Agouti-signaling protein; ASP; Agouti switch protein (ASIP, AGTI, AGTIL, ASP)

Function

• role in the regulation of melanogenesis
• binding of ASP to MC1R precludes alpha-MSH initiated signaling & thus blocks production of cAMP, leading to a down-regulation of eumelanogenesis (brown/black pigment) & thus increasing synthesis of pheomelanin (yellow/red pigment)
• in higher primates, agouti may affect the quality of hair pigmentation rather than its pattern of deposition
• may play a role in neuroendocrine aspects of melanocortin action
• may have some functional role in regulating lipid metabolism with adipocytes

Structure

• the presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin
• contains 1 agouti domain

Compartment

secreted

Expression

• expressed in adipose tissue, testis, ovary & heart
• expressed at lower levels in liver, kidney & foreskin

Polymorphism

• genetic variations in ASIP are associated with variation in skin/hair/eye pigmentation type 9

More general terms

• secreted protein
• glycoprotein

Additional terms

• Agouti-related protein (AGRP AGRT ART)

Database

• UniProt: http://www.uniprot.org/uniprot/P42127.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=434
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:434
• OMIM: https://mirror.omim.org/entry/600201
• OMIM: https://mirror.omim.org/entry/611742