Fucose and GlcNAc have been found only in Dictyostelium discoideum, mannose in Leishmania mexicana, and xylose in Trypanosoma cruzi.
It heterodimerizes with asparagine-linked glycosylation 14 (ALG14) homolog to form a functional UDP-GlcNAc glycosyltransferase that catalyzes the second sugar addition of the highly conserved oligosaccharide precursor in endoplasmic reticulum N-linked glycosylation.
GalNAc-Ts initiate mucin-type O-linked glycosylation in the Golgi apparatus by catalyzing the transfer of GalNAc to serine and threonine residues on target proteins.
O-linked glycosylation occurs at a later stage during protein processing, probably in the Golgi apparatus.