Tyrosinase: a central regulatory protein for cutaneous pigmentation.

Cutaneous pigmentation or skin color is the body's natural protection against sun-induced damage. Skin color is determined primarily by melanin, a biopolymer that is synthesized within epidermal melanocytes, packaged in cellular organelles called melanosomes, and then dispersed to neighboring keratinocytes. The process of melanogenesis involves numerous molecules and intracellular pathways that are subject to regulation by endogenous and exogenous factors. Tyrosinase is the central and rate-limiting enzyme in melanin biosynthesis. Therefore, elucidation of the molecules and pathways that regulate tyrosinase levels and activity could identify target areas for the development of compounds to decrease excessive pigmentation on one hand or induce pigmentation on the other. The following commentary will summarize the key regulatory molecules and pathways involved in tyrosinase function.