Cytoplasmic peptide:N-glycanase and catabolic pathway for free N-glycans in the cytosol.
Peptide:N-glycanase (PNGase) releases N-glycans from glycoproteins/glycopeptides. Cytoplasmic PNGase is widely recognized as a component of machinery for ER-associated degradation (ERAD), i.e. proteasomal degradation of misfolded, newly synthesized (glyco)proteins that have been exported from the ER. The enzyme belongs to the "transglutaminase superfamily" that contains a putative catalytic triad of cysteine, histidine, and aspartic acid. The mammalian orthologues of PNGase contain the N-terminal PUB domain that serves as the protein-protein interaction domain. The C-terminus of PNGase was recently found to be a novel carbohydrate-binding domain. Taken together, these observations indicate that C-terminus of mammalian PNGase is important for recognition of the substrates while N-terminus of this enzyme is involved in assembly of a degradation complex.
Suzuki
Tadashi
T
Department of Biochemistry, 21st Center of Excellence Program, Osaka University Graduate School of Medicine, Japan. tsuzuki_gm@riken.jp
D000818:Animals; D003593:Cytoplasm / Q000201:enzymology*; D003600:Cytosol / Q000378:metabolism; D006801:Humans; D053858:Metabolic Networks and Pathways; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase / Q000378:metabolism*; D011134:Polysaccharides / Q000378:metabolism*; D054730:Protein Interaction Domains and Motifs; D011506:Proteins / Q000378:metabolism
D011134:Polysaccharides; D011506:Proteins; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase