G-protein coupled receptor 143 (GPR143) is a receptor for tyrosine, L-DOPA and dopamine. After binding to L-DOPA, GPR143 stimulates Ca2+ influ, Xenopus/Amphibian, into the cytoplasm, increases secretion of the neurotrophic factor SERPINF1 and relocalizes beta arrestin at the plasma membrane. This ligand-dependent signaling occurs through a G(q)-mediated pathway in melanocytic cells. The activity of GPR143 is mediated by G proteins which activate the phosphoinositide signaling pathway. GPR143 also plays a role as an intracellular G protein-coupled receptor involved in melanosome biogenesis, organization and transport. Defects in GPR143 are the cause of albinism ocular type 1 (OA1), also known as Nettleship-Falls type ocular albinism. This is a form of albinism affecting only the eye. Pigment of the hair and skin is normal or only slightly diluted.