Alpha-1,3-mannosyl-glycoprotein 4-beta-N-acetylglucosaminyltransferase A (MGAT4A)

Alpha-1,3-mannosyl-glycoprotein 4-beta-N-acetylglucosaminyltransferase A (MGAT4A) is a type II membrane-bound glycosyltransferase enzyme, primarily localized to the Golgi apparatus, responsible for catalyzing the addition of N-acetylglucosamine (GlcNAc) in a beta-1,4 linkage to the alpha-1,3-mannose arm of N-glycans. This modification is critical for the formation of tri- and tetra-antennary N-glycan branches, which influence glycoprotein function, stability, and cellular localization. MGAT4A-mediated glycosylation is essential for normal glycoprotein biosynthesis, regulation of glucose transporter 2 (GLUT2) localization and function in pancreatic beta cells, and plays a role in cell differentiation and oncogenic processes. Aberrant expression or loss of function of MGAT4A is implicated in diseases such as type 2 diabetes (by dysregulating GLUT2 trafficking and insulin secretion) and cancer (by affecting cell surface glycoprotein dynamics and tumor invasiveness). Structurally, the enzyme contains a unique C-terminal lectin domain that regulates its catalytic activity and substrate recognition

Other names

Alpha-1,3-mannosyl-glycoprotein 4-beta-N-acetylglucosaminyltransferase AMGAT4AGlcNAc-T IVaGnT-IVaN-acetylglucosaminyltransferase IVaGnT-IvaGnT-4aGNT-IVGNT-IVAUDP-N-acetylglucosamine:alpha-1,3-D-mannoside beta-1,4-N-acetylglucosaminyltransferase IVaN-glycosyl-oligosaccharide-glycoprotein N-acetylglucosaminyltransferase IVa

Inhibition/modulation would alter N-glycan branching patterns, affecting function and stability of surface glycoproteins, such as glucose transporter 2 (GLUT2)