Glycosyltransferase that participates in the transfer of N-acetylglucosamine (GlcNAc) to the core mannose residues of N- linked glycans. Catalyzes the formation of the GlcNAcbeta1-4 branch on the GlcNAcbeta1-2Manalpha1-3 arm of the core structure of N-linked glycans. Essential for the production of tri- and tetra-antennary N-linked sugar chains. Does not catalyze the transfer of GlcNAc to the Manalpha1-6 arm to form GlcNAcBeta1-4Manalpha1-6 linkage ('GnT-VI' activity).
Alpha-1,3-mannosyl-glycoprotein 4-beta-N-acetylglucosaminyltransferase C; GlcNAc-T IVc; gnT-IVc; HGNT-IV-H; mannosyl (alpha-1,3-)-glycoprotein beta-1,4-N-acetylglucosaminyltransferase, isozyme C (putative); MGAT4 family, member C; N-acetylglucosaminyltransferase IV homolog; N-acetylglucosaminyltransferase IVc; N-glycosyl-oligosaccharide-glycoprotein N-acetylglucosaminyltransferase IVc; UDP-N-acetylglucosamine: alpha-1,3-D-mannoside beta-1,4-N-acetylglucosaminyltransferase IVc; UDP-N-acetylglucosamine:a-1,3-D-mannoside beta-1,4-N-acetylglucosaminyltransferase IV; UDP-N-acetylglucosamine:a-1,3-D-mannoside beta-1,4-N-acetylglucosaminyltransferase IV-homolog