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retinal-specific ATP-binding cassette transporter; ATP-binding cassette sub-family A member 4; RIM ABC transporter; RIM protein; RmP; Stargardt disease protein (ABCA4 ABCR)

Function: - may play a role in photoresponse - retinoids, & most likely retinal, are natural substrates for transport by ABCR in rod outer segments - may act in the visual cycle to flip PE-all-trans-retinal adducts from the lumenal to the cytosolic face of the disk membrane, move free all-trans-retinal from the lipid phase of the disk membrane to a juxtamembrane location, or possibly reorient all-trans-retinal in the bilayer Structure: - belongs to the ABC transporter family, ABCA subfamily contains 2 ABC transporter domains Compartment: membrane Expression: - retinal-specific - exclusively found in rims of rod photoreceptor cells Polymorphism: 1) variant Ala-863 is present in the general population at a frequency of ~3% in Northern Europe & ~1% in United States - mild alteration probably leading to Stargardt disease phenotype only in combination with a more severe allele 2) the variant Glu-1961 is found in high frequency in healthy individuals of Somali ancestry Pathology: - defects in ABCA4 are the cause of a) Stargardt disease type 1 b) fundus flavimaculatus c) age-related macular degeneration type 2 d) cone-rod dystrophy type 3 e) retinitis pigmentosa 19

Related

ABCR gene Stargardt disease type 1 (STGD1)

General

ATP-binding cassette sub-family A (ABC transporter-A, ABCA)

Properties

SIZE: entity length = 2273 aa MW = 256 kD COMPARTMENT: cellular membrane MOTIF: N-glycosylation site {N14} transmembrane domain {22-42} N-glycosylation site {N98} N-glycosylation site {N415} N-glycosylation site {N444} N-glycosylation site {N504} transmembrane domain {547-567} transmembrane domain {647-667} transmembrane domain {700-720} transmembrane domain {731-751} transmembrane domain {760-780} transmembrane domain {836-856} ABC transporter 1 {929-1160} MOTIF: N-glycosylation site {N950} ATP-binding site NAME: ATP-binding site SITE: 963-970 transmembrane domain {1072-1092} transmembrane domain {1377-1397} N-glycosylation site {N1469} N-glycosylation site {N1529} transmembrane domain {1560-1580} N-glycosylation site {N1588} N-glycosylation site {N1662} transmembrane domain {1682-1702} N-glycosylation site {N1707} transmembrane domain {1728-1748} transmembrane domain {1760-1780} transmembrane domain {1793-1813} N-glycosylation site {N1819} transmembrane domain {1832-1852} transmembrane domain {1874-1894} N-glycosylation site {N1933} ABC transporter 2 {1938-2170} MOTIF: ATP-binding site NAME: ATP-binding site SITE: 1972-1979 N-glycosylation site {N2006} N-glycosylation site {N2052}

Database Correlations

OMIM correlations MORBIDMAP 601691 UniProt P78363 Pfam PF00005 Entrez Gene 24 Kegg hsa:24

References

  1. UniProt :accession P78363
  2. Mutations of the ABCA4 gene Retina International's Scientific Newsletter http://www.retina-international.com/sci-news/abcrmut.htm
  3. GeneReviews https://www.genecards.org/cgi-bin/carddisp.pl?gene=ABCA4