title: Calreticulin discriminates the proximal region at the N-glycosylation site of Glc1Man9GlcNAc2 ligand.
abstract: Calreticulin (CRT) is well known as a lectin-like chaperone that recognizes Glc1Man9GlcNAc2 (G1M9)-glycoproteins in the endoplasmic reticulum (ER). However, whether CRT can directly interact with the aglycone moiety (protein portion) of the glycoprotein remains controversial. To improve our understanding of CRT interactions, structure-defined G1M9-derivatives with different aglycones (-OH, -Gly-NH2, and -Gly-Glu-(t)Bu) were used as CRT ligands, and their interactions with recombinant CRT were analyzed using thermal shift analysis. The results showed that CRT binds strongly to a G1M9-ligand in the order -Gly-Glu-(t)Bu > -Gly-NH2 > -OH, which is the same as that of the reglucosylation of Man9GlcNAc2 (M9)-derivatives by the folding sensor enzyme UGGT (UDP-glucose: glycoprotein glucosyltransferase). Our results indicate that, similar to UGGT, CRT discriminates the proximal region at the N-glycosylation site, suggesting a similar mechanism mediating the recognition of aglycone moieties in the ER glycoprotein quality control system.
authors.affiliation: Department of Materials and Life Science, Seikei University, 3-3-1 Kichijoji-kita, Musashino, Tokyo 180-8633, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Hirano
authors.affiliation: Department of Materials and Life Science, Seikei University, 3-3-1 Kichijoji-kita, Musashino, Tokyo 180-8633, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Adachi
authors.affiliation: Synthetic Cellular Chemistry Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; ERATO, Japan Science and Technology Agency, Ito Glycotrilogy Project, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Yukishige
authors.initials: Y
authors.lastname: Ito
authors.affiliation: Department of Materials and Life Science, Seikei University, 3-3-1 Kichijoji-kita, Musashino, Tokyo 180-8633, Japan. Electronic address: ktotani@st.seikei.ac.jp.
authors.forename: Kiichiro
authors.initials: K
authors.lastname: Totani
mesh_terms: D000117:Acetylglucosamine / Q000737:chemistry; D000818:Animals; D001665:Binding Sites; D037282:Calreticulin / Q000378:metabolism*; D002645:Chickens; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005964:Glucosyltransferases / Q000737:chemistry; D006023:Glycoproteins / Q000737:chemistry; D006031:Glycosylation; D006358:Hot Temperature; D057927:Hydrophobic and Hydrophilic Interactions; D007136:Immunoglobulins / Q000737:chemistry; D008024:Ligands; D018832:Molecular Chaperones / Q000737:chemistry; D011485:Protein Binding; D017510:Protein Folding; D011994:Recombinant Proteins / Q000737:chemistry
chemical_list: D037282:Calreticulin; D006023:Glycoproteins; C016512:IgY; D007136:Immunoglobulins; D008024:Ligands; D018832:Molecular Chaperones; D011994:Recombinant Proteins; D005964:Glucosyltransferases; D000117:Acetylglucosamine
keywords: Chaperone; Endoplasmic reticulum; Glycoprotein; Lectin; Thermal shift analysis