Specific cGMP binding by retinal rod axoneme and its modulation by calcium ions and calmodulin.
The high-affinity binding of cGMP to the retinal rod axoneme was identified. The axoneme was shown to contain two types of binding sites, with concentrations of 3.6 X 10(-10) and 5.8 X 10(-11) mol mg protein-1. The cGMP concentration for half-saturation of binding was 0.35 microM. The inhibition of cGMP binding by colchicine and vinblastine was 20% of Ca2+ and calmodulin control cGMP binding. The effect of calmodulin is explained by its interaction with specific binding sites which are possibly associated with Ca(2+)-induced depolymerization of axoneme microtubules.
Volotovsky
I D
ID
Institute of Photobiology, Byelorussian SSR Academy of Sciences, Minsk U.S.S.R.
Baranova
L A
LA
Khovratovich
V I
VI
D000818:Animals; D002118:Calcium / Q000502:physiology*; D002147:Calmodulin / Q000502:physiology*; D002417:Cattle; D046508:Culture Techniques; D006152:Cyclic GMP / Q000378:metabolism*; D008027:Light; D012374:Rod Cell Outer Segment / Q000378:metabolism*
D002147:Calmodulin; D006152:Cyclic GMP; D002118:Calcium