N‐Myristoylation of recoverin enhances its efficiency as an inhibitor of rhodopsin kinase

FEBS Letters

Alekseev, Andrey M.¹  Senin, Ivan I.²  Zargarov, Aminullah A.¹  Philippov, Pavel P.²  Gorodovikova, Elena N.²  Lipkin, Valery M.¹ 

[1] Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Puschino, Moscow Region 142292, Russian Federation;Department of Enzymology, A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russian Federation

关键词: Photoreception;    Phosphorylation;    Rhodopsin;    Rhodopsin kinase;    Recoverin;    Calcium-binding protein;    Bovine retina rod cell;    ROS;    rod outer segment;    cGMP;    3′;    5′-cyclic guanosine monophosphate;    Rh;    rhodopsin;    RK;    rhodopsin kinase;    Rc;    recoverin;    m-Rc and n-Rc;    myristoylated and non-myristoylated recombinant recoverin;    respectively;   

DOI  :  10.1016/0014-5793(95)01187-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Recoverin, a recently identified member of the EF-hand superfamily of Ca²⁺-binding proteins, is capable to inhibit rhodopsin phosphorylation by rhodopsin kinase at high but not at low free [Ca²⁺]. The N-terminal glycine residue of retinal recoverin is heterogeneously acylated with myristoyl or related N-acyl group. To clarify the role of the N-terminal acylation of recoverin in its inhibitory action upon rhodopsin phosphorylation, we compared the efficiency of myristoylated and non-myristoylated forms of recombinant recoverin as inhibitors of rhodopsin kinase activity. We have found that rhodopsin phosphorylation by purified rhodopsin kinase, which does not depend on free [Ca²⁺] in the absence of recoverin, is regulated by Ca²⁺ in the presence of both forms of the recombinant protein. EC₅₀ values for Ca²⁺ are the same (2 μM) for the myristoylated and non-myristoylated forms; the Hill coefficients of 1.7 and 0.9, respectively, indicate that the effect is cooperative with respect to Ca²⁺ only for myristoylated recoverin. In the presence of Ca²⁺, both forms of recoverin taken at saturated concentrations cause an almost equal inhibition of rhodopsin phosphorylation. However, the inhibitory action of the myristoylated form occurs at much lower its concentrations than that of the non-myristoylated form (EC₅₀ are 0.9 and 6.5 μM, respectively).

【 授权许可】

Unknown