| First Author | Wenzel A | Year | 2005 |
| Journal | J Biol Chem | Volume | 280 |
| Issue | 33 | Pages | 29874-84 |
| PubMed ID | 15961402 | Mgi Jnum | J:101045 |
| Mgi Id | MGI:3590429 | Doi | 10.1074/jbc.M503603200 |
| Citation | Wenzel A, et al. (2005) The retinal G protein-coupled receptor (RGR) enhances isomerohydrolase activity independent of light. J Biol Chem 280(33):29874-84 |
| abstractText | Rod and cone visual pigments use 11-cis-retinal, a vitamin A derivative, as their chromophore. Light isomerizes 11-cis- into all-trans-retinal, triggering a conformational transition of the opsin molecule that initiates phototransduction. After bleaching all-trans-retinal leaves the opsin, and light sensitivity must be restored by regeneration of 11-cis-retinal. Under bright light conditions the retinal G protein-coupled receptor (RGR) was reported to support this regeneration by acting as a photoisomerase in a proposed photic visual cycle. We analyzed the contribution of RGR to rhodopsin regeneration under different light regimes and show that regeneration, during light exposure and in darkness, is slowed about 3-fold in Rgr(-/-) mice. These findings are not in line with the proposed function of RGR as a photoisomerase. Instead, RGR, independent of light, accelerates the conversion of retinyl esters to 11-cis-retinal by positively modulating isomerohydrolase activity, a key step in the 'classical' visual cycle. Furthermore, we find that light accelerates rhodopsin regeneration, independent of RGR. |
