title: GlcUAβ1-3Galβ1-3Galβ1-4Xyl(2-O-phosphate) is the preferred substrate for chondroitin N-acetylgalactosaminyltransferase-1.
abstract: A deficiency in chondroitin N-acetylgalactosaminyltransferase-1 (ChGn-1) was previously shown to reduce the number of chondroitin sulfate (CS) chains, leading to skeletal dysplasias in mice, suggesting that ChGn-1 regulates the number of CS chains for normal cartilage development. Recently, we demonstrated that 2-phosphoxylose phosphatase (XYLP) regulates the number of CS chains by dephosphorylating the Xyl residue in the glycosaminoglycan-protein linkage region of proteoglycans. However, the relationship between ChGn-1 and XYLP in controlling the number of CS chains is not clear. In this study, we for the first time detected a phosphorylated tetrasaccharide linkage structure, GlcUAβ1-3Galβ1-3Galβ1-4Xyl(2-O-phosphate), in ChGn-1(-/-) growth plate cartilage but not in ChGn-2(-/-) or wild-type growth plate cartilage. In contrast, the truncated linkage tetrasaccharide GlcUAβ1-3Galβ1-3Galβ1-4Xyl was detected in wild-type, ChGn-1(-/-), and ChGn-2(-/-) growth plate cartilage. Consistent with the findings, ChGn-1 preferentially transferred N-acetylgalactosamine to the phosphorylated tetrasaccharide linkage in vitro. Moreover, ChGn-1 and XYLP interacted with each other, and ChGn-1-mediated addition of N-acetylgalactosamine was accompanied by rapid XYLP-dependent dephosphorylation during formation of the CS linkage region. Taken together, we conclude that the phosphorylated tetrasaccharide linkage is the preferred substrate for ChGn-1 and that ChGn-1 and XYLP cooperatively regulate the number of CS chains in growth plate cartilage.
authors.affiliation: From the Department of Biochemistry, Kobe Pharmaceutical University, Higashinada-ku, Kobe 658-8558, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Izumikawa
authors.affiliation: From the Department of Biochemistry, Kobe Pharmaceutical University, Higashinada-ku, Kobe 658-8558, Japan.
authors.forename: Ban
authors.initials: B
authors.lastname: Sato
authors.affiliation: From the Department of Biochemistry, Kobe Pharmaceutical University, Higashinada-ku, Kobe 658-8558, Japan.
authors.forename: Tadahisa
authors.initials: T
authors.lastname: Mikami
authors.affiliation: the Department of Regional Environment, Tottori University, Tottori 680-8551, Japan, and.
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Tamura
authors.affiliation: the Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences and Trans-disciplinary Program, Niigata University, 1-757 Asahi-machi, Chuo-ku, Niigata 951-8510, Japan.
authors.forename: Michihiro
authors.initials: M
authors.lastname: Igarashi
authors.affiliation: From the Department of Biochemistry, Kobe Pharmaceutical University, Higashinada-ku, Kobe 658-8558, Japan, kitagawa@kobepharma-u.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kitagawa
mesh_terms: D000116:Acetylgalactosamine / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D053898:Biosynthetic Pathways / Q000235:genetics; D015153:Blotting, Western; D019556:COS Cells; D002240:Carbohydrate Sequence; D002356:Cartilage / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D019902:Chondrocytes / Q000378:metabolism; D002809:Chondroitin Sulfates / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism; D006025:Glycosaminoglycans / Q000378:metabolism; D006132:Growth Plate / Q000196:embryology / Q000378:metabolism; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D017350:N-Acetylgalactosaminyltransferases / Q000235:genetics / Q000378:metabolism*; D009844:Oligosaccharides / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D013379:Substrate Specificity; D014994:Xylose / Q000378:metabolism
chemical_list: D006023:Glycoproteins; D006025:Glycosaminoglycans; D009844:Oligosaccharides; D010710:Phosphates; D002809:Chondroitin Sulfates; D014994:Xylose; D017350:N-Acetylgalactosaminyltransferases; C569943:chondroitin N-acetylgalactosaminyltransferase-1, mouse; D010744:Phosphoric Monoester Hydrolases; D000116:Acetylgalactosamine
keywords: Chondroitin Sulfate; Glycosaminoglycan; Glycosyltransferase; Phosphatase; Proteoglycan Synthesis