Alpha-1,3-mannosyl-glycoprotein 4-beta-N-acetylglucosaminyltransferase B (MGAT4B)

Alpha-1,3-mannosyl-glycoprotein 4-beta-N-acetylglucosaminyltransferase B (MGAT4B) is a key enzyme involved in the biosynthesis of branched N-glycans within the Golgi apparatus[1][2][5]. It catalyzes the transfer of N-acetylglucosamine (GlcNAc) from UDP-GlcNAc to the core mannose of N-linked glycoproteins, facilitating the formation of tri- and tetra-antennary glycan structures[1][2]. MGAT4B works in concert with the closely related enzyme MGAT4A but has lower substrate affinities and is not the main contributor to overall N-glycan branching under physiological conditions[1][2]. MGAT4B is essential for proper glycoprotein processing, has been linked to congenital disorders of glycosylation and certain cancers (notably pancreatic), and may influence serum glycoprotein levels as well as cellular differentiation and oncogenic processes[1][2]. No approved drugs specifically target MGAT4B, though modulation of its activity would impact a variety of glycoprotein-mediated functions.

Other names

GlcNAc-T IVbGnT-IVbN-acetylglucosaminyltransferase IVbUDP-N-acetylglucosamine: alpha-1,3-D-mannoside beta-1,4-N-acetylglucosaminyltransferase IVbGNT-IVBN-glycosyl-oligosaccharide-glycoprotein N-acetylglucosaminyltransferase IVbUNQ906/PRO1927isoenzyme Bmannosyl (alpha-1,3-)-glycoprotein beta-1,4-N-acetylglucosaminyltransferaseMGAT4B

Inhibition or modulation would theoretically alter N-glycan branching on glycoproteins, affecting cellular functions such as cell surface residence, signaling, and differentiation; however, no clinically approved drugs directly target MGAT4B as of current knowledge.