title: Influence of aglycone structures on N-glycan processing reactions in the endoplasmic reticulum.
abstract: Glycoprotein N-linked oligosaccharides in the endoplasmic reticulum function as tags to regulate glycoprotein folding, sorting, secretion and degradation. Since the N-glycan structure of a glycoprotein should reflect the folding state, N-glycan processing may be affected by the aglycone state. In this study, we examined the influence of aglycone structures on N-glycan processing using synthetic substrates. We prepared (Glc1)Man9GlcNAc2linked to hydrophobic BODIPY-dye with a systematic series of different linker lengths. With these compounds, glucose transfer, glucose trimming and mannose trimming reactions of an endoplasmic reticulum fraction were examined. The results showed that substrates with shorter linkers between the N-glycan and hydrophobic patch had higher activities for both the glucose transfer and the mannose trimming reactions. In contrast, the glucose trimming reaction showed lower activity when substrates had shorter linkers. Thus, the reactivity for N-linked oligosaccharide processing of glycoproteins in the endoplasmic reticulum might be tunable by the aglycone structure, e.g., protein portion of glycoproteins.
authors.affiliation: Department of Materials and Life Science, Seikei University, 3-3-1 Kichijoji-kitamachi, Musashino, Tokyo, 180-8633, Japan. Electronic address: ktotani@st.seikei.ac.jp.
authors.forename: Kiichiro
authors.initials: K
authors.lastname: Totani
authors.affiliation: Department of Materials and Life Science, Seikei University, 3-3-1 Kichijoji-kitamachi, Musashino, Tokyo, 180-8633, Japan.
authors.forename: Kenta
authors.initials: K
authors.lastname: Yamaya
authors.affiliation: Department of Materials and Life Science, Seikei University, 3-3-1 Kichijoji-kitamachi, Musashino, Tokyo, 180-8633, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Hirano
authors.affiliation: Synthetic Cellular Chemistry Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
authors.forename: Yukishige
authors.initials: Y
authors.lastname: Ito
mesh_terms: D000117:Acetylglucosamine / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D001896:Boron Compounds / Q000737:chemistry / Q000378:metabolism; D037282:Calreticulin / Q000737:chemistry / Q000378:metabolism*; D002240:Carbohydrate Sequence; D002458:Cell Fractionation; D004721:Endoplasmic Reticulum / Q000737:chemistry / Q000378:metabolism*; D005456:Fluorescent Dyes / Q000737:chemistry / Q000378:metabolism; D005947:Glucose / Q000737:chemistry / Q000378:metabolism; D005959:Glucosidases / Q000737:chemistry / Q000378:metabolism*; D005964:Glucosyltransferases / Q000737:chemistry / Q000378:metabolism*; D006023:Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D006031:Glycosylation; D022781:Hepatocytes / Q000737:chemistry / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D008099:Liver / Q000737:chemistry / Q000378:metabolism; D008297:Male; D008358:Mannose / Q000737:chemistry / Q000378:metabolism; D008361:Mannosidases / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D011487:Protein Conformation
chemical_list: C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D001896:Boron Compounds; D037282:Calreticulin; D005456:Fluorescent Dyes; D006023:Glycoproteins; D005964:Glucosyltransferases; D005959:Glucosidases; D008361:Mannosidases; D005947:Glucose; D008358:Mannose; D000117:Acetylglucosamine
keywords: Aglycone specificity; Calreticulin; Glucosidase; Glucosyl transferase; High-mannose glycan; Mannosidase