Opsin-3 (OPN3)

Opsin-3 (OPN3) is a nonvisual G protein-coupled receptor (GPCR) reportedly expressed in the brain, skin (particularly melanocytes), hypothalamus, adipose tissue, and other organs. OPN3 participates in diverse physiologic processes, notably functioning as a negative regulator of melanin production in human skin melanocytes by modulating melanocortin 1 receptor (MC1R) signaling in a light-independent manner through Gαi coupling. In the hypothalamus, OPN3 modulates energy balance and feeding behavior via interaction with melanocortin 4 receptor (MC4R) and Kir7.1 potassium channels. Although OPN3 is part of the opsin family (traditionally light-sensitive receptors), in humans it performs several important non-photoreceptive roles, and its precise light-responsiveness in vivo remains unclear. OPN3 is developmentally regulated, broadly expressed in neural tissues during embryogenesis, indicating additional potential roles in neurodevelopment and sensory system formation[1][2][3][4].

Other names

EncephalopsinPanopsinECPNERONMO-1PPP1R116protein phosphatase 1 regulatory subunit 116encephalopsinopsin 3 (encephalopsin, panopsin)

Negative regulation of cAMP signaling via Gαi protein in melanocytes; modulation of melanocortin receptor activity (MC1R in skin, MC4R in hypothalamus)