N-linked glycosylation machinery (N-glycosylation machinery)

The N-linked glycosylation machinery is a highly conserved, multi-component system located within the endoplasmic reticulum (ER) and Golgi apparatus that facilitates the covalent attachment of oligosaccharides to asparagine residues on nascent proteins [UniProt]. This machinery includes the oligosaccharyltransferase (OST) complex, which transfers a pre-assembled Glc3Man9GlcNAc2 glycan from a dolichol pyrophosphate carrier to the protein, as well as various glycosyltransferases (ALG genes) and processing enzymes like glucosidases and mannosidases [PubMed: 29476157]. This process is fundamental for ensuring correct protein folding, stability, and quality control through the ERAD pathway [NCBI]. Dysregulation of this machinery is the primary cause of Congenital Disorders of Glycosylation (CDG) and is frequently exploited by cancer cells for metastasis and by enveloped viruses, such as HIV and SARS-CoV-2, to shield their surface proteins from the immune system [PubMed: 32555388]. Therapeutic strategies targeting this machinery involve small-molecule inhibitors like NGI-1 or iminosugars such as Celgosivir, which aim to disrupt viral replication or tumor growth, though the essential nature of glycosylation in normal physiology presents significant challenges regarding therapeutic window and toxicity [PubMed: 27548280].

Other names

N-glycosylation pathwayAsparagine-linked glycosylation pathwayN-glycan biosynthesis machineryDolichol-linked oligosaccharide synthesis and transfer system

Inhibition of the oligosaccharyltransferase (OST) complex, inhibition of alpha-glucosidases I and II, inhibition of alpha-mannosidases, or disruption of the synthesis of dolichol-linked oligosaccharide precursors.