| Scientific Background: | The melanocortin receptors are members of the G protein-coupled receptor superfamily. Their ligands, the melanocortins, are peptides consisting of a-, b- and g-melanocyte stimulating hormone and adrenocorticotropic hormone. MC1R was the first member of the melanocortin receptor family to be cloned. The receptor transduces signals via Gs resulting in the activation of adenylate cyclase and production of cAMP. MC1R can be described as the “classical” melanocyte a-MSH receptor. The receptor is expressed in the skin where it has a key role in determining skin and hair pigmentation. In fur-bearing mammals, the local ratio between a-MSH and agouti determines coat pigmentation as a-MSH stimulates and agouti inhibits melanin production. MC1R expression in melanoma cells is up-regulated up to 20-fold compared to normal melanocytes. |
