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ROLES OF N-LINKED GLYCANS IN THE ENDOPLASMIC RETICULUM.

Authors :
Helenius, Ari
Aebi, Markus
Source :
Annual Review of Biochemistry. 2004, Vol. 73 Issue 1, p1019-1049. 31p. 5 Diagrams.
Publication Year :
2004

Abstract

From a process involved in cell wall synthesis in archaea and some bacteria, N-linked glycosylation has evolved into the most common covalent protein modification in eukaryotic cells. The sugars are added to nascent proteins as a core oligosaccharide unit, which is then extensively modified by removal and addition of sugar residues in the endoplasmic reticulum (ER) and the Golgi complex. It has become evident that the modifications that take place in the ER reflect a spectrum of functions related to glycoprotein folding, quality control, sorting, degradation, and secretion. The glycans not only promote folding directly by stabilizing polypeptide structures but also indirectly by serving as recognition "tags" that allow glycoproteins to interact with a variety of lectins, glycosidases, and glycosyltranferases. Some of these (such as glucosidases I and II, calnexin, and calreticulin) have a central role in folding and retention, while others (such as α-mannosidases and EDEM) target unsalvageable glycoproteins for ER-associated degradation. Each residue in the core oligosaccharide and each step in the modification program have significance for the fate of newly synthesized glycoproteins. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00664154
Volume :
73
Issue :
1
Database :
Academic Search Index
Journal :
Annual Review of Biochemistry
Publication Type :
Academic Journal
Accession number :
13942216
Full Text :
https://doi.org/10.1146/annurev.biochem.73.011303.073752