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P protein; melanocyte-specific transporter protein; pink-eyed dilution protein homolog (OCA2, D15S12, P)
Function:
- role in transport of tyrosine,precursor to melanin synthesis, within melanocytes (putative)
- regulates pH of melanosomes & melanosome maturation
- component of the mammalian pigmentary system
- appears to regulate post-translational processing of tyrosinase, which catalyzes the limiting step in melanin synthesis
- may serve as a key control point at which ethnic skin color variation is determined
- major determinant of brown &/or blue eye color
Structure:
- belongs to the SLC13A transporter (TC 2.A.47) family P subfamily
Compartment: melanosome membrane
Alternative splicing: named isoforms=3
Polymorphism:
- genetic variations in OCA2 are associated with skin/hair/eye pigmentation variability type 1
Pathology:
- defects in OCA2 are the cause of oculocutaneous albinism type 2
- the gene OCA2 is localized to chromosome 15 at 15q11.2-q12, a region associated with Prader-Willi & Angelman syndromes, suggesting that altered expression of the OCA2 gene may be responsible for the hypopygmentation phenotype exhibited by certain individuals with these disorders
- human pigmentation, including eye color, has been associated with skin cancer risk
Related
OCA2 gene mutation
General
carrier protein (transporter)
glycoprotein
transmembrane 12 protein
Properties
SIZE: entity length = 838 aa
MW = 93 kD
COMPARTMENT: cellular membrane
MOTIF: cytoplasmic domain {1-179}
transmembrane domain {180-197}
exoplasmic loop {198-330}
MOTIF: N-glycosylation site {N214}
N-glycosylation site {N218}
N-glycosylation site {N273}
transmembrane domain {331-347}
cytoplasmic loop {348-353}
transmembrane domain {354-370}
exoplasmic loop {371-384}
transmembrane domain {385-401}
cytoplasmic loop {402-423}
transmembrane domain {424-440}
exoplasmic loop {441-513}
MOTIF: N-glycosylation site {N442}
transmembrane domain {514-530}
cytoplasmic loop {531-620}
transmembrane domain {621-637}
exoplasmic loop {638-647}
transmembrane domain {648-664}
cytoplasmic loop {665-679}
transmembrane domain {680-696}
exoplasmic loop {697-720}
transmembrane domain {721-737}
cytoplasmic loop {738-760}
transmembrane domain {761-777}
exoplasmic loop {778-817}
MOTIF: N-glycosylation site {N781}
transmembrane domain {818-834}
cytoplasmic domain {835-838}
Database Correlations
OMIM correlations
MORBIDMAP 611409
UniProt Q04671
Pfam PF03600
Kegg hsa:4948
References
- UniProt :accession Q04671
- Mutations of the P gene
Retina International's Scientific newsletter
http://www.retina-international.com/sci-news/pgenemut.htm
- Albinism database (ADB); P mutations
http://albinismdb.med.umn.edu/oca2mut.html
- Protein Spotlight; Questioning colour -
Issue 54 of January 2005
http://www.expasy.org/spotlight/back_issues/sptlt054.shtml
- GeneReviews
https://www.genecards.org/cgi-bin/carddisp.pl?gene=OCA2