Carbohydrate sulfotransferase 6
Function
Sulfotransferase that utilizes 3'-phospho-5'-adenylyl sulfate (PAPS) as sulfonate donor to catalyze the transfer of sulfate to position 6 of non-reducing N-acetylglucosamine (GlcNAc) residues of keratan (PubMed:11278593, PubMed:11352640, PubMed:12218059, PubMed:17690104). Cooperates with B4GALT4 galactosyltransferase and B3GNT7 N-acetylglucosaminyltransferase to construct and elongate the sulfated disaccharide unit [->3Galbeta1->4(6-sulfoGlcNAcbeta)1->] within keratan sulfate polymer. Involved in biosynthesis of keratan sulfate in cornea, with an impact on proteoglycan fibril organization and corneal transparency (PubMed:11278593, PubMed:12218059, PubMed:17690104). Involved in sulfation of endothelial mucins such as GLYCAM1 (PubMed:11352640).
Involvement in disease
Macular dystrophy, corneal
MCD
An ocular disease characterized by bilateral, progressive corneal opacification, and reduced corneal sensitivity. Onset occurs in the first decade, usually between ages 5 and 9. Painful attacks with photophobia, foreign body sensations, and recurrent erosions occur in most patients. The disease is due to deposition of an unsulfated keratan sulfate both within the intracellular space (within the keratocytes and endothelial cells) and in the extracellular corneal stroma. Macular corneal dystrophy is divided into the clinically indistinguishable types I, IA, and II based on analysis of the normally sulfated, or antigenic, keratan sulfate levels in serum and immunohistochemical evaluation of the cornea. Patients with types I and IA macular corneal dystrophy have undetectable serum levels of antigenic keratan sulfate, whereas those with type II macular corneal dystrophy have normal or low levels, depending on the population examined.
None
The disease is caused by variants affecting the gene represented in this entry. CHST6 homozygous missense mutations have been observed in patients with macular corneal dystrophy type I, while type II patients show a large deletion and replacement in the upstream region of CHST6. The only missense mutation for type II is Cys-50, which is heterozygous with a replacement in the upstream region on the other allele of CHST6.
Sequence Similarities
Belongs to the sulfotransferase 1 family. Gal/GlcNAc/GalNAc subfamily.
Tissue Specificity
Expressed in cornea. Mainly expressed in brain. Also expressed in spinal cord and trachea.
Cellular localization
- Golgi apparatus membrane
- Single-pass type II membrane protein
Alternative names
Carbohydrate sulfotransferase 6, Corneal N-acetylglucosamine-6-O-sulfotransferase, Galactose/N-acetylglucosamine/N-acetylglucosamine 6-O-sulfotransferase 4-beta, N-acetylglucosamine 6-O-sulfotransferase 5, C-GlcNAc6ST, hCGn6ST, GST4-beta, GlcNAc6ST-5, Gn6st-5, CHST6