Synthesis of the all-trans-retinal chromophore of retinal G protein-coupled receptor opsin in cultured pigment epithelial cells
| Autor: | Henry K.W. Fong, Mao Yang |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Opsin
Rhodopsin genetic structures Biology Retinol dehydrogenase Biochemistry Models Biological Cell Line chemistry.chemical_compound Retinoids medicine Animals Humans Retinal G protein coupled receptor Pigment Epithelium of Eye Molecular Biology Cells Cultured Chromatography High Pressure Liquid Vision Ocular Retinal pigment epithelium Cell Membrane Rod Opsins Retinal Stereoisomerism Cell Biology eye diseases medicine.anatomical_structure chemistry Retinaldehyde biology.protein Cattle sense organs Visual phototransduction |
| Zdroj: | The Journal of biological chemistry. 277(5) |
| ISSN: | 0021-9258 |
| Popis: | Light-dependent production of 11-cis-retinal by the retinal pigment epithelium (RPE) and normal regeneration of rhodopsin under photic conditions involve the RPE retinal G protein-coupled receptor (RGR) opsin. This microsomal opsin is bound to all-trans-retinal which, upon illumination, isomerizes stereospecifically to the 11-cis isomer. In this paper, we investigate the synthesis of the all-trans-retinal chromophore of RGR in cultured ARPE-hRGR and freshly isolated bovine RPE cells. Exogenous all-trans-[(3)H]retinol is incorporated into intact RPE cells and converted mainly into retinyl esters and all-trans-retinal. The intracellular processing of all-trans-[(3)H]retinol results in physiological binding to RGR of a radiolabeled retinoid, identified as all-trans-[(3)H]retinal. The ARPE-hRGR cells contain a membrane-bound NADPH-dependent retinol dehydrogenase that reacts efficiently with all-trans-retinol but not the 11-cis isomer. The NADPH-dependent all-trans-retinol dehydrogenase activity in isolated RPE microsomal membranes can be linked in vitro to specific binding of the chromophore to RGR. These findings provide confirmation that RGR opsin binds the chromophore, all-trans-retinal, in the dark. A novel all-trans-retinol dehydrogenase exists in the RPE and performs a critical function in chromophore biosynthesis. |
| Databáze: | OpenAIRE |
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