Endoplasmic reticulum-associated degradation of glycoproteins bearing Man5GlcNAc2 and Man9GlcNAc2 species in the MI8-5 CHO cell line.
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.
Foulquier
François
F
Unité de Glycobiologie Structurale et Fonctionnelle, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France.
Duvet
Sandrine
S
Klein
André
A
Mir
Anne-Marie
AM
Chirat
Frédéric
F
Cacan
René
R
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
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