Lysosomal oligosaccharide catabolism

Stable Identifier
R-HSA-8853383
Type
Pathway
Species
Homo sapiens
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N-Glycosylation is one of the most common co- and posttranslational modifications of eukaryotic proteins occurring in the ER lumen. N-glycosylation plays pivotal roles in protein folding and intra- or inter-cellular trafficking of N-glycosylated proteins. Quality control mechanisms in the ER sift out incorrectly-folded proteins from correctly-folded proteins, the former then destined for degradation. Incorrectly-folded N-glycans are exported to the cytosol where the process of degradation begins. Once the unfolded protein is cleaved from the oligosaccharide (forming free oligosaccharides, fOS), step-wise degradation of mannose moieties, both in the cytosol (Suzuki & Harada 2014) and then in the lysosome (Aronson & Kuranda 1989, Winchester 2005), results in complete degradation. Breakdown must be complete to avoid lysosomal storage diseases that occur when fragments as small as dimers are left undigested.

Literature References
PubMed ID Title Journal Year
2531691 Lysosomal degradation of Asn-linked glycoproteins

Aronson NN, Jr, Kuranda, MJ

FASEB J 1989
26206502 Cytosolic-free oligosaccharides are predominantly generated by the degradation of dolichol-linked oligosaccharides in mammalian cells

Harada, Y, Masahara-Negishi, Y, Suzuki, T

Glycobiology 2015
15647514 Lysosomal metabolism of glycoproteins

Winchester, B

Glycobiology 2005
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