title: Light-dependent translocation of arrestin in the absence of rhodopsin phosphorylation and transducin signaling.
abstract: Visual arrestin plays a crucial role in the termination of the light response in vertebrate photoreceptors by binding selectively to light-activated, phosphorylated rhodopsin. Arrestin localizes predominantly to the inner segments and perinuclear region of dark-adapted rod photoreceptors, whereas light induces redistribution of arrestin to the rod outer segments. The mechanism by which arrestin redistributes in response to light is not known, but it is thought to be associated with the ability of arrestin to bind photolyzed, phosphorylated rhodopsin in the outer segment. In this study, we show that light-driven translocation of arrestin is unaffected in two different mouse models in which rhodopsin phosphorylation is lacking. We further show that arrestin movement is initiated by rhodopsin but does not require transducin signaling. These results exclude passive diffusion and point toward active transport as the mechanism for light-dependent arrestin movement in rod photoreceptor cells.
authors.affiliation: Zilkha Neurogenetic Institute, The Mary D. Allen Laboratory for Vision Research, Beckman Macular Research Center, Doheny Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California 90089-2821, USA.
authors.forename: Ana
authors.initials: A
authors.lastname: Mendez
authors.forename: Janis
authors.initials: J
authors.lastname: Lem
authors.forename: Melvin
authors.initials: M
authors.lastname: Simon
authors.forename: Jeannie
authors.initials: J
authors.lastname: Chen
mesh_terms: D000818:Animals; D019393:Arrestin / Q000378:metabolism*; D001693:Biological Transport, Active / Q000528:radiation effects; D002352:Carrier Proteins; D005136:Eye Proteins; D008027:Light; D051379:Mice; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D010766:Phosphorylation; D021381:Protein Transport / Q000528:radiation effects; D011506:Proteins / Q000235:genetics; D017948:Retinal Rod Photoreceptor Cells / Q000378:metabolism / Q000528:radiation effects; D012243:Rhodopsin / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D012374:Rod Cell Outer Segment / Q000378:metabolism / Q000528:radiation effects; D015398:Signal Transduction / Q000502:physiology / Q000528:radiation effects*; D015293:Transducin / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D019745:cis-trans-Isomerases; D000099178:Retinoid Isomerohydrolase
chemical_list: D019393:Arrestin; D002352:Carrier Proteins; D005136:Eye Proteins; D011506:Proteins; D012243:Rhodopsin; D015293:Transducin; D019745:cis-trans-Isomerases; D000099178:Retinoid Isomerohydrolase