The conversion of light into an electrical signal – and from there into vision – begins when a photon of light hits one of the “opsin” photoreceptors in the retina. These photoreceptors, including the well-studied rhodopsin, are members of the G-protein coupled receptor (GPCR) family of signaling proteins that are targets for about half of all drugs.
GPCR signaling is “turned off” in a two-step process culminating in arrestin binding. In rod cells, arrestin-1 binds to rhodopsin in various forms of its activation and “turn-off” cycle. Vsevolod Gurevich, Ph.D., professor of Pharmacology, Charles Sanders, Ph.D., professor of Biochemistry, and colleagues have now used solution NMR spectroscopy to explore the interaction of arrestin-1 with different forms of rhodopsin. In the Proceedings of the National Academy of Sciences, they report the affinity of arrestin-1 for different forms of rhodopsin and define the distinct elements involved in interaction.
The findings reveal the nature of receptor-induced structural changes in arrestins, which underlie the second round of GPCR signaling and can be targeted for therapeutic purposes.
This research was supported by grants from the National Institutes of Health (GM094608, GM080513, EY011500, GM077561, GM081756, GM095633, EY018435).