title: Generation and degradation of free asparagine-linked glycans.
abstract: Asparagine (N)-linked protein glycosylation, which takes place in the eukaryotic endoplasmic reticulum (ER), is important for protein folding, quality control and the intracellular trafficking of secretory and membrane proteins. It is known that, during N-glycosylation, considerable amounts of lipid-linked oligosaccharides (LLOs), the glycan donor substrates for N-glycosylation, are hydrolyzed to form free N-glycans (FNGs) by unidentified mechanisms. FNGs are also generated in the cytosol by the enzymatic deglycosylation of misfolded glycoproteins during ER-associated degradation. FNGs derived from LLOs and misfolded glycoproteins are eventually merged into one pool in the cytosol and the various glycan structures are processed to a near homogenous glycoform. This article summarizes the current state of our knowledge concerning the formation and catabolism of FNGs.
authors.affiliation: Glycometabolome Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Harada
authors.forename: Hiroto
authors.initials: H
authors.lastname: Hirayama
authors.forename: Tadashi
authors.initials: T
authors.lastname: Suzuki
mesh_terms: D001216:Asparagine / Q000378:metabolism*; D053898:Biosynthetic Pathways / Q000502:physiology*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006031:Glycosylation; D006868:Hydrolysis; D008070:Lipopolysaccharides / Q000378:metabolism; D008954:Models, Biological; D011134:Polysaccharides / Q000096:biosynthesis* / Q000378:metabolism*; D017510:Protein Folding
chemical_list: D008070:Lipopolysaccharides; D011134:Polysaccharides; C023023:lipid-linked oligosaccharides; D001216:Asparagine