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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
Related
Agouti-related protein (AGRP AGRT ART)
General
glycoprotein
secreted protein
Properties
SIZE: entity length = 132 aa
MW = 15 kD
COMPARTMENT: extracellular compartment
MOTIF: signal sequence {1-22}
N-glycosylation site {N39}
lysine-rich region {57-86}
MOTIF: lysine residue (SEVERAL)
Agouti {93-132}
MOTIF: cysteine residue {C93}
MODIFICATION: cysteine residue {C108}
cysteine residue {C100}
MODIFICATION: cysteine residue {C114}
cysteine residue {C107}
MODIFICATION: cysteine residue {C125}
cysteine residue {C108}
MODIFICATION: cysteine residue {C93}
cysteine residue {C111}
MODIFICATION: cysteine residue {C132}
cysteine residue {C114}
MODIFICATION: cysteine residue {C100}
cysteine residue {C116}
MODIFICATION: cysteine residue {C123}
cysteine residue {C123}
MODIFICATION: cysteine residue {C116}
cysteine residue {C125}
MODIFICATION: cysteine residue {C107}
cysteine residue {C132}
MODIFICATION: cysteine residue {C111}
Database Correlations
OMIM correlations
UniProt P42127
Pfam PF05039
Entrez Gene 434
Kegg hsa:434
References
- UniProt :accession P42127
- Entrez Gene :accession 434