Membrane-associated transporter protein (MATP), also known as solute carrier family 45 member 2 (SLC45A2) or melanoma antigen AIM1, is a protein that in humans is encoded by the SLC45A2gene.[5][6][7]
In human, the SLC45A2 gene is located on the short (p) arm of chromosome 5 at position 13.2.
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]
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 (AIM) 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]
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See also
Evolution and divergence of light skin mutations and alleles. The SLC45A2 contributes to pigmentation in Europeans.Solute carrier family
