Melanocortin Type 1 Receptor (MC1R)

The Melanocortin Type 1 Receptor (MC1R) is a G protein-coupled receptor primarily expressed on melanocytes, playing a key role in regulating skin and hair pigmentation. Upon activation by agonists like α-MSH, MC1R stimulates eumelanin production, providing photoprotection. Loss-of-function variants are associated with fair skin, red hair, and increased melanoma risk. Beyond pigmentation, MC1R is also involved in immune modulation and DNA repair. The agouti signaling protein acts as an antagonist. Drugs like afamelanotide are used therapeutically.

Other names

Melanocyte-stimulating hormone receptorMSHRMelanin-activating peptide receptorMelanotropin receptor

Agonist binding activates adenylyl cyclase, increasing cAMP levels and promoting eumelanin synthesis and DNA repair. Antagonists inhibit this pathway, favoring pheomelanin synthesis.