B3GNT3 Gene - Function, Expression, Mutations & Disease Associations

B3GNT3 encodes a member of the beta-1,3-N-acetylglucosaminyltransferase family. This Golgi enzyme catalyzes the transfer of N-acetylglucosamine (GlcNAc) to galactose residues with a beta-1,3 linkage, elongating poly-N-acetyllactosamine chains on N- and O-glycans. These chains are critical for cell adhesion, migration, and signaling. B3GNT3 is highly expressed in placenta, testis, and various cancer cell lines, and its dysregulation is linked to tumor progression and metastasis.

Tissue Expression

Cell Line Expression

Hotspot Mutations

Mutation functional classification

• KEGG hsa00512 - Mucin type O-glycan biosynthesis

• KEGG hsa00514 - Other types of O-glycan biosynthesis

• Reactome R-HSA-975578 - Reactions specific to the complex N-glycan synthesis

• Reactome R-HSA-5083635 - Defective B3GNT3 causes abnormal glycosylation

B3GNT3 is a type II transmembrane protein localized to the Golgi apparatus. It contains a short N-terminal cytoplasmic tail, a transmembrane domain, and a large C-terminal catalytic domain facing the Golgi lumen. The enzyme transfers N-acetylglucosamine from UDP-GlcNAc to a terminal galactose residue via a beta-1,3 linkage, extending poly-N-acetyllactosamine chains. These chains serve as ligands for galectins and other lectins, modulating cell-cell and cell-matrix interactions. B3GNT3 is essential for the biosynthesis of Lewis X and sialyl Lewis X antigens, which are involved in inflammation and cancer metastasis.