TYRP2

TYRP2, also known as dopachrome tautomerase (DCT), is a member of the tyrosinase-related protein family that participates in melanin biosynthesis in pigment cells. It is involved in the melanogenic pathway within melanosomes, the organelles where melanin synthesis occurs.

The enzyme catalyzes the tautomerization of dopachrome to DHICA (5,6-dihydroxyindole-2-carboxylic acid), a downstream intermediate in eumelanin production. This activity helps determine the balance of eumelanin synthesis and contributes to the overall pigmentation of skin, hair, and other pigmented tissues. TYRP2 operates in concert with other melanogenic enzymes, particularly TYR (tyrosinase) and TYRP1, and participates in the melanosome-associated enzyme complex that coordinates melanin production and organelle maturation.

Expression of TYRP2 is highest in melanocytes of the skin and hair follicles and in the retinal pigment epithelium, with tissue- and species-specific variation. The protein is part of the secretory pathway and is associated with melanosomes, where it functions alongside related enzymes.

Genetic and clinical aspects: pathogenic variants in TYRP2 have been described in rare instances of pigmentary disorders, including oculocutaneous albinism in some reports, but TYRP2 is not among the major genes commonly implicated in albinism. In animal models, loss of TYRP2 function produces lighter coat color and reduced melanin, supporting its role in pigmentation. Beyond disease associations, TYRP2 has been studied for its potential links to human skin color variation and melanoma biology, though findings are not yet definitive.