Ca2+-dependent interaction of recoverin with rhodopsin kinase

Ching Kang Chen, James Inglese, Robert J. Lefkowitz, James B. Hurley

Research output: Contribution to journalArticlepeer-review

268 Scopus citations

Abstract

Recoverin (Rv) is a myristoylated Ca2+-binding protein present primarily in bovine photoreceptors. It represents a newly identified family of neuronal specific Ca2+-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 Ca2+-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 Ca2+-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 μM. The N-terminal myristoyl residue of Rv enhances the inhibitory effect of Rv and introduces cooperativity to the Ca2+-dependent inhibition of rhodopsin phosphorylation. Rv neither interacts with other members of the G-protein-coupled receptor kinase family such as β-adrenergic receptor kinase 1 nor inhibits β-adrenergic receptor kinase 1 activity. The specific and Ca2+-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.

Original languageEnglish (US)
Pages (from-to)18060-18066
Number of pages7
JournalJournal of Biological Chemistry
Volume270
Issue number30
StatePublished - Jul 28 1995
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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