Tyrp1 and oculocutaneous albinism type 3

Tyrosinase-related protein 1 (Tyrp1) is a melanocyte-specific gene product involved in eumelanin synthesis. Mutations in the mouse Tyrp1 gene are associated with brown pelage, and in the human TYRP1 gene with oculocutaneous albinism type 3 (OCA3). In the murine system, Tyrp1 expresses significant dihydroxyindole carboxylic acid oxidase (i.e. DHICA oxidase) activity. However, in humans, TYRP1 is enigmatic in that despite extensive efforts focused on the study of its function, its actual role in the human melanocyte is still unclear. There is mounting evidence demonstrating that in addition to its role in eumelanin synthesis, Tyrp1 is involved in maintaining stability of tyrosinase protein and modulating its catalytic activity. Tyrp1 is also involved in maintenance of melanosome ultrastructure and affects melanocyte proliferation and melanocyte cell death. The current review is an attempt to consolidate our understanding of the role of Tyrp1 in the melanocyte.