LMPD Database

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LMP002186

UniProt Annotations

Entry Information
Gene NameUDP glucuronosyltransferase 1 family, polypeptide A3
Protein EntryUD13_HUMAN
UniProt IDP35503
SpeciesHuman
Comments
Comment typeDescription
Alternative ProductsEvent=Alternative splicing; Named isoforms=2; Name=1; Synonyms=i1; IsoId=P35503-1; Sequence=Displayed; Name=2; Synonyms=i2, UGT1A3s; IsoId=P35503-3; Sequence=VSP_053959;
Catalytic ActivityUDP-glucuronate + acceptor = UDP + acceptor beta-D-glucuronoside.
FunctionUDPGT is of major importance in the conjugation and subsequent elimination of potentially toxic xenobiotics and endogenous compounds. Isoform 2 lacks transferase activity but acts as a negative regulator of isoform 1.
MiscellaneousThe gene is part of the UGT1A complex locus which displays alternative use of promoters, first exons and terminal exons. The locus is defined by 13 first exons, which are alternatively spliced to 3 other common exons and 2 alternative terminal exons 5. From the 27 possible mRNA isoforms, 9 produce functionally active polypeptides (UGT1A1, 1A3, 1A4, 1A5, 1A6, 1A7, 1A8, 1A9 and 1A10) called isoforms 1 (i1). Use of an alternative exon 5 (5b) as terminal exon is leading to 9 additional alternatively spliced products termed isoforms i2 and which lack transferase activity.
SimilarityBelongs to the UDP-glycosyltransferase family.
Subcellular LocationMicrosome. Endoplasmic reticulum membrane {ECO
SubunitIsoform 1 interacts with isoform 2/i2 suggesting that oligomerization is involved in negative regulation of transferase activity by isoform 2. Isoform 1 also interacts with respective i2 isoforms of UGT1A1, UGT1A4, UGT1A6, UGT1A7, UGT1A8, UGT1A9 and UGT1A10.
Tissue SpecificityIsoform 1 and isoform 2 are expressed in liver, kidney, colon and small intestine. Isoform 1 but not isoform 2 is expressed in esophagus.