title: Visual pigment phosphorylation but not transducin translocation can contribute to light adaptation in zebrafish cones.
abstract: The ability of cone photoreceptors to adapt to light is extraordinary. In this study we evaluated two biochemical processes, visual pigment phosphorylation and transducin translocation, for their ability to contribute to light adaptation in zebrafish cones. Since cytoplasmic Ca2+ regulates light adaptation, the sensitivities of these processes to both light and Ca2+ were examined. Cytoplasmic Ca2+ regulates the sites of light-stimulated phosphorylation. Unexpectedly, we found that Ca2+ also regulates the extent of phosphorylation of unbleached cone pigments. Immunocytochemical analyses revealed that neither light nor cytoplasmic Ca2+ influences the localization of transducin in zebrafish cones.
authors.affiliation: Department of Biochemistry, Box 357350, University of Washington, Seattle, WA 98195, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Kennedy
authors.forename: Felice A
authors.initials: FA
authors.lastname: Dunn
authors.forename: James B
authors.initials: JB
authors.lastname: Hurley
mesh_terms: D000221:Adaptation, Ocular / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D007150:Immunohistochemistry; D008027:Light; D009154:Mutation / Q000235:genetics; D009924:Organ Culture Techniques; D010766:Phosphorylation / Q000187:drug effects / Q000528:radiation effects; D010775:Photic Stimulation; D021381:Protein Transport / Q000502:physiology / Q000528:radiation effects; D017949:Retinal Cone Photoreceptor Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D012168:Retinal Pigments / Q000235:genetics / Q000378:metabolism*; D017299:Rod Opsins / Q000235:genetics / Q000378:metabolism; D015293:Transducin / Q000378:metabolism*; D014785:Vision, Ocular / Q000502:physiology* / Q000528:radiation effects; D015027:Zebrafish
chemical_list: D012168:Retinal Pigments; D017299:Rod Opsins; D015293:Transducin; D002118:Calcium