Inhibition of N-linked glycosylation of P-glycoprotein by tunicamycin results in a reduced multidrug resistance phenotype.
Inhibition of N-linked glycosylation of P-glycoprotein by tunicamycin results in a reduced multidrug resistance phenotype.
复制标题
DOI：
10.1038/bjc.1995.133
复制
发表时间：
1995-04
影响因子：
8.8
通讯作者：
Summerhayes, I C
中科院分区：
文献类型：
--
作者：
Kramer, R;Weber, T K;Arceci, R;Ramchurren, N;Kastrinakis, W V;Steele, G Jr;Summerhayes, I C
发现与细胞系中不存在多药耐药（MDR）表型相关的P-糖蛋白（P-gp）糖基化改变的特征促使研究评估翻译后加工在功能性建立P-gp外排泵中的作用。本研究中使用的克隆A细胞系显示出由高组成性P-gp表达水平介导的强MDR表型。克隆A细胞与衣霉素孵育不同时间导致柔红霉素蓄积呈时间依赖性增加，反映P-gp功能降低。用维拉帕米进行的平行实验未导致克隆A细胞中P-gp功能丧失。通过FACS分析、蛋白质印迹分析和表面碘化P-gp的免疫沉淀确定暴露于衣霉素后表面相关P-gp减少。此外，从32 P-正磷酸盐标记的细胞的P-gp的免疫沉淀证明减少与衣霉素暴露相关的P-gp的磷酸化。从这些研究中，我们得出结论，糖基化的P-gp需要建立细胞MDR表型。
Characterisation of altered glycosylation of P-glycoprotein (P-gp) found associated with the absence of a multidrug resistance (MDR) phenotype in cell lines prompted an investigation to assess the role of post-translational processing in establishing P-gp efflux pump functionally. The clone A cell line used in this study displays a strong MDR phenotype mediated by high constitutive levels of expression of P-gp. Incubation of clone A cells with tunicamycin for different periods resulted in a time-dependent increase in daunorubicin accumulation, reflecting a reduction in P-gp function. Parallel experiments conducted with verapamil resulted in no loss of P-gp functionality in clone A cells. Reduction in surface-associated P-gp following exposure to tunicamycin was established by FACS analysis, Western blot analysis and immunoprecipitation of surface-iodinated P-gp. In addition, immunoprecipitation of P-gp from 32P-orthophosphate-labelled cells demonstrated reduced phosphorylation of P-gp associated with tunicamycin exposure. From these studies we conclude that glycosylation of P-gp is required to establish the cellular MDR phenotype.