RRH
Description
The RRH (retinal pigment epithelium-derived rhodopsin homolog) is a protein-coding gene located on chromosome 4.
Peropsin, a visual pigment-like receptor, is a protein encoded by the human RRH gene. Like other animal opsins, it belongs to the G protein-coupled receptor family. While discovered in mice and humans in 1997, much remains unknown about peropsins. Similar to most opsins, peropsins possess a lysine in their seventh transmembrane domain (corresponding to position 296 in cattle rhodopsin), crucial for retinal binding and light sensing. Interestingly, in amphioxus, a cephalochordate, peropsin binds all-trans-retinal in the dark state, unlike the 11-cis-retinal binding in cattle rhodopsin. This suggests peropsins may function as photoisomerases. In mice, peropsin is localized to the apical microvilli of the RPE, where it regulates vitamin A storage and movement between the retina and RPE. Peropsin is also expressed in human skin keratinocytes and responds to UV light in cell culture when retinal is supplied. In chickens, a peropsin is co-expressed with an RGR-opsin in the pineal gland and retina.
RRH is also known as -.
Associated Diseases
- Stargardt disease
- ovarian cancer
- congenital stationary night blindness
- retinitis pigmentosa
- retinal degeneration
- retinitis punctata albescens
