Alpha-1,3-mannosyl-glycoprotein 4-beta-N-acetylglucosaminyltransferase-like protein MGAT4D (MGAT4D)

MGAT4D encodes a Golgi-resident, non-catalytic member of the glycosyltransferase family, which acts as an *inhibitor* of MGAT1 (N-acetylglucosaminyltransferase I)—a key enzyme in protein N-glycan maturation[3]. Unlike canonical glycosyltransferases, MGAT4D does not exhibit intrinsic catalytic activity; instead, it regulates cell surface glycan complexity by restricting MGAT1, causing proteins to preferentially carry high-mannose N-glycans[3]. This regulatory function is particularly relevant in the testis, where MGAT4D may help orchestrate stages of spermatogenesis by influencing cell-cell interactions between Sertoli and germ cells[3]. Mutations or dysfunction in MGAT4D have been associated with congenital disorders of glycosylation, specifically type In[3]. MGAT4D’s activity is mediated through its lumenal domain within the Golgi apparatus, and there are no established direct pharmacological inhibitors or clinically validated biomarkers linked to this protein[3]. If you need direct links to sequence, structure, or pathway data, identifiers include: HGNC: 43619, NCBI Gene: 152586, Ensembl: ENSG00000205301, OMIM: 610310, UniProt: A6NG13[3].

Other names

MGAT4 family member DGlcNAcT-I inhibitory proteinGnT1IPN-acetylglucosaminyltransferase MGAT1 inhibitory proteinGlycosyltransferase 54 domain containing 1Glycosyltransferase 54 domain-containing protein

Inhibition of MGAT1-mediated glycosylation (by lumenal domain interaction rather than catalytic activity)