Properties of baby-hamster kidney (BHK) cells treated with Swainsonine, an inhibitor of glycoprotein processing. Comparison with ricin-resistant BHK-cell mutants.
نویسندگان
چکیده
Baby-hamster kidney (BHK) cells were grown continuously in long-term monolayer culture in the presence of Swainsonine, an inhibitor of alpha-mannosidase II, a processing enzyme involved in glycoprotein biosynthesis. The asparagine-linked oligosaccharides (N-glycans) were isolated from Pronase-digested cells by gel filtration, ion-exchange chromatography and affinity chromatography on concanavalin A--Sepharose and lentil lectin--Sepharose. The major N-glycans, analysed by 500 MHz 1H-n.m.r. spectroscopy, were identified as hybrid structures containing five mannose residues and neutral high-mannose N-glycans. The major hybrid species contained a core-substituted fucose alpha(1----6) residue and a NeuNAc alpha(2----3)Gal beta(1----4)GlcNAc terminal sequence; smaller amounts of non-sialylated and non-fucosylated hybrid structures were also detected. Swainsonine-treated cells also produced neutral oligosaccharides containing a single reducing N-acetylglucosamine residue substituted with polymannose sequences. The glycopeptide composition of Swainsonine-treated BHK cells resembles closely that of the ricin-resistant BHK cell mutant, RicR21 [P. A. Gleeson, J. Feeney and R. C. Hughes (1985) Biochemistry 24, 493-503], except the hybrid structures of RicR21 cells contain three, not five, mannose residues. Like RicR21 cells, Swainsonine-treated BHK cells showed a greatly increased resistance to ricin cytotoxicity, but not to modeccin, another galactose-binding lectin. These effects were readily reversed on removal of Swainsonine and growth in normal medium.
منابع مشابه
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The effects of the toxic lectins, ricin and modeccin, on baby hamster kidney (BHK) cells have been compared. Modeccin is about 20-50 times more toxic to BHK cells than ricin. Binding studies showed that there are 10(5) to 2 X 10(5) modeccin binding sites/cell compared with approximately 10(7) binding sites for ricin. Inhibition studies with galactosides indicate that both N- and O-glycans with ...
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عنوان ژورنال:
- The Biochemical journal
دوره 233 3 شماره
صفحات -
تاریخ انتشار 1986