G Protein-Coupled Receptor Kinase 2 Selectively Enhances β-Arrestin Recruitment to the D2 Dopamine Receptor through Mechanisms That Are Independent of Receptor Phosphorylation.
| Publication Type | Academic Article |
| Authors | Sánchez-Soto M, Boldizsar N, Schardien K, Madaras N, Willette B, Inbody L, Dasaro C, Moritz A, Drube J, Haider R, Free R, Hoffman C, Sibley D |
| Journal | Biomolecules |
| Volume | 13 |
| Issue | 10 |
| Date Published | 10/20/2023 |
| ISSN | 2218-273X |
| Keywords | G-Protein-Coupled Receptor Kinases, Receptors, Dopamine |
| Abstract | The D2 dopamine receptor (D2R) signals through both G proteins and β-arrestins to regulate important physiological processes, such as movement, reward circuitry, emotion, and cognition. β-arrestins are believed to interact with G protein-coupled receptors (GPCRs) at the phosphorylated C-terminal tail or intracellular loops. GPCR kinases (GRKs) are the primary drivers of GPCR phosphorylation, and for many receptors, receptor phosphorylation is indispensable for β-arrestin recruitment. However, GRK-mediated receptor phosphorylation is not required for β-arrestin recruitment to the D2R, and the role of GRKs in D2R-β-arrestin interactions remains largely unexplored. In this study, we used GRK knockout cells engineered using CRISPR-Cas9 technology to determine the extent to which β-arrestin recruitment to the D2R is GRK-dependent. Genetic elimination of all GRK expression decreased, but did not eliminate, agonist-stimulated β-arrestin recruitment to the D2R or its subsequent internalization. However, these processes were rescued upon the re-introduction of various GRK isoforms in the cells with GRK2/3 also enhancing dopamine potency. Further, treatment with compound 101, a pharmacological inhibitor of GRK2/3 isoforms, decreased β-arrestin recruitment and receptor internalization, highlighting the importance of this GRK subfamily for D2R-β-arrestin interactions. These results were recapitulated using a phosphorylation-deficient D2R mutant, emphasizing that GRKs can enhance β-arrestin recruitment and activation independently of receptor phosphorylation. |
| DOI | 10.3390/biom13101552 |
| PubMed ID | 37892234 |
| PubMed Central ID | PMC10605370 |