title: Does constitutive phosphorylation protect against photoreceptor degeneration in Rpe65-/- mice?
abstract: Despite the presence of this virgin opsin, Rpe65-/- rods are behaving like dark-adapted rods. These results argue that opsin which has not been exposed to 11-cis retinal and is constitutively phosphorylated, does not generate the activity generally associated with the bleached apoprotein. However, increased light-independent activation of transducin (due to bleached opsin) could be demonstrated after the addition of exogenous 11-cis retinal. We hypothesize that free opsin in the Rpe65-/- rods does not cause degeneration of rods by constitutive activation of the phototransduction cascade; but rather rods may die due to other causes such as the impairment of RPE function due to excess unprocessed retinyl-esters in the RPE.
authors.affiliation: Department of Ophthalmology, Medical University of South Carolina, Charleston, SC, USA. rohrer@musc.edu
authors.forename: Baerbel
authors.initials: B
authors.lastname: Rohrer
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Ablonczy
authors.forename: Sergei
authors.initials: S
authors.lastname: Znoiko
authors.forename: Michael
authors.initials: M
authors.lastname: Redmond
authors.forename: Jian-Xing
authors.initials: JX
authors.lastname: Ma
authors.forename: Rosalie
authors.initials: R
authors.lastname: Crouch
mesh_terms: D000818:Animals; D002352:Carrier Proteins; D004596:Electroretinography; D005136:Eye Proteins; D051379:Mice; D018345:Mice, Knockout / Q000235:genetics; D010766:Phosphorylation; D010786:Photoreceptor Cells / Q000473:pathology*; D011499:Protein Processing, Post-Translational; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D012160:Retina / Q000378:metabolism* / Q000503:physiopathology; D012162:Retinal Degeneration / Q000503:physiopathology / Q000517:prevention & control*; D017299:Rod Opsins / Q000235:genetics / Q000378:metabolism*; D019745:cis-trans-Isomerases; D000099178:Retinoid Isomerohydrolase
chemical_list: D002352:Carrier Proteins; D005136:Eye Proteins; D011506:Proteins; D017299:Rod Opsins; D019745:cis-trans-Isomerases; D000099178:Retinoid Isomerohydrolase