins on the signaling of certain GPCRs.
- Published
- 2011
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