Important functional domains in dermatan or dermatan sulfate (DS) are generated by the action of an epimerase (which converts D-glucuronic acid into its epimer L-iduronic acid) together with 4-O-sulfation. These domains are named 4-O-sulfated iduronic acid blocks (Pachebo et al. 2009). Carbohydrate sulfotransferase 14 (CHST14) (Evers et al. 2001) mediates the transfer of sulfate to position 4 of another N-acetylgalactosamine (GalNAc) residue of D2,4(S)2-PG (sulfated on position 2 of IdoA and position 4 of GalNAc) to produce a further sulfated product D2,4,4(S)3-PG (sulfated on another GalNAc in addition to the ones above).
Carbohydrate sulfotransferase 10 (CHST10) transfers sulfate (SO4(2-)) from the high energy donor 3'-phospho-5'-adenylyl sulfate (PAPS) to position 3 of non-reducing glucuronyl (GlcA) residues of N-glycosylated proteins terminating with the saccharide sequence glucuronyl-lactosaminyl (GlcA-LacN), forming the HNK1 carbohydrate (sulfo-3GlcA-beta1,3Gal-beta1,4-GlcNAc-R). The HNK1 carbohydrate is expressed on various adhesion molecules (neural cells, natural killer cells) in the nervous system and may play a role in cell-cell and cell-substratum interactions (Ong et al. 1998, 1999).
Carbohydrate sulfotransferase 15 (CHST15) catalyses the transfer of sulfate from PAPS to the C-6 hydroxyl group of the GalNAc 4-sulfate residue of chondroitin 4-sulfate (C4S) (Ohtake et al. 2003).
Carbohydrate sulfotransferase 14 (CHST14) (Evers et al. 2001) mediates the transfer of sulfate to position 4 of N-acetylgalactosamine (GalNAc) residue of dermatan or to a further GalNAc residue of dermatan sulfate (D2,4(S)2-PG) in iduronate rich domains. As 4-O sulfation by CHST14 is essential for DS formation, defective CHST14 results in much lower levels of DS and higher levels of chondroitin sulfate (CS) being produced. DS plays an important role in human development and extracellular matrix maintenance and defective CHST14 results in Ehlers-Danlos syndrome, musculocontractural type (MIM:601776). Mutations causing this disease include V49*, R213P, R135G/L137Q, Y293, P281L and the compound heterozygotes P281L/K69* and P281L/C285S (Dundar et al. 2009, Miyake et al. 2010).
Carbohydrate sulfotransferase 1 (CHST1, keratan sulfate Gal-6 sulfotransferase) mediates the sulfation of galactose (Gal) on position 6 in keratan sulfate proteoglycans (KSPGs) (Fukuta et al. 1997).
Carbohydrate sulfotransferase 14 (CHST14 also known as D4ST-1) mediates the transfer of sulfate to position 4 of further N-acetylgalactosamine (GalNAc) residues of dermatan sulfate (DS). Defects in CHST14 cause Ehlers-Danlos syndrome, musculocontractural type (MIM:601776). The Ehlers-Danlos syndromes (EDS) are a group of connective tissue disorders that share common features such as skin hyperextensibility, articular hypermobility and tissue fragility (Beighton et al. 1998). The musculocontractural form of EDS (MIM:601776) include distinctive characteristics such as craniofacial dysmorphism, congenital contractures of fingers and thumbs, clubfeet, severe kyphoscoliosis and muscular hypotonia (Malfait et al. 2010).