Light-dependent phosphorylation of rhodopsin by beta-adrenergic receptor kinase.

Published

Journal Article

The structural components involved in transduction of extracellular signals as diverse as a photon of light impinging on the retina or a hormone molecule impinging on a cell have been highly conserved. These components include a recognition unit or receptor (for example, the beta-adrenergic receptor (beta AR) for catecholamines or the 'light receptor' rhodopsin), a guanine nucleotide regulatory or transducing protein, and an effector enzyme (for example, adenylate cyclase or cyclic GMP phosphodiesterase). Molecular cloning has revealed that the beta AR shares significant sequence and three-dimensional homology with rhodopsin. The function of the beta AR is diminished by exposure to stimulatory agonists, leading to desensitization. Similarly, 'light adaptation' involves decreased coupling of photoactivated rhodopsin to cGMP phosphodiesterase activation. Both forms of desensitization involve receptor phosphorylation. The latter is mediated by a unique protein kinase, rhodopsin kinase, which phosphorylates only the light-bleached form of rhodopsin. An analogous enzyme (termed beta AR kinase or beta ARK) phosphorylates only the agonist-occupied beta AR. We report here that beta ARK is also capable of phosphorylating rhodopsin in a totally light-dependent fashion. Moreover, rhodopsin kinase can phosphorylate the agonist-occupied beta AR. Thus the mechanisms which regulate the function of these disparate signalling systems also appear to be similar.

Full Text

Duke Authors

Cited Authors

  • Benovic, JL; Mayor, F; Somers, RL; Caron, MG; Lefkowitz, RJ

Published Date

  • June 26, 1986

Published In

Volume / Issue

  • 321 / 6073

Start / End Page

  • 869 - 872

PubMed ID

  • 3014340

Pubmed Central ID

  • 3014340

International Standard Serial Number (ISSN)

  • 0028-0836

Digital Object Identifier (DOI)

  • 10.1038/321869a0

Language

  • eng

Conference Location

  • England