Beta-1,3-galactosyltransferase 5 (B3GALT5)

Beta-1,3-galactosyltransferase 5 (B3GALT5) is a glycosyltransferase enzyme that catalyzes the transfer of galactose to N-acetylglucosamine, forming β1,3-linked galactosyl residues essential for the synthesis of type 1 glycan chains found in various Lewis-type antigens (e.g., sialyl Lewis a, CA19-9) and globo-series glycosphingolipids[1][3]. B3GALT5 is expressed in tissues such as the gastrointestinal tract, pancreas, liver, mammary gland, and is particularly enriched in colonic epithelial (goblet) cells[1][4]. It is an integral player in protein and lipid glycosylation, affecting cell adhesion, signaling, and the mucosal barrier. B3GALT5 is transcriptionally regulated by tissue-specific factors (e.g., Cdx, HNF1) and alternative promoters[1]. Pathologically, B3GALT5 is implicated in cancer biology: overexpression drives tumor progression and poor prognosis by promoting glycolysis via O-glycosylation of mTOR, thus enhancing tumor cell metabolism and survival[2][3]. Its role in maintaining the intestinal mucus barrier links it to metabolic and inflammatory diseases. B3GALT5 is under investigation as a prognostic marker and therapeutic target, though drugs directly targeting it remain experimental, with O-glycosylation inhibitors serving as proof of concept[2][3].

Other names

Beta-1,3-GalTase 5Beta3Gal-T5Beta3GalT5b3Gal-T5beta3Gal-T5B3GalT-VGLCT5B3T5Beta-3-Gx-T5UDP-Gal:beta-GlcNAc beta-1,3-galactosyltransferase 5UDP-galactose:beta-N-acetylglucosamine beta-1,3-galactosyltransferase 5homolog of C. elegans Bt toxin resistance gene bre-5GlcNAc-beta-1,3-galactosyltransferase 5B3GalTxbeta-1,3-GalTase 5beta-3-Gx-T5

Inhibition of O-linked glycosylation (e.g., benzyl-α-GalNAc reduces phosphorylated mTOR by disrupting O-glycosylation catalyzed by B3GALT5)