Contributes to a melanosome-specific anion (chloride) current that modulates melanosomal pH for optimal tyrosinase activity required for melanogenesis and the melanosome maturation. One of the components of the mammalian pigmentary system. May serve as a key control point at which ethnic skin color variation is determined. Major determinant of brown and/or blue eye color. Seems to regulate the post-translational processing of tyrosinase, which catalyzes the limiting reaction in melanin synthesis 