title: Endoplasmic reticulum-associated degradation of glycoproteins bearing Man5GlcNAc2 and Man9GlcNAc2 species in the MI8-5 CHO cell line.
abstract: Endoplasmic reticulum-associated degradation of newly synthesized glycoproteins has been demonstrated previously using various mammalian cell lines. Depending on the cell type, glycoproteins bearing Man9 glycans and glycoproteins bearing Man5 glycans can be efficiently degraded. A wide variety of variables can lead to defective synthesis of lipid-linked oligosaccharides and, therefore, in mammalian cells, species derived from Man9GlcNAc2 or Man5GlcNAc2 are often recovered on newly synthesized glycoproteins. The degradation of glycoproteins bearing these two species has not been studied. We used a Chinese hamster ovary cell line lacking Glc-P-Dol-dependent glucosyltransferase I to generate various proportions of Man5GlcNAc2 and Man9GlcNAc2 on newly synthesized glycoproteins. By studying the structure of the soluble oligomannosides produced by degradation of these glycoproteins, we demonstrated the presence of a higher proportion of soluble oligomannosides originating from truncated glycans, showing that glycoproteins bearing Man5GlcNAc2 glycans are degraded preferentially.
authors.affiliation: Unité de Glycobiologie Structurale et Fonctionnelle, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France.
authors.forename: François
authors.initials: F
authors.lastname: Foulquier
authors.forename: Sandrine
authors.initials: S
authors.lastname: Duvet
authors.forename: André
authors.initials: A
authors.lastname: Klein
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Mir
authors.forename: Frédéric
authors.initials: F
authors.lastname: Chirat
authors.forename: René
authors.initials: R
authors.lastname: Cacan
mesh_terms: D000818:Animals; D001426:Bacterial Proteins; D016466:CHO Cells; D002851:Chromatography, High Pressure Liquid; D006224:Cricetinae; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005964:Glucosyltransferases; D006023:Glycoproteins / Q000378:metabolism*; D008351:Mannans / Q000378:metabolism*; D008361:Mannosidases / Q000378:metabolism; D009844:Oligosaccharides / Q000378:metabolism*; D011134:Polysaccharides / Q000378:metabolism; D011506:Proteins / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D006023:Glycoproteins; D008351:Mannans; D009844:Oligosaccharides; D011134:Polysaccharides; D011506:Proteins; C475461:mannosyl(9)-N-acetylglucosamine2; C067118:GTF-I protein, Streptococcus; C058642:mannosyl(5)-N-acetyl(2)-glucose; D005964:Glucosyltransferases; C489364:glucosyltransferase I; D008361:Mannosidases