Title: Transcriptional Regulation of OCA2 and POMC by a cAMP-dependent mechanism and implications in skin pigmentation
Description: Skin Pigmentation represents the major natural protection against the deleterious effects of Ultraviolet light and involves a crosstalk between keratinocytes and melanocytes. Pigment synthesis or melanogenesis is initiated by the binding of alpha-Melanocyte Stimulating Hormone (alpha-MSH) to the Melanocortin 1 Receptor (MC1R), expressed by the melanocytes. alpha-MSH is generated by cleavage of pro-opiomelanocortin hormone (POMC), produced by both melanocytes and keratinocytes. Activation of MC1R leads to an increase in cAMP levels, causing the expression of the transcription factor MITF. MITF regulates the expression of the enzymes involved in melanogenesis as well as genes important for the survival and proliferation of melanocytes. Pigment synthesis, which occurs in specialized organelles called melanosomes, involves the regulation of different proteins as well as fine homeostatic tuning such as melanosomal pH regulation.