Visual arrestin binding to rhodopsin. Diverse functional roles of positively charged residues within the phosphorylation-recognition region of arrestin.
Arrestin plays a critical role in quenching phototransduction via its ability to specifically interact with the phosphorylated light-activated form of the visual receptor rhodopsin. In an effort to identify the residues involved in interaction with the phosphorylated C terminus of rhodopsin, we introduced point mutations into a basic region in visual arrestin previously implicated in phosphorylation-recognition (residues 163-189). A total of nine point mutations were made, each substituting a neutral hydrophilic residue for a positively charged Lys, Arg, or His. The functional consequences of these mutations were then analyzed by comparing the binding of full-length and truncated wild-type and mutant arrestin to various functional forms of rhodopsin. These studies demonstrate that Arg-171, Arg-175, and Lys-176 in bovine arrestin play a primary role in phosphate interaction, while Lys-166 and Lys-167 likely play a minor role in phosphate binding. In contrast, Lys-163 and His-179 appear to play a regulatory role, while Arg-182 and Arg-189 are not directly involved in arrestin binding to rhodopsin. Arg-175 also appears to function as a phosphorylation-sensitive trigger since charge neutralization by mutagenesis enables arrestin-R175N to bind to light-activated rhodopsin as well as wild-type arrestin binds to phosphorylated light-activated rhodopsin. The implications of these findings for the sequential multisite binding of arrestin to rhodopsin are discussed.
Gurevich
V V
VV
Department of Pharmacology, Jefferson Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Benovic
J L
JL
D000085:Acetates / Q000494:pharmacology; D019342:Acetic Acid; D000595:Amino Acid Sequence; D000818:Animals; D000941:Antigens / Q000096:biosynthesis / Q000737:chemistry* / Q000378:metabolism*; D019393:Arrestin; D001665:Binding Sites; D002417:Cattle; D005136:Eye Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010726:Phosphodiesterase Inhibitors / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation; D017354:Point Mutation; D014176:Protein Biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D015183:Restriction Mapping; D012243:Rhodopsin / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014158:Transcription, Genetic; D014785:Vision, Ocular
D000085:Acetates; D000941:Antigens; D019393:Arrestin; D005136:Eye Proteins; D010726:Phosphodiesterase Inhibitors; D011994:Recombinant Proteins; D012243:Rhodopsin; D019342:Acetic Acid