RPE-retinal G protein-coupled receptor is a protein that in humans is encoded by the RGRgene.
Defects in this gene are a cause of retinitis pigmentosa. The gene is a member of the rhodopsin-like receptor subfamily of GPCR. Like other opsins which bind retinaldehyde, it contains a conserved lysine residue in the seventh transmembrane domain. The protein presumably acts as a photoisomerase to catalyze the conversion of all-trans-retinal to 11-cis-retinal, similar to retinochrome in invertebrates. The reverse isomerization occurs with rhodopsin in retinal photoreceptor cells. The protein is exclusively expressed in tissue adjacent to retinal photoreceptor cells, the retinal pigment epithelium and Mueller cells. This gene may be associated with autosomal recessive and autosomal dominant retinitis pigmentosa (arRP and adRP, respectively). Alternative splicing results in multiple transcript variants encoding different isoforms.
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