ASIP

Signaling protein that functions as an antagonist of melanocyte-stimulating-hormone receptor MC1R, thereby playing a role in the regulation of melanogenesis. Binding to MC1R prevents alpha-MSH-induced signaling and inhibits cAMP production, resulting in down-regulation of eumelanogenesis (brown/black pigment) and increased pheomelanin (yellow/red pigment) synthesis (By similarity). In higher primates, Agouti may affect the quality of hair pigmentation rather than the pattern of pigment deposition. May also play a role in neuroendocrine aspects of melanocortin action..

Function from UniProtKB (P42127), read 2026-09-23. CC BY 4.0.