G-protein-coupled receptor kinase specificity for beta-arrestin recruitment to the beta2-adrenergic receptor revealed by fluorescence resonance energy transfer.

Journal Article

The small family of G-protein-coupled receptor kinases (GRKs) regulate cell signaling by phosphorylating heptahelical receptors, thereby promoting receptor interaction with beta-arrestins. This switches a receptor from G-protein activation to G-protein desensitization, receptor internalization, and beta-arrestin-dependent signal activation. However, the specificity of GRKs for recruiting beta-arrestins to specific receptors has not been elucidated. Here we use the beta(2)-adrenergic receptor (beta(2)AR), the archetypal nonvisual heptahelical receptor, as a model to test functional GRK specificity. We monitor endogenous GRK activity with a fluorescence resonance energy transfer assay in live cells by measuring kinetics of the interaction between the beta(2)AR and beta-arrestins. We show that beta(2)AR phosphorylation is required for high affinity beta-arrestin binding, and we use small interfering RNA silencing to show that HEK-293 and U2-OS cells use different subsets of their expressed GRKs to promote beta-arrestin recruitment, with significant GRK redundancy evident in both cell types. Surprisingly, the GRK specificity for beta-arrestin recruitment does not correlate with that for bulk receptor phosphorylation, indicating that beta-arrestin recruitment is specific for a subset of receptor phosphorylations on specific sites. Moreover, multiple members of the GRK family are able to phosphorylate the beta(2)AR and induce beta-arrestin recruitment, with their relative contributions largely determined by their relative expression levels. Because GRK isoforms vary in their regulation, this partially redundant system ensures beta-arrestin recruitment while providing the opportunity for tissue-specific regulation of the rate of beta-arrestin recruitment.

Full Text

Duke Authors

Cited Authors

  • Violin, JD; Ren, X-R; Lefkowitz, RJ

Published Date

  • July 21, 2006

Published In

Volume / Issue

  • 281 / 29

Start / End Page

  • 20577 - 20588

PubMed ID

  • 16687412

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.M513605200

Language

  • eng

Conference Location

  • United States