The shorter wavelengths of the visible light have been recently reported to induce a long lasting hyperpigmentation but only in melano-competent individuals. Here, we provide evidence demonstrating that opsin 3 (OPN3) is the key sensor in melanocytes responsible for hyperpigmentation induced by the shorter wavelengths of the visible light. The melanogenesis induced through OPN3 is calcium-dependentand further activates CAMKII followed by CREB, ERK, and p38 leading to the phosphorylation of MITF and ultimately to the increase of the melanogenesis enzymes: tyrosinase and dopachrometautomerase(DCT). Furthermore, blue light induces the formation of a protein complex that we demonstrated to be formed by tyrosinase and DCT. This multimeric tyrosinase / Tyrp complex is mainly formed in dark-skinned melanocytes and induces a sustained tyrosinase activity, thus explaining the long-lasting hyperpigmentation that is observed only in skin type III and higher after blue light irradiation.OPN3 thus functions as the sensor for visible light pigmentation. OPN3 and the tyrosinase complex induced after its activation appear as new potential targets for regulating melanogenesis but also to protect dark skins against blue light in physiological conditions and in pigmentary disorders.

Melanocytes sense blue-light and regulate the pigmentation through the Opsin 3