Agonist-dependent phosphorylation of the mouse delta-opioid receptor: involvement of G protein-coupled receptor kinases but not protein kinase C.

Published

Journal Article

With chronic opiate use, opioid receptor desensitization may be one of the important mechanisms underlying the development of opiate tolerance and addiction. Opioid receptors belong to the G protein-coupled receptor superfamily. In this study, the mouse delta-opioid receptor (delta OR) was used in a model system to investigate the role of opioid receptor phosphorylation in receptor desensitization. When expressed in 293 cells and exposed to agonist, the delta OR underwent receptor-specific desensitization within 10 min. This agonist-induced desensitization corresponded temporally to a 3-fold increase in receptor phosphorylation. Phorbol ester, but not forskolin, also stimulated phosphorylation of the delta OR in 293 cells. Although down-regulation of protein kinase C failed to affect agonist-induced receptor phosphorylation, it abolished phorbol ester-induced receptor phosphorylation. Agonist-induced delta OR phosphorylation must therefore involve kinases other than protein kinase C. Whereas overexpression of a dominant negative mutant (K220R) of beta-adrenergic receptor kinase-1 (beta ARK1) in 293 cells significantly reduced agonist-dependent phosphorylation of the delta OR, overexpression of beta ARK1 or G protein-coupled receptor kinase-5 significantly enhanced this phosphorylation. Concordantly, beta ARK1-K220R overexpression reduced agonist-dependent delta OR desensitization, whereas beta ARK1 overexpression enhanced this densensitization. We conclude that short term desensitization of the delta OR involves phosphorylation of the receptor by one or more G protein-coupled receptor kinases.

Full Text

Duke Authors

Cited Authors

  • Pei, G; Kieffer, BL; Lefkowitz, RJ; Freedman, NJ

Published Date

  • August 1995

Published In

Volume / Issue

  • 48 / 2

Start / End Page

  • 173 - 177

PubMed ID

  • 7651349

Pubmed Central ID

  • 7651349

International Standard Serial Number (ISSN)

  • 0026-895X

Language

  • eng

Conference Location

  • United States