Arrestin-rhodopsin interaction. Multi-site binding delineated by peptide inhibition.

摘要: Visual arrestin modulates the intracellular response of retinal rod cells to light by specifically binding phosphorylated light-activated form photoreceptor rhodopsin (P-Rh*). In order characterize molecular interaction between and arrestin, we have studied ability synthetic peptides from proposed cytoplasmic loops inhibit binding. A third loop peptide competed most effectively for P-Rh*, exhibiting an IC50 34 microM, while a first weakly inhibited with approximately 1100 microM. The also P-Rh* both ARR[delta (2-16)-404], mutant that lacks residues 2-16, ARR[1-191], contains only amino half arrestin. However, had 5-fold lower affinity at inhibiting ARR[1-191] P-Rh*. While truncated lacking its C-terminal sites phosphorylation, modestly enhanced dark rhodopsin. These results suggest and, lesser extent, may play important role in forms