RPE65: Plays important roles in the production of 11-cis retinal and in visual pigment regeneration. The soluble form binds vitamin A (all-trans-retinol), making it available for LRAT processing to all-trans-retinyl ester. The membrane form, palmitoylated by LRAT, binds all-trans-retinyl esters, making them available for IMH (isomerohydrolase) processing to all-cis- retinol. The soluble form is regenerated by transferring its palmitoyl groups onto 11-cis-retinol, a reaction catalyzed by LRAT. The enzymatic activity is linearly dependent of the expression levels and membrane association. Defects in RPE65 are the cause of Leber congenital amaurosis type 2 (LCA2). LCA designates a clinically and genetically heterogeneous group of childhood retinal degenerations, generally inherited in an autosomal recessive manner. Affected infants have little or no retinal photoreceptor function as tested by electroretinography. LCA represents the most common genetic cause of congenital visual impairment in infants and children. Defects in RPE65 are the cause of retinitis pigmentosa type 20 (RP20). RP leads to degeneration of retinal photoreceptor cells. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well. Defects in RPE65 are a cause of autosomal dominant retinitis pigmentosa with choroidal involvement (PubMed:21654732). Affected individuals show reduction of central vision, constriction of visual fields, night blindness and chorioretinal atrophy. Belongs to the carotenoid oxygenase family.
Protein type: EC 3.1.1.64; Cofactor and Vitamin Metabolism - retinol
Cellular Component: cytoplasm; endoplasmic reticulum; intracellular membrane-bound organelle; membrane; plasma membrane
Molecular Function: hydrolase activity; isomerase activity; metal ion binding; oxidoreductase activity, acting on single donors with incorporation of molecular oxygen, incorporation of two atoms of oxygen; retinal isomerase activity
Biological Process: detection of light stimulus involved in visual perception; insulin receptor signaling pathway; regulation of rhodopsin gene expression; response to stimulus; retina development in camera-type eye; retina morphogenesis in camera-type eye; retinal homeostasis; retinal metabolic process; retinol metabolic process; visual perception
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