MGAT4A is a glycosyltransferase that catalyzes the transfer of N-acetylglucosamine (GlcNAc) to the core structure of N-linked glycans, creating β-1,4 branched N-glycan structures essential for protein glycosylation 1. The enzyme functions in the endoplasmic reticulum and Golgi apparatus, where it modifies numerous secretory and membrane proteins to generate tri- and tetra-antennary N-glycan structures 12. Mechanistically, MGAT4A-mediated N-glycosylation regulates protein-cell surface interactions through galectin binding. In endometrial cancer with TP53 mutations, MGAT4A overexpression increases GLUT1 glucose transporter N-glycosylation, enhancing galectin-9 binding and cell membrane localization, thereby promoting glucose uptake and cancer cell proliferation 3. Similarly, in cutaneous T-cell lymphoma, reduced MGAT4A expression decreases galectin-1 binding affinity, conferring apoptosis resistance to malignant T cells 4. Clinically, MGAT4A is dysregulated across multiple malignancies. MicroRNA-mediated suppression of MGAT4A (via miR-424 or let-7c) inhibits cell cycle progression and metastatic capacity in various cancers 56. Emerging evidence from Mendelian randomization studies identifies MGAT4A as a novel genetic target associated with type 1 diabetes risk 7, suggesting roles beyond glycoprotein structure in immune regulation.