Rhodopsin phosphorylation in bovine rod outer segments is more sensitive to the inhibitory action of recoverin at the low rhodopsin bleaching than it is at the high bleaching.
Recoverin, a calcium-binding protein, is supposed to have rhodopsin kinase as a target in the retinal rod cell. In the present work, we show that efficiency of recoverin as an inhibitor of rhodopsin phosphorylation in bovine rod outer segments is inversely proportional to the level of rhodopsin bleaching. These results, together with the data obtained previously in a reconstituted system (Senin et al. (1997) Biochem. J. 321, 551-555), allow us to hypothesize that recoverin might be responsible for a Ca2(+)-dependent regulation of the kinase in vivo, preventing it from participating in the phosphorylation of unbleached rhodopsin.
Senin
I I
II
Department of Enzymology, A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia.
Zargarov
A A
AA
Akhtar
M
M
Philippov
P P
PP
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000494:pharmacology*; D002417:Cattle; D003624:Darkness; D005136:Eye Proteins; D051606:G-Protein-Coupled Receptor Kinase 1; D051597:Hippocalcin; D007700:Kinetics; D008027:Light; D008074:Lipoproteins; D009419:Nerve Tissue Proteins; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology; D051603:Recoverin; D012243:Rhodopsin / Q000378:metabolism* / Q000528:radiation effects; D012374:Rod Cell Outer Segment / Q000378:metabolism*
D002135:Calcium-Binding Proteins; D005136:Eye Proteins; D008074:Lipoproteins; D009419:Nerve Tissue Proteins; D047428:Protein Kinase Inhibitors; D011994:Recombinant Proteins; D051603:Recoverin; D051597:Hippocalcin; D000255:Adenosine Triphosphate; D012243:Rhodopsin; D011494:Protein Kinases; D051606:G-Protein-Coupled Receptor Kinase 1; D002118:Calcium