tailieunhanh - Báo cáo khóa học: 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 bearingMan9 glycans and glycoproteins bearing Man5 glycans can be efficiently degraded. Awide variety of variables can lead to defective synthesis of lipid-linked oligosaccharides and, therefore, in mammalian cells, species derived fromMan9GlcNAc2 orMan5GlcNAc2 are often recovered on newly synthesized glycoproteins. . | Eur. J. Biochem. 271 398-404 2004 FEBS 2003 doi Endoplasmic reticulum-associated degradation of glycoproteins bearing Man5GlcNAc2 and Man9GlcNAc2 species in the MI8-5 CHO cell line Francois Foulquier Sandrine Duvet Andre Klein Anne-Marie Mir Frederic Chirat and Rene Cacan Unite de Glycobiologie Structurale et Fonctionnelle CNRS-UMR 8576 IFR 118 GDR CNRS 2590 Universite des Sciences et Technologies de Lille Villeneuve d Ascq France 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 -iik 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. Keywords degradation signal lipid intermediates manno-sidase activity N-glycosylation soluble oligomannosides. The N-glycosylation process is characterized by the transfer en bloc of a preassembled oligosaccharide on to a nascent protein. According to the specificity of the oligosaccharyltransferase it has been demonstrated in vitro that a wide variety of assembly intermediates Glc 0-3 Man 0-9 GlcNAc2-Pp-Dol can serve as the donor substrate for