title: A 49-kilodalton phosphoprotein in the Drosophila photoreceptor is an arrestin homolog.
abstract: The gene encoding the 49-kilodalton protein that undergoes light-induced phosphorylation in the Drosophila photoreceptor has been isolated and characterized. The encoded protein has 401 amino acid residues and a molecular mass of 44,972 daltons, and it shares approximately 42 percent amino acid sequence identity with arrestin (S-antigen), which has been proposed to quench the light-induced cascade of guanosine 3',5'-monophosphate hydrolysis in vertebrate photoreceptors. Unlike the 49-kilodalton protein, however, arrestin, which appears to bind to phosphorylated rhodopsin, has not itself been reported to undergo phosphorylation. In vitro, Ca2+ was the only agent found that would stimulate the phosphorylation of the 49-kilodalton protein. The phosphorylation of this arrestin-like protein in vivo may therefore be triggered by a Ca2+ signal that is likely to be regulated by light-activated phosphoinositide-specific phospholipase C.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City 73190.
authors.forename: T
authors.initials: T
authors.lastname: Yamada
authors.forename: Y
authors.initials: Y
authors.lastname: Takeuchi
authors.forename: N
authors.initials: N
authors.lastname: Komori
authors.forename: H
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Y
authors.initials: Y
authors.lastname: Sakai
authors.forename: Y
authors.initials: Y
authors.lastname: Hotta
authors.forename: H
authors.initials: H
authors.lastname: Matsumoto
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000941:Antigens; D019393:Arrestin; D001665:Binding Sites; D002118:Calcium / Q000494:pharmacology; D003001:Cloning, Molecular; D006152:Cyclic GMP / Q000378:metabolism; D004247:DNA / Q000235:genetics; D004331:Drosophila melanogaster / Q000235:genetics*; D004789:Enzyme Activation / Q000187:drug effects; D005136:Eye Proteins; D007526:Isoelectric Point; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D010766:Phosphorylation; D010786:Photoreceptor Cells / Q000032:analysis*; D014176:Protein Biosynthesis; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
chemical_list: D000941:Antigens; D019393:Arrestin; D005136:Eye Proteins; D010750:Phosphoproteins; D004247:DNA; D010727:Phosphoric Diester Hydrolases; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D006152:Cyclic GMP; D002118:Calcium