Beta-1,4-glucuronyltransferase 1 (B4GAT1)

Beta-1,4-glucuronyltransferase 1 (B4GAT1) is a type II transmembrane glycosyltransferase localized primarily in the Golgi apparatus. Its key function is to transfer a glucuronic acid (GlcA) residue onto a xylose (Xyl) acceptor, producing a glucuronyl-beta-1,4-xylose disaccharide that serves as the critical primer for the extension of O-mannosyl glycans on alpha-dystroglycan by the glycosyltransferase LARGE. This priming event is essential for synthesizing the functional glycan required for alpha-dystroglycan's ligand-binding activity to extracellular matrix components such as laminin. Deficiencies in B4GAT1 result in impaired glycosylation of alpha-dystroglycan and lead to congenital muscular dystrophies collectively termed dystroglycanopathies, including Walker-Warburg syndrome. B4GAT1 was historically mis-annotated as a beta-1,3-N-acetylglucosaminyltransferase (B3GNT1/iGnT), but recent structural and enzymological studies have clarified its function as a glucuronyltransferase[1][2][3]. Notes: - No known small molecule drugs directly targeting B4GAT1 are reported in the literature. - Its role in disease is primarily as a genetic determinant rather than a druggable therapeutic target at present. - For patient stratification, B4GAT1 gene sequencing is used in the diagnostic workup of dystroglycanopathies.

Other names

B3GNT1B3GNT6iGnTIGnTiGATBETA3GNTIB3GN-T1I-beta-1,3-N-acetylglucosaminyltransferaseN-acetyllactosaminide beta-1,3-N-acetylglucosaminyltransferasePoly-N-acetyllactosaminide extension enzymeUDP-GlcNAc:betaGal beta-1,3-N-acetylglucosaminyltransferase 1UDP-GlcNAc:betaGal beta-1,3-N-acetylglucosaminyltransferase 6MDDGA13beta-1,3-N-acetylglucosaminyltransferase bGnT-6