Figure 1.

Pigmentary pathway of MC1R. Binding of α-MSH on MC1R receptor activates adenylyl cyclase (AC) and stimulates cAMP production, which in turns induce the activation of several downstream effectors, including MITF transcription factor. MITF binds the MBOX on the promoters of tyrosinase (TYR), phosphoribosylanthranilate isomerase (TRP1) and dopachrome tautomerase (DCT) genes, leading to the expression of different enzymes involved in melanin biosynthesis. Melanin acts as a UV-protective shield in the epidermis. (Gα-β-γ proteins, CREB (cAMP response element binding protein), CBP (CREB-binding protein), CRE (cAMP response elements), c-KIT (tyrosine-protein kinase KIT), SH2 (Src homology 2), GEF (Guanine nucleotide Exchange Factor), MAPK/ERK (extracellular signal-regulated kinases)). This figure was created with BioRender.com.