• Chondroitin sulfate chains are composed of GlcAβ1-3GalNAcβ1-4 repeating unit. Various sulfotransferases, CHST3, 7, 11, 12, 13, 14, 15, and UST, sulfate either GalNAc and GlcA residues. CS are a major functional component of aggrecan, and needed for cartilage formation and maintenance. It is also involved in interactions with growth factors pleiotrophin and midkine.
• CHST3 (C6ST-1) and CHST7 (C6ST-2) are Chondroitin 6-sulfotransferases that attach sulfate to C6 of GalNAc. They are both type II transmembrane proteins.
• CHST3 can also sulfate C6 of Gal in keratin sulfate and sialyl LacNAc oligonucleotides, but not SLe^X. It may also sulfate GAG protein linkage. This is not the only sulfoT capable of modifying keratin sulfate.
• C4-sulfation prevents C6-sulfation by CHST3.
• CHST3 KO-mice are fertile and show no obvious pathological features. Some repair mechanisms were impaired.
• CHST3 and CHST15 are secreted into culture medium.