Carbohydrate Sulfotransferase 13 (CHST13)

C4ST3 transfers sulfate to the C-4 hydroxyl of beta-1,4-linked GalNAc flanked by GlcUA residues in chondroitin. The C4ST3 cDNA encodes a predicted type II transmembrane protein of 341 amino acids with a 12-amino acid cytoplasmic domain and a 311-amino acid luminal domain. It has a single potential N-linked glycosylation site and a calculated molecular mass of 39 kD. The C4ST3 protein shares 45% sequence identity with C4ST1 (CHST11) and 23 to 29% with several other members of the HNK1 family of sulfotransferases. Northern blot analysis detected a single 1.2-kb transcript in adult liver. RNA dot-blot analysis detected expression of C4ST3 at high levels in adult liver and at significantly lower levels in adult kidney, lymph nodes, and fetal liver.