title: Cotranslational and posttranslocational N-glycosylation of proteins in the endoplasmic reticulum.
abstract: Asparagine linked glycosylation of proteins is an essential protein modification reaction in most eukaryotic organisms. N-linked oligosaccharides are important for protein folding and stability, biosynthetic quality control, intracellular traffic and the physiological function of many N-glycosylated proteins. In metazoan organisms, the oligosaccharyltransferase is composed of a catalytic subunit (STT3A or STT3B) and a set of accessory subunits. Duplication of the catalytic subunit gene allowed cells to evolve OST complexes that act sequentially to maximize the glycosylation efficiency of the large number of proteins that are glycosylated in metazoan organisms. We will summarize recent progress in understanding the mechanism of (a) cotranslational glycosylation by the translocation channel associated STT3A complex, (b) the role of the STT3B complex in mediating cotranslational or posttranslocational glycosylation of acceptor sites that have been skipped by the STT3A complex, and (c) the role of the oxidoreductase MagT1 in STT3B-dependent glycosylation of cysteine-proximal acceptor sites.
authors.affiliation: Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01605, United States.
authors.forename: Shiteshu
authors.initials: S
authors.lastname: Shrimal
authors.affiliation: Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01605, United States.
authors.forename: Natalia A
authors.initials: NA
authors.lastname: Cherepanova
authors.affiliation: Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01605, United States. Electronic address: reid.gilmore@umassmed.edu.
authors.forename: Reid
authors.initials: R
authors.lastname: Gilmore
mesh_terms: D000818:Animals; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006031:Glycosylation; D006602:Hexosyltransferases / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D008954:Models, Biological; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational; D011506:Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; D011506:Proteins; D006602:Hexosyltransferases; C099573:STT3A protein, human; C551978:STT3B protein, human
keywords: Asparagine linked glycosylation; Congenital disorders of glycosylation; Endoplasmic reticulum; Oligosaccharyltransferase