Oculocutaneous albinism II protein (OCA2)

Oculocutaneous albinism II protein (OCA2), also known as P protein or pink-eyed dilution protein homolog, is an integral membrane protein predominantly found in the melanosomal membrane of pigment-producing cells (melanocytes) and the retinal pigment epithelium[1][2][3][5]. OCA2 is predicted to function as a transporter—possibly a Na^+/dicarboxylate symporter or as part of a chloride channel—regulating the ionic environment and pH inside melanosomes to optimize melanin biosynthesis[1][3]. Defects or genetic mutations in OCA2 cause type II oculocutaneous albinism, the most common form of genetically inherited albinism, by impairing melanosome maturation, reducing melanin content, and leading to hypopigmentation of the skin, hair, and eyes as well as vision problems[1][3][4][5]. The protein contains twelve transmembrane helices and functions in the trafficking of other melanosomal proteins, likely through dileucine-based cytoplasmic motifs important for targeting to melanosomes and/or lysosomes[1][2][4]. OCA2 is not a primary therapeutic target nor does it have drugs known to directly interact with it, but mutation testing is a key diagnostic and prognostic biomarker in relevant pigmentation disorders[5].

Other names

P proteinPink-eyed dilution protein homologMelanocyte-specific transporter proteinEye color 2OCA2D15S12SLC13B1PEDSHEP1BOCABEY, BEY1, BEY2EYCL, EYCL2, EYCL3, HCL3

Not targeted by therapeutic drugs; Genetic mutations affect pigment biosynthesis by disrupting ion transport/chloride conductance[1][3]