AUTOPHOSPHORYLATION AND ADP REGULATE THE CA2-DEPENDENT INTERACTION OFRECOVERIN WITH RHODOPSIN KINASE()

Recoverin is a 23 kDa myristoylated Ca2+-binding protein that inhibits rhodopsin kinase. We have used surface plasmon resonance to investiga te the influences of Ca2+, myristoylation, and adenine nucleotides on the recoverin-rhodopsin kinase interaction. Our analyses confirmed tha t Ca2+ is required for recoverin to bind RK. Myristoylation had little effect on the affinity of recoverin for the kinase, but it raised the K0.5 for Ca2+ from 150 nM for nonacylated recoverin to 400 nM for myr istoylated recoverin. Finally, our studies also revealed two separate and previously unreported effects of adenine nucleotides on the recove rin-rhodopsin kinase binding. The interaction is weakened by autophosp horylation of the kinase, and it is strengthened by the presence of AD P.