title: Distribution and translocation of photoreceptor Gbetagamma-phosducin system in medaka retina.
abstract: Unlike other vertebrates, teleosts have rod- and cone-specific phosducins (PD-R and PD-C) in the retina. To evaluate the teleost Gbetagamma-PD systems, we isolated cDNAs encoding medaka Gbeta1 and GbetaC, which selectively expressed rods and cones. Immunohistochemical studies showed that the strong reactivity of GbetaC but not PD-C was detected in cone outer segments. In rod outer segments (ROS), PD-R reactivity was stronger in light-adapted retina than in dark-adapted retina. Western blot analyses of fractions torn from the cryosections showed that the PD-R concentration was low in dark-adapted ROS. It is suggested that PD-R is translocated to ROS and effectively downregulates the phototransduction cascade in light-adapted rods.
authors.affiliation: Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan.
authors.forename: Shintaro
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Osamu
authors.initials: O
authors.lastname: Hisatomi
authors.forename: Akiyuki
authors.initials: A
authors.lastname: Hasegawa
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Fumio
authors.initials: F
authors.lastname: Tokunaga
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D015536:Down-Regulation; D005136:Eye Proteins / Q000378:metabolism*; D005399:Fishes; D020555:GTP-Binding Protein Regulators / Q000378:metabolism*; D044388:GTP-Binding Protein gamma Subunits / Q000737:chemistry / Q000378:metabolism*; D007150:Immunohistochemistry; D008027:Light; D008969:Molecular Sequence Data; D009990:Oryzias; D010750:Phosphoproteins / Q000378:metabolism*; D020419:Photoreceptor Cells, Vertebrate / Q000378:metabolism*; D012160:Retina / Q000378:metabolism*; D017949:Retinal Cone Photoreceptor Cells / Q000737:chemistry / Q000378:metabolism; D012374:Rod Cell Outer Segment / Q000737:chemistry / Q000378:metabolism; D014785:Vision, Ocular / Q000502:physiology
chemical_list: D005136:Eye Proteins; D020555:GTP-Binding Protein Regulators; D044388:GTP-Binding Protein gamma Subunits; D010750:Phosphoproteins; C065631:phosducin