Beta-1,3-glucuronyltransferase 1 (B3GAT1)

Beta-1,3-glucuronyltransferase 1 is an enzyme encoded by the B3GAT1 gene and is best known for synthesizing the CD57 (HNK-1/LEU7) carbohydrate epitope on glycoproteins. It is a key member of the glucuronyltransferase family and is involved in the biosynthesis of glycosaminoglycans and specialized carbohydrate epitopes important in the immune system and the nervous system. Its enzymatic activity is characterized by strict acceptor specificity for nonreducing terminal sugars. B3GAT1 plays an essential antiviral role by outcompeting sialyltransferases, preventing the display of sialic acid on the cell surface and thereby restricting entry of viruses such as influenza A, influenza B, and enterovirus D68. CD57/HNK-1 serves as a biomarker for certain immune cell populations and is also used as a marker in some cancers and chronic lymphoproliferative disorders. There are no drugs directly targeting B3GAT1 clinically, but it is an emerging potential host-directed antiviral target.

Other names

Galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase 1GLCATPGlcAT-PGlcUAT-PGlucuronosyltransferase PUDP-GlcUA:glycoprotein beta-1,3-glucuronyltransferaseCD57HNK1LEU7NK-1NK1LEU7 antigen

Not directly targeted by drugs; mechanism of antiviral action is via enzymatic addition of glucuronic acid to terminal carbohydrate residues, thereby blocking sialic acid–mediated viral entry