Roles of acetylation and other post-translational modifications in melanocortin function and interactions with endorphins

Phylogenetic, developmental, anatomic, and stimulus-specific variations in post-translational processing of POMC are well established. For melanocortins, the role of α-N-acetylation and the selective activities of α, β, and γ forms are of special interest. Acetylation may shift the predominant activity of POMC products between endorphinergic and melanocortinergic actions—which are often in opposition. This review addresses: (1) variations in POMC processing; (2) the influence of acetylation on the functional activity of α-MSH; (3) state- and stimulus-dependent effects on the proportional distribution of forms of melanocortins and endorphins; (4) divergent effects of α-MSH and β-endorphin administration; (5) potential roles of β- and γ-MSH.