A photic visual cycle of rhodopsin regeneration is dependent on Rgr

Nat Genet. 2001 Jul;28(3):256-60. doi: 10.1038/90089.


During visual excitation, rhodopsin undergoes photoactivation and bleaches to opsin and all-trans-retinal. To regenerate rhodopsin and maintain normal visual sensitivity, the all-trans isomer must be metabolized and reisomerized to produce the chromophore 11-cis-retinal in biochemical steps that constitute the visual cycle and involve the retinal pigment epithelium (RPE; refs. 3-8). A key step in the visual cycle is isomerization of an all-trans retinoid to 11-cis-retinol in the RPE (refs. 9-11). It could be that the retinochrome-like opsins, peropsin, or the retinal G protein-coupled receptor (RGR) opsin12-16 are isomerases in the RPE. In contrast to visual pigments, RGR is bound predominantly to endogenous all-trans-retinal, and irradiation of RGR in vitro results in stereospecific conversion of the bound all-trans isomer to 11-cis-retinal. Here we show that RGR is involved in the formation of 11-cis-retinal in mice and functions in a light-dependent pathway of the rod visual cycle. Mutations in the human gene encoding RGR are associated with retinitis pigmentosa.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Darkness
  • Dose-Response Relationship, Radiation
  • Electroretinography
  • Eye / metabolism*
  • Eye / radiation effects
  • Eye Proteins / genetics
  • Eye Proteins / metabolism*
  • Light
  • Mice
  • Mice, Mutant Strains
  • Models, Chemical
  • Photic Stimulation
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / metabolism*
  • Receptors, G-Protein-Coupled*
  • Retinal Rod Photoreceptor Cells / metabolism
  • Retinal Rod Photoreceptor Cells / radiation effects
  • Retinaldehyde / metabolism*
  • Rhodopsin / metabolism*
  • Rhodopsin / radiation effects


  • Eye Proteins
  • G protein-coupled receptor RGR
  • Receptors, Cell Surface
  • Receptors, G-Protein-Coupled
  • Rhodopsin
  • Retinaldehyde