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MT000707

UniProt Annotations

Entry Information

Gene Name	ATP-binding cassette, sub-family G (WHITE), member 2 (Junior blood group)
Protein Entry	ABCG2_HUMAN
UniProt ID	Q9UNQ0
Species	Human

Comments

Comment type	Description
Alternative Products	Event=Alternative splicing; Named isoforms=2; Name=1; IsoId=Q9UNQ0-1; Sequence=Displayed; Name=2; IsoId=Q9UNQ0-2; Sequence=VSP_014232, VSP_014233; Note=No experimental confirmation available.;
Domain	The extracellular loop 3 (ECL3) is involved in binding porphyrins and transfer them to other carriers, probably albumin. {ECO:0000269\|PubMed:20705604}.
Function	High-capacity urate exporter functioning in both renal and extrarenal urate excretion. Plays a role in porphyrin homeostasis as it is able to mediates the export of protoporhyrin IX (PPIX) both from mitochondria to cytosol and from cytosol to extracellular space, and cellular export of hemin, and heme. Xenobiotic transporter that may play an important role in the exclusion of xenobiotics from the brain. Appears to play a major role in the multidrug resistance phenotype of several cancer cell lines. Implicated in the efflux of numerous drugs and xenobiotics: mitoxantrone, the photosensitizer pheophorbide, camptothecin, methotrexate, azidothymidine (AZT), and the anthracyclines daunorubicin and doxorubicin. {ECO:0000269\|PubMed:12958161, ECO:0000269\|PubMed:20705604, ECO:0000269\|PubMed:22132962, ECO:0000269\|PubMed:23189181}.
Induction	Up-regulated in brain tumors.
Interaction	P11309-1:PIM1; NbExp=9; IntAct=EBI-1569435, EBI-1018629; P0CG48:UBC; NbExp=2; IntAct=EBI-1569435, EBI-3390054;
Miscellaneous	When overexpressed, the transfected cells become resistant to mitoxantrone, daunorubicin and doxorubicin.
Polymorphism	Genetic variations in ABCG2 define the blood group Junior system (JR) [MIM:614490]. Individuals with Jr(a-) blood group lack the Jr(a) antigen on their red blood cells. These individuals may have anti-Jr(a) antibodies in their serum, which can cause transfusion reactions or hemolytic disease of the fetus or newborn. Although the clinical significance of the Jr(a-) blood group has been controversial, severe fatal hemolytic disease of the newborn has been reported. The Jr(a-) phenotype has a higher frequency in individuals of Asian descent, compared to those of European descent. The Jr(a-) phenotype is inherited as an autosomal recessive trait.
Polymorphism	Genetic variations in ABCG2 influence the variance in serum uric acid concentrations and define the serum uric acid concentration quantitative trait locus 1 (UAQTL1) [MIM:138900]. Excess serum accumulation of uric acid can lead to the development of gout, a common disorder characterized by tissue deposition of monosodium urate crystals as a consequence of hyperuricemia.
Ptm	Glycosylation-deficient ABCG2 is normally expressed and functional. {ECO:0000269\|PubMed:15807535}.
Sequence Caution	Sequence=AF093771; Type=Frameshift; Positions=486, 586; Evidence={ECO:0000305}; Sequence=AF093772; Type=Frameshift; Positions=386, 502, 586; Evidence={ECO:0000305};
Similarity	Belongs to the ABC transporter superfamily. ABCG family. Eye pigment precursor importer (TC 3.A.1.204) subfamily. {ECO:0000305}.
Similarity	Contains 1 ABC transmembrane type-2 domain. {ECO:0000305}.
Similarity	Contains 1 ABC transporter domain. {ECO:0000255\|PROSITE-ProRule:PRU00434}.
Subcellular Location	Cell membrane; Multi-pass membrane protein. Mitochondrion membrane; Multi-pass membrane protein.
Subunit	Monomer under reducing conditions, the minimal functional units is a homodimer; disulfide-linked, but the major oligomeric form in plasma membranes is a homotetramer with possibility of higher order oligomerization up to homododecamers. {ECO:0000269\|PubMed:15001581, ECO:0000269\|PubMed:17686774}.
Tissue Specificity	Highly expressed in placenta. Low expression in small intestine, liver and colon. {ECO:0000269\|PubMed:9850061, ECO:0000269\|PubMed:9861027}.
Web Resource	Name=ABCMdb; Note=Database for mutations in ABC proteins; URL="http://abcmutations.hegelab.org/proteinDetails?uniprot_id=Q9UNQ0";
Web Resource	Name=SeattleSNPs; URL="http://pga.gs.washington.edu/data/abcg2/";