Beta-1,3-N-Acetylglucosaminyltransferase 3 (b3GNT3)

b3GNT3  is a type II transmembrane protein and contains a signal anchor that is not cleaved. It prefers the substrates of lacto-N-tetraose and lacto-N-neotetraose, and is involved in the biosynthesis of poly-N-acetyllactosamine chains and the biosynthesis of the backbone structure of dimeric sialyl Lewis a. It plays dominant roles in L-selectin ligand biosynthesis, lymphocyte homing and lymphocyte trafficking.The predicted TMEM3 protein contains an 11-residue N-terminal cytoplasmic domain, a 21-residue transmembrane segment, and a 340-residue stem region and catalytic domain with 3 potential N-linked glycosylation sites. Western blot analysis indicated that FLAG-fused TMEM3 was expressed as an approximately 42- to 45-kD glycoprotein.