CALCIUM CALMODULIN-DEPENDENT PROTEIN-KINASE-II AND ARRESTIN PHOSPHORYLATION IN LIMULUS EYES/

In rhabdomeral photoreceptors, light stimulates the phosphorylation of arrestin, a protein critical for quenching the photoresponse, by acti vating a calcium/calmodulin-dependent protein kinase (CaM PK). Here we present biochemical evidence that a CaM PK that phosphorylates arrest in in Limulus eyes is structurally similar to mammalian CaM PK II. In addition, cDNAs encoding proteins homologous to mammalian and Drosophi la CaM PK II in the catalytic and regulatory domains were cloned and s equenced from a Limulus lateral eye cDNA library. The Limulus sequence s are unique, however, in that they lack most of the association domai n. The proteins encoded by these sequences may phosphorylate arrestin.