Ca(2+)-dependent interaction of recoverin with rhodopsin kinase.

Published

Journal Article

Recoverin (Rv) is a myristoylated Ca(2+)-binding protein present primarily in bovine photoreceptors. It represents a newly identified family of neuronal specific Ca(2+)-binding proteins that includes neurocalcin, hippocalcin, and guanylyl cyclase-activating protein. To investigate the function of Rv in photoreceptors, we identified proteins that bind immobilized Rv in a Ca(2+)-dependent manner. Rhodopsin kinase (RK), interphotoreceptor retinoid-binding protein, and tubulin interact with Rv in the presence of Ca2+. The importance of the Rv/RK interaction was further characterized. RK, purified using immobilized Rv as an affinity matrix, catalyzed the light-dependent and Ca(2+)-independent incorporation of phosphates into rhodopsin when reconstituted with urea-stripped rod outer segment membranes. When only a small fraction (0.04%) of rhodopsin was photolyzed, as many as 700 phosphates were incorporated per photolyzed rhodopsin, a phenomenon known as "high gain" phosphorylation. When recoverin was added, the activity of RK became sensitive to free Ca2+, with EC50 = 3 microM. The N-terminal myristoyl residue of Rv enhances the inhibitory effect of Rv and introduces cooperativity to the Ca(2+)-dependent inhibition of rhodopsin phosphorylation. Rv neither interacts with other members of the G-protein-coupled receptor kinase family such as beta-adrenergic receptor kinase 1 nor inhibits beta-adrenergic receptor kinase 1 activity. The specific and Ca(2+)-dependent Rv/RK interaction is necessary for the inhibitory effect of Rv on rhodopsin phosphorylation and may play an important role in photoreceptor light adaptation.

Full Text

Duke Authors

Cited Authors

  • Chen, CK; Inglese, J; Lefkowitz, RJ; Hurley, JB

Published Date

  • July 28, 1995

Published In

Volume / Issue

  • 270 / 30

Start / End Page

  • 18060 - 18066

PubMed ID

  • 7629115

Pubmed Central ID

  • 7629115

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.270.30.18060

Language

  • eng

Conference Location

  • United States