Beta-1,3-Galactosyltransferase Like Protein (b3GALTL)

B3GALTL is a beta-1,3-glucosyltransferase involved in the synthesis of the unusual O-linked disaccharide glucosyl-beta-1,3-fucose-O- found on the thrombospondin type-1 repeats (TSRs) of many biologically important proteins. Biosynthesis of glucosyl-beta-1,3-fucose-O- is initiated by protein O-fucosyltransferase-2 (POFUT2), which attaches the fucosyl residue to a serine or threonine within the TSR. The deduced 498-amino acid protein is a type II membrane protein with a 4-residue N-terminal cytoplasmic domain, a transmembrane domain, and a large C-terminal portion containing a stem region and a catalytic domain. The catalytic domains contains a triple-aspartate (DDD) motif at its core, a conserved pattern of cysteines, a C-terminal KDEL-like motif, and other residues and motifs conserved in beta-3-glycosyltransferases.