title: Chondroitin 4-O-sulfotransferase-1 modulates Wnt-3a signaling through control of E disaccharide expression of chondroitin sulfate.
abstract: Wnt-3a is a ligand that activates the beta-catenin-dependent pathway in Wnt signaling, which is implicated in numerous physiological events such as morphogenesis. So far, heparan sulfate (HS) proteoglycans have been highlighted as a low affinity receptor for morphogens containing Wnts. Here we show the importance of chondroitin sulfate (CS) proteoglycans in the efficient signaling of Wnt-3a and the structural features of CS required for the regulation of Wnt-3a signaling. Wnt-3a signaling was depressed in a mouse L cell mutant, called sog9, which is defective in the EXT1 gene encoding the HS-synthesizing enzyme and the chondroitin 4-O-sulfotransferase (C4ST-1) gene compared with parental L cells. The transfection of sog9 cells with C4ST-1 resulted in the recovery of Wnt-3a signaling, whereas the expression of EXT1 in sog9 cells could not restore Wnt-3a signaling. In addition, the expression level of introduced C4ST-1 correlated with the recovery of Wnt-3a signaling accompanied by the increased expression of the E disaccharide unit of CS. Interestingly, molecular interaction analyses using Biacore revealed that squid CS-E (rich in the E disaccharide unit) bound strongly to Wnt-3a (K(d)=13.2 nm) to the same extent as heparin from bovine lung (K(d)=8.43 nm). In contrast, other CS isoforms as well as HS isolated from bovine kidney showed little binding activity to Wnt-3a. Moreover, exogenously added CS-E potently inhibited the accumulation of beta-catenin induced by Wnt-3a. These results suggest that CS-E-like structures synthesized by C4ST-1 participate in Wnt-3a signaling and modulate the physiological events caused by Wnt-3a signals.
authors.affiliation: Department of Biochemistry, Kobe Pharmaceutical University, Kobe 658-8558, Japan.
authors.forename: Satomi
authors.initials: S
authors.lastname: Nadanaka
authors.forename: Miho
authors.initials: M
authors.lastname: Ishida
authors.forename: Masami
authors.initials: M
authors.lastname: Ikegami
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kitagawa
mesh_terms: D000818:Animals; D002809:Chondroitin Sulfates / Q000096:biosynthesis* / Q000235:genetics; D004187:Disaccharides / Q000096:biosynthesis*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D007739:L Cells; D051379:Mice; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D015238:Sulfotransferases / Q000235:genetics / Q000378:metabolism*; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism*; D060508:Wnt3 Protein; D060509:Wnt3A Protein; D000099058:Exostosin 1
chemical_list: D004187:Disaccharides; D051153:Wnt Proteins; D060508:Wnt3 Protein; D060509:Wnt3A Protein; C555511:Wnt3a protein, mouse; D002809:Chondroitin Sulfates; D017351:N-Acetylglucosaminyltransferases; D000099058:Exostosin 1; D015238:Sulfotransferases