Beta-1,4-mannosyl-glycoprotein 4-beta-N-acetylglucosaminyltransferase (MGAT3)

Beta-1,4-mannosyl-glycoprotein 4-beta-N-acetylglucosaminyltransferase (MGAT3), also known as N-acetylglucosaminyltransferase III (GnT-III), is a key glycosyltransferase enzyme involved in N-glycan biosynthesis. It catalyzes the transfer of N-acetylglucosamine (GlcNAc) in a Beta-1,4-linkage to the beta-linked mannose of the trimannosyl core of N-linked oligosaccharides, producing the “bisecting GlcNAc” structure. This modification profoundly alters the structure and function of N-glycans, suppressing further branching and affecting protein properties such as cell surface recognition, signaling, and adhesion. MGAT3 activity is closely linked to regulation of cell migration, invasion, and metastasis, particularly through its effects on E-cadherin and integrin glycosylation during epithelial-mesenchymal transition (EMT) processes in cancer. Its expression can be epigenetically regulated and aberrant activity or levels are implicated in cancer progression and potentially other diseases characterized by altered glycosylation. Note: MGAT3 (glycosyltransferase, on chromosome 22) should not be confused with MOGAT3/Monoacylglycerol O-acyltransferase 3 (an unrelated metabolic enzyme on chromosome 7). All information here refers to the glycosyltransferase, not the metabolic enzyme.

Other names

MGAT3GGNT3GNT-IIIGlcNAc-T IIIN-acetylglucosaminyltransferase IIIGNT3Beta-1,4-mannosylglycoprotein 4-beta-N-acetylglucosaminyltransferaseN-glycosyl-oligosaccharide-glycoprotein N-acetylglucosaminyltransferase III

Not applicable (no approved drugs directly targeting MGAT3). In theory, inhibition of MGAT3 would reduce bisecting GlcNAc structures on N-glycans, potentially affecting cell adhesion, migration, and tumor suppression pathways. Activation would have the opposite effects, enhancing bisecting GlcNAc presence and potentially strengthening cell adhesion and metastasis suppression