SLC45A2 is a transporter protein that mediates melanin synthesis. It may regulate the pH of the melanosome, affecting tyrosinase activity.[8] SLC45A2 is also a melanocyte differentiation antigen that is expressed in a high percentage of melanoma cell lines.[9] A similar sequence gene in medaka fish, 'B,' encodes a transporter that mediates melanin synthesis. Mutations in this gene are a cause of oculocutaneous albinism type 4. Alternative splicing results in multiple transcript variants encoding different isoforms.[7] Protein expression is localized to the melanosome, and analysis of the by knockdown of RNA expression leads to altered melanosome pH potentially altering tyrosinase function by affecting copper binding.[10]
In melanocytic cell types, the SLC45A2 gene is regulated by microphthalmia-associated transcription factor.[11][12]
SLC45A2 has been found to play a role in pigmentation in several species. In humans, it has been identified as a factor in the light skin of Europeans and as an ancestry-informative marker for distinguishing Sri Lankan from European ancestry.[13] Mutations in the gene have also been identified as the cause of human Type IV oculocutaneous albinism.[14] SLC45A2 is the so-called cream gene responsible in horses for buckskin, palomino and cremello coloration, while a mutation in this gene underlies the white tiger variant.[15] In dogs a mutation to this gene causes white fur, pink skin, and blue eyes.[16]
SLC45A2 was identified as a melanoma tumor-associated antigen with high tumor specificity and reduced potential for autoimmune toxicity, and is currently in clinical development as a target for T-cell based immunotherapy.[17]
