Identification of a single phosphorylation site within octopus rhodopsin

Light-dependent phosphorylation of rhodopsin (Rho) is a first step in the d esensitization of the signaling state of the receptor during vertebrate and invertebrate visual transduction, We found that only (358)Ser of the photo activated octopus Rho (oRho*) was phosphorylated by octopus rhodopsin kinas e (oRK), Tryptic truncation of the C-terminal PPQGY repeats of oRho that fo llow the phosphorylation region did not influence spectral or G-protein act ivation properties of oRho but abolished phosphorylation, Despite significa nt structural differences between oRK and mammalian RK, these results provi de further evidence of the importance of singly phosphorylated species of R ho* in the generation of arrestin binding sites.