Manifold roles of β-arrestins in GPCR signaling elucidated with siRNA and CRISPR/Cas9.

Published

Journal Article

G protein-coupled receptors (GPCRs) use diverse mechanisms to regulate the mitogen-activated protein kinases ERK1/2. β-Arrestins (βArr1/2) are ubiquitous inhibitors of G protein signaling, promoting GPCR desensitization and internalization and serving as scaffolds for ERK1/2 activation. Studies using CRISPR/Cas9 to delete βArr1/2 and G proteins have cast doubt on the role of β-arrestins in activating specific pools of ERK1/2. We compared the effects of siRNA-mediated knockdown of βArr1/2 and reconstitution with βArr1/2 in three different parental and CRISPR-derived βArr1/2 knockout HEK293 cell pairs to assess the effect of βArr1/2 deletion on ERK1/2 activation by four Gs-coupled GPCRs. In all parental lines with all receptors, ERK1/2 stimulation was reduced by siRNAs specific for βArr2 or βArr1/2. In contrast, variable effects were observed with CRISPR-derived cell lines both between different lines and with activation of different receptors. For β2 adrenergic receptors (β2ARs) and β1ARs, βArr1/2 deletion increased, decreased, or had no effect on isoproterenol-stimulated ERK1/2 activation in different CRISPR clones. ERK1/2 activation by the vasopressin V2 and follicle-stimulating hormone receptors was reduced in these cells but was enhanced by reconstitution with βArr1/2. Loss of desensitization and receptor internalization in CRISPR βArr1/2 knockout cells caused β2AR-mediated stimulation of ERK1/2 to become more dependent on G proteins, which was reversed by reintroducing βArr1/2. These data suggest that βArr1/2 function as a regulatory hub, determining the balance between mechanistically different pathways that result in activation of ERK1/2, and caution against extrapolating results obtained from βArr1/2- or G protein-deleted cells to GPCR behavior in native systems.

Full Text

Duke Authors

Cited Authors

  • Luttrell, LM; Wang, J; Plouffe, B; Smith, JS; Yamani, L; Kaur, S; Jean-Charles, P-Y; Gauthier, C; Lee, M-H; Pani, B; Kim, J; Ahn, S; Rajagopal, S; Reiter, E; Bouvier, M; Shenoy, SK; Laporte, SA; Rockman, HA; Lefkowitz, RJ

Published Date

  • September 25, 2018

Published In

Volume / Issue

  • 11 / 549

PubMed ID

  • 30254056

Pubmed Central ID

  • 30254056

Electronic International Standard Serial Number (EISSN)

  • 1937-9145

International Standard Serial Number (ISSN)

  • 1945-0877

Digital Object Identifier (DOI)

  • 10.1126/scisignal.aat7650

Language

  • eng