G-protein coupled receptor which selectively activates G proteins via ultraviolet A (UVA) light-mediated activation in the skin. Binds both 11-cis retinal and all-trans retinal. Regulates melanogenesis in melanocytes via inhibition of alpha-MSH-induced MC1R-mediated cAMP signaling, modulation of calcium flux, regulation of CAMK2 phosphorylation, and subsequently phosphorylation of CREB, p38, ERK and MITF in response to blue light. Plays a role in melanocyte survival through regulation of intracellular calcium levels and subsequent BCL2/RAF1 signaling. Additionally regulates apoptosis via cytochrome c release and subsequent activation of the caspase cascade. Required for TYR and DCT blue light-induced complex formation in melanocytes. Involved in keratinocyte differentiation in response to blue-light. Required for the UVA-mediated induction of calcium and mitogen-activated protein kinase signaling resulting in the expression of MMP1, MMP2, MMP3, MMP9 and TIMP1 in dermal fibroblasts. Plays a role in light-mediated glucose uptake, mitochondrial respiration and fatty acid metabolism in brown adipocyte tissues. May be involved in photorelaxation of airway smooth muscle cells, via blue-light dependent GPCR signaling pathways.
