{"title":"Development of a calreticulin-targeting glycan ligand based on a hybrid binding concept.","authors":"Taiki Kuribara, Taiga Kojima, Yuka Kobayashi, Mitsuaki Hirose, Keita Shibayama, Yoichi Takeda, Kiichiro Totani","doi":"10.1093/glycob/cwaf015","DOIUrl":null,"url":null,"abstract":"<p><p>Calreticulin (CRT), a chaperone that possesses both lectin and chaperone domains, is localized in the endoplasmic reticulum (ER). CRT has diverse functions and localizations; thus, CRT is a multifunctional protein. Particularly in the ER, CRT mainly aids in the proper folding of nascent glycoproteins as lectin chaperones. Approximately one-third of cellular proteins, including disease-related proteins, are synthesized in the ER. The lectin chaperones CRT and calnexin facilitate the correct folding of these glycoproteins; hence, these chaperones are essential for cells. Various CRT ligands have been reported, mainly composed of Glc1Man9GlcNAc2-type glycan. However, it remains problematic for the complicated synthesis and preparation, and it interacts with glycoprotein folding-related proteins in the ER other than CRT. This suggests that the development of CRT ligands still can be improved. In this study, we developed a hybrid binding concept, which encompasses concurrent binding of ligands to CRT lectin and chaperone domains. We synthesized a CRT-targeting glycan ligand with a glycan and hydrophobic aglycone for CRT lectin and chaperone domain binding, respectively. The thermal shift assay with the CRT-targeting glycan demonstrated that binding was enhanced by simultaneous glycan and hydrophobic aglycone binding. The affinity of the CRT-targeting ligand showed isothermal titration calorimetry approximately 50-fold stronger than that of the glycan alone, thereby supporting the hybrid binding concept. In addition, the CRT-targeting ligand inhibited chaperone function. Overall, these results indicate that the hybrid binding concept may be useful as a novel strategy for the development of CRT ligands and inhibitors.</p>","PeriodicalId":12766,"journal":{"name":"Glycobiology","volume":" ","pages":""},"PeriodicalIF":3.4000,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Glycobiology","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1093/glycob/cwaf015","RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Calreticulin (CRT), a chaperone that possesses both lectin and chaperone domains, is localized in the endoplasmic reticulum (ER). CRT has diverse functions and localizations; thus, CRT is a multifunctional protein. Particularly in the ER, CRT mainly aids in the proper folding of nascent glycoproteins as lectin chaperones. Approximately one-third of cellular proteins, including disease-related proteins, are synthesized in the ER. The lectin chaperones CRT and calnexin facilitate the correct folding of these glycoproteins; hence, these chaperones are essential for cells. Various CRT ligands have been reported, mainly composed of Glc1Man9GlcNAc2-type glycan. However, it remains problematic for the complicated synthesis and preparation, and it interacts with glycoprotein folding-related proteins in the ER other than CRT. This suggests that the development of CRT ligands still can be improved. In this study, we developed a hybrid binding concept, which encompasses concurrent binding of ligands to CRT lectin and chaperone domains. We synthesized a CRT-targeting glycan ligand with a glycan and hydrophobic aglycone for CRT lectin and chaperone domain binding, respectively. The thermal shift assay with the CRT-targeting glycan demonstrated that binding was enhanced by simultaneous glycan and hydrophobic aglycone binding. The affinity of the CRT-targeting ligand showed isothermal titration calorimetry approximately 50-fold stronger than that of the glycan alone, thereby supporting the hybrid binding concept. In addition, the CRT-targeting ligand inhibited chaperone function. Overall, these results indicate that the hybrid binding concept may be useful as a novel strategy for the development of CRT ligands and inhibitors.
期刊介绍:
Established as the leading journal in the field, Glycobiology provides a unique forum dedicated to research into the biological functions of glycans, including glycoproteins, glycolipids, proteoglycans and free oligosaccharides, and on proteins that specifically interact with glycans (including lectins, glycosyltransferases, and glycosidases).
Glycobiology is essential reading for researchers in biomedicine, basic science, and the biotechnology industries. By providing a single forum, the journal aims to improve communication between glycobiologists working in different disciplines and to increase the overall visibility of the field.