Mechanism of inhibition of protein glycosylation by the antiviral sugar analogue 2-deoxy-2-fluoro-D-mannose: inhibition of synthesis of man(GlcNAc)2-PP-Dol by the guanosine diphosphate ester.
2-Deoxy-2-fluoro-D-mannose (2FMan), an antiviral mannose analogue, inhibited the dolichol cycle of protein glycosylation. To specifically inhibit oligosaccharide-lipid synthesis, and not (viral) protein synthesis in influenza virus infected cells, the addition of guanosine to the 2FMan-treated cells was required. Under these conditions an early step in the assembly of the oligosaccharide-lipid was inhibited, and as a consequence, the glycosylation of proteins was strongly inhibited. Low-molecular-weight, lipid-linked oligosaccharides accumulated in cells treated with 2FMan plus guanosine, although dolichol phosphate (Dol-P) and GDP-Man were still present in the treated cells, and membranes from these cells were not defective in assembly of lipid-linked oligosaccharides. Thus, the presence of a soluble inhibitor of oligosaccharide-lipid assembly in these cells was postulated, and GDP-2FMan and UDP-2FMan, two metabolites found in 2FMan-treated cells, were synthesized and used to study in cell-free systems the inhibition of oligosaccharide-lipid assembly. GDP-2FMan inhibited the synthesis of Man(GlcNAc)2-PP-Dol from (GlcNAc)2-PP-Dol and GDP-Man, and in addition, it caused a trapping of Dol-P as 2FMan-P-Dol, whereas UDP-2FMan only inhibited Glc-P-Dol synthesis. However, it is probable that neither trapping of Dol-P nor inhibition of Glc-P-Dol synthesis by UDP-2FMan contributed to inhibition of protein glycosylation in cells treated with 2FMan. Incorporation of 2FMan from GDP-2FMan or UDP-2FMan into dolichol diphosphate linked oligosaccharides and interference of GDP-2FMan with the latter steps of assembly of the dolichol diphosphate linked oligosaccharide could not be shown.(ABSTRACT TRUNCATED AT 250 WORDS)
D000818:Animals; D002472:Cell Transformation, Viral; D002474:Cell-Free System; D002642:Chick Embryo; D006023:Glycoproteins / Q000096:biosynthesis*; D006150:Guanine Nucleotides / Q000494:pharmacology*; D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology*; D009980:Influenza A virus / Q000235:genetics; D007425:Intracellular Membranes / Q000378:metabolism; D007700:Kinetics; D008861:Microsomes / Q000378:metabolism; D009844:Oligosaccharides / Q000096:biosynthesis; D011105:Polyisoprenyl Phosphate Sugars / Q000096:biosynthesis*; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D012210:Rhamnose / Q000031:analogs & derivatives* / Q000494:pharmacology
D006023:Glycoproteins; D006150:Guanine Nucleotides; D009844:Oligosaccharides; D011105:Polyisoprenyl Phosphate Sugars; D006153:Guanosine Diphosphate; C017190:2-deoxy-2-fluoromannose; C048079:guanosine diphosphate 2-deoxy-2-fluoromannose ester; D012210:Rhamnose