Oligosaccharide transport: pumping waste from the ER into lysosomes.
N-glycans play important roles during the folding and secretion of glycoproteins. Surprisingly, during the N-glycosylation of glycoproteins, considerable amounts of unconjugated polymannose-type oligosaccharides ('free OS') are generated. Although free oligosaccharides have no known function in mammalian cells, a sophisticated cellular machinery enables them to be cleared from the endoplasmic reticulum (ER) into the cytosol and then re-enter the endomembrane system at the level of the lysosome. One possible function of this pathway is to stop free OS from interfering with the carbohydrate-dependent aspects of glycoprotein folding and transport along the secretory pathway.
Moore
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INSERM U504, Bâtiment INSERM, 16 Avenue Paul Vaillant-Couturier, 94807 Villejuif, France. u504@vjf.inserm.fr
D001692:Biological Transport; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006801:Humans; D008247:Lysosomes / Q000378:metabolism*; D008358:Mannose / Q000737:chemistry; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism*; D008363:alpha-Mannosidosis / Q000378:metabolism
D009844:Oligosaccharides; D008358:Mannose