Stuart E. H. Moore

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Free polymannose oligosaccharides have recently been localized to both the vesicular and cytosolic compartments of HepG2 cells. Here we investigated the possibility that free oligosaccharides originating in the lumen of the endoplasmic reticulum (ER) are transported directly into the cystosol. Incubation of permeabilized cells in the absence of ATP at 37(More)
Two highly conserved eukaryotic gene products of unknown function showing homology to glycosyltransferases involved in the second steps of bacterial peptidoglycan (Murg) and capsular polysaccharide (Cps14f/Cps14g) biosynthesis have been identified in silico. The amino acid sequence of the eukaryotic protein that is homologous to the lipid acceptor- and(More)
Free oligosaccharides (fOS) are generated during glycoprotein biosynthesis in mammalian cells. Here we report on the origin and fate of these structures in the yeast Saccharomyces cerevisiae. After metabolic radiolabelling with [2-(3)H]mannose ([2-(3)H]Man) for 30 min, Man(8)GlcNAc(2) was identified as the predominant fOS in this organism, and radioactivity(More)
We report the cloning of three splice variants of the FUT10 gene, encoding for active alpha-l-fucosyltransferase-isoforms of 391, 419, and 479 amino acids, and two splice variants of the FUT11 gene, encoding for two related alpha-l-fucosyltransferases of 476 and 492 amino acids. The FUT10 and FUT11 appeared 830 million years ago, whereas the other(More)
The underlying causes of type I congenital disorders of glycosylation (CDG I) have been shown to be mutations in genes encoding proteins involved in the biosynthesis of the dolichyl-linked oligosaccharide (Glc(3)Man(9)GlcNAc(2)-PP-dolichyl) that is required for protein glycosylation. Here we describe a CDG I patient displaying gastrointestinal problems but(More)
Large, free polymannose oligosaccharides generated during glycoprotein biosynthesis rapidly appear in the cytosol of HepG2 cells where they undergo processing by a cytosolic endo H-like enzyme and a mannosidase to yield the linear isomer of Man5GlcNAc (Man[alpha 1-2]Man[alpha 1-2]Man[alpha 1-3][Man alpha 1-6]Man[beta 1-4] GlcNAc). Here we have examined the(More)
BACKGROUND During mammalian protein N-glycosylation, 20% of all dolichol-linked oligosaccharides (LLO) appear as free oligosaccharides (fOS) bearing the di-N-acetylchitobiose (fOSGN2), or a single N-acetylglucosamine (fOSGN), moiety at their reducing termini. After sequential trimming by cytosolic endo beta-N-acetylglucosaminidase (ENGase) and Man2c1(More)
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(More)
BACKGROUND In type I congenital disorders of glycosylation (CDG I), proteins necessary for the biosynthesis of the lipid-linked oligosaccharide (LLO) required for protein N-glycosylation are defective. A deficiency in guanosine diphosphate-mannose: GlcNAc(2)-PP-dolichol mannosyltransferase-1 (MT-1) causes CDG Ik (OMIM 608540), and only five patients, with(More)
Recently, the role of N-linked glycans in the process of ERAD (endoplasmic reticulum-associated degradation) of proteins has been widely recognized. In the present study, we attempted to delineate further the sequence of events leading from a fully glycosylated soluble protein to its deglycosylated form. Degradation intermediates of a truncated form of(More)