beta-arrestin-biased agonism at the beta2-adrenergic receptor.

Published

Journal Article

Classically, the beta 2-adrenergic receptor (beta 2AR) and other members of the seven-transmembrane receptor (7TMR) superfamily activate G protein-dependent signaling pathways in response to ligand stimulus. It has recently been discovered, however, that a number of 7TMRs, including beta 2AR, can signal via beta-arrestin-dependent pathways independent of G protein activation. It is currently unclear if among beta 2AR agonists there exist ligands that disproportionately signal via G proteins or beta-arrestins and are hence "biased." Using a variety of approaches that include highly sensitive fluorescence resonance energy transfer-based methodologies, including a novel assay for receptor internalization, we show that the majority of known beta 2AR agonists exhibit relative efficacies for beta-arrestin-associated activities (beta-arrestin membrane translocation and beta 2AR internalization) identical to the irrelative efficacies for G protein-dependent signaling (cyclic AMP generation). However, for three betaAR ligands there is a marked bias toward beta-arrestin signaling; these ligands stimulate beta-arrestin-dependent receptor activities to a much greater extent than would be expected given their efficacy for G protein-dependent activity. Structural comparison of these biased ligands reveals that all three are catecholamines containing an ethyl substitution on the alpha-carbon, a motif absent on all of the other, unbiased ligands tested. Thus, these studies demonstrate the potential for developing a novel class of 7TMR ligands with a distinct bias for beta-arrestin-mediated signaling.

Full Text

Duke Authors

Cited Authors

  • Drake, MT; Violin, JD; Whalen, EJ; Wisler, JW; Shenoy, SK; Lefkowitz, RJ

Published Date

  • February 29, 2008

Published In

Volume / Issue

  • 283 / 9

Start / End Page

  • 5669 - 5676

PubMed ID

  • 18086673

Pubmed Central ID

  • 18086673

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.M708118200

Language

  • eng

Conference Location

  • United States