Intracellular functions of N-linked glycans.

  title={Intracellular functions of N-linked glycans.},
  author={Ari Helenius and Markus Aebi},
  volume={291 5512},
N-linked oligosaccharides arise when blocks of 14 sugars are added cotranslationally to newly synthesized polypeptides in the endoplasmic reticulum (ER). These glycans are then subjected to extensive modification as the glycoproteins mature and move through the ER via the Golgi complex to their final destinations inside and outside the cell. In the ER and in the early secretory pathway, where the repertoire of oligosaccharide structures is still rather small, the glycans play a pivotal role in… 

Glycosylation of Proteins in the Golgi Apparatus

Some of the most common forms of Golgi protein glycosylation are discussed: mucin-type O-linked gly cosylation, N- linked glycosolation, and the formation of glycosaminoglycans.

Glycan Engineering in Transgenic Plants

This chapter describes the main aspects of the N - glycan biosynthesis in plants as well as strategies that have been developed to engineer this N - Glycosylation pathway in order to allow the production in transgenic plants of pharmaceutical proteins that carry human - like glycans.

Carbohydrate Synthesis Towards Glycobiology

The past decade has witnessed tremendous progress in the development of efficient chemical and chemoenzymatic methods for synthesizing structurally well-defined complex carbohydrates, which were used for addressing critical biological problems that were otherwise difficult to tackle by genetic approaches.

Controlling N-linked glycan site occupancy.

Endo-β-N-acetylglucosaminidase, an enzyme involved in processing of free oligosaccharides in the cytosol

The identification of the gene encoding human cytosolic ENGase, a key enzyme involved in the processing of free oligosaccharides in the cytosol, was reported, suggesting that this enzyme is involved in basic biological processes in eukaryotic cells.

Glycosylation Quality Control by the Golgi Structure.




How N-linked oligosaccharides affect glycoprotein folding in the endoplasmic reticulum.

A review of recent findings suggest that the N-linked oligosaccharides may play multiple roles during the conformational maturation of glycoproteins, needed to stabilize folded domains and provide solubility-enhancing polar surface groups that prevent aggregation of folding intermediates.

Role of N-oligosaccharide endoplasmic reticulum processing reactions in glycoprotein folding and degradation.

The interaction between CNX/CRT and a monoglucosylated glycan is one of the alternative mechanisms by which cells retain not yet properly folded glycoproteins in the ER and enhances folding efficiency by preventing protein aggregation and thus allowing intervention of classical chaperones and other folding-assisting proteins.

The dolichol pathway of N-linked glycosylation.

Role of N-linked oligosaccharide recognition, glucose trimming, and calnexin in glycoprotein folding and quality control.

It is proposed that the ER contains a unique folding and quality control machinery in which calnexin acts as a chaperone that binds proteins with partially glucose-trimmed carbohydrate side chains, and glucosidases I and II serve as signal modifiers and UDP-glucose:glycoprotein glucosyltransferase, as a folding sensor.

From peptidoglycan to glycoproteins: common features of lipid-linked oligosaccharide biosynthesis.

The presence of dolichyl phosphate and a family of saturated isoprenoid lipids in Archaebacteria suggests a possible evolutionary link between the bacterial and eukaryotic systems.

Asparagine-linked Oligosaccharides Protect Lamp-1 and Lamp-2 from Intracellular Proteolysis*

Endoglycosidase H treated cells provide direct evidence that Asn-linked oligosaccharides protect a subset of lysosomal membrane proteins from proteolytic digestion in intact cells.

Protein glucosylation and its role in protein folding.

  • A. J. Parodi
  • Biology, Chemistry
    Annual review of biochemistry
  • 2000
The lectin-monoglucosylated oligosaccharide interaction is one of the alternative ways by which cells retain improperly folded glycoproteins in the endoplasmic reticulum and increases folding efficiency, prevents premature glycoprotein oligomerization and degradation, and suppresses formation of non-native disulfide bonds.

Biochemistry, molecular biology, and genetics of the oligosaccharyltransferase

  • S. SilbersteinR. Gilmore
  • Biology, Chemistry
    FASEB journal : official publication of the Federation of American Societies for Experimental Biology
  • 1996
Protein sequence comparisons reveal significant homologies between vertebrate, invertebrate, plant, and fungal OST subunits consistent with the evolutionary conservation of N‐linked glycosylation.