RCVRN:Ca2+ binds to and inhibits GRK1

Stable Identifier
Reaction [binding]
Homo sapiens
Ca2+ and recoverin restrict GRK1 activity
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A substantial fraction of rhodopsin kinase (GRK1) is bound to recoverin (RCVRN) in darkness, when internal Ca2+ levels are high. RCVRN is an EF-hand protein (Murakami et al. 1992) that functions as a myristoyl switch. With Ca2+ bound, the myristoyl group is exposed to attach RCVRN to the membrane. When Ca2+ levels drop with light exposure, Ca2+ dissociates from RCVRN and GRK1 is released. Higher levels of free GRK1 accelerate the phosphorylation and shutoff of photoexcited rhodopsin (MII). However, this feedback mechanism proceeds too slowly to impact the single photon response that was responsible for causing the fall in Ca2+. Instead, it operates during light adaptation, where the light-induced fall in Ca2+ primes the rod to release GRK1 to act after subsequent photoisomerizations of rhodopsin. RCVRN also serves as a Ca2+ buffer within the rod outer segment. Although mutations in RCVRN are not known to cause retinal disease, some cancer-associated retinopathies result from an autoimmune attack on RCVRN (Polans et al. 1991).
Literature References
PubMed ID Title Journal Year
1999465 A photoreceptor calcium binding protein is recognized by autoantibodies obtained from patients with cancer-associated retinopathy

Polans, AS, Crabb, J, BuczyƂko, J, Palczewski, K

J. Cell Biol. 1991
1387789 Isolation of human retinal genes: recoverin cDNA and gene

Inana, G, Murakami, A, Yajima, T

Biochem. Biophys. Res. Commun. 1992
Inferred From
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