多利醇
衣霉素
糖蛋白
糖基化
甘露糖
生物化学
氨基葡萄糖
生物合成
化学
低聚糖
凝胶电泳
酶
未折叠蛋白反应
内质网
作者
Yi He Ling,Michael T. Tseng,James I. Harty
出处
期刊:PubMed
日期:1989-01-01
卷期号:49 (1): 76-80
被引量:2
摘要
Rates of [3H]glucosamine and mannose incorporation into glycoproteins and dolichol-linked oligosaccharides in exponentially growing T-24 bladder cancer cells were examined after exposure to homoharringtonine (HHT). Two-h treatment of HHT (10 ng/ml) reduced [3H]glucosamine and mannose incorporation into the glycoproteins to 61% and 32% of controls. Concomitantly, respective sugar incorporation into dolichol-linked oligosaccharides was elevated 29% and 30% above control. The maximal inhibition of glycoprotein biosynthesis and stimulation of the lipid-linked oligosaccharides occurred within 2 to 4 h after exposure to 50 ng/ml of the drug. Prolonged drug exposure (greater than 8 h) resulted in generalized suppression of glycoprotein biosynthesis and lipid-linked oligosaccharide formation. The kinetic study indicated that the time course on reduction of glycoprotein biosynthesis and accumulation of dolichol-linked oligosaccharides paralleled the decline in protein synthesis. Further, the inhibition of glycoprotein synthesis and stimulation of dolichol-linked oligosaccharides were reversible 4 h after drug withdrawal. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis autoradiographic analysis of the [3H]mannose-labeled glycoprotein revealed no pronounced difference between HHT-treated and control cells. These data suggest that the inhibition of glycosylation results from combined decrease of acceptors for glycoprotein biosynthesis with a simultaneous accumulation of the dolichol-linked oligosaccharides. Collectively these data may account for many of the HHT-induced bioresponses.
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