Lanoix J, Paiement J
Département d'Anatomie, Faculté de Médecine, Université de Montréal, Québec, Canada.
Cancer Lett. 1995 Nov 27;98(1):1-8.
The fusion capacity of rough endoplasmic reticulum membranes isolated from dissected liver tumor nodules of aflatoxin-treated rats was determined by cell free assay to be greater than that of homologous membranes from control liver. In a first attempt to understand the reason for this difference we compared the content of ras-related proteins in rough microsomal fractions and other cell fractions of both dissected tumor nodules and control liver. Using [alpha-32P]GTP blot overlay and densitometric analysis, homogenate, Golgi and rough endoplasmic reticulum fractions from dissected tumor nodules were observed to contain increased amounts of [alpha-32P]GTP binding to ras-related proteins when compared to homologous control fractions. Western blot analysis indicated that ras content was also increased in the tumor fractions. [alpha-32P]GTP-blot overlay using double-dimensional SDS-polyacrylamide gel electrophoresis confirmed quantitative differences in the amount of [alpha-32P]GTP binding to ras-related proteins between fractions from tumor and control tissues and indicated a surprising number of such proteins in each fraction. The data suggest that the changes in ras-related proteins could, in part, account for the enhanced GTP-dependent fusion capacity observed for the tumor-derived membranes.
通过无细胞分析测定，从经黄曲霉毒素处理的大鼠解剖肝肿瘤结节中分离出的粗面内质网膜的融合能力大于来自对照肝脏的同源膜。为了初步了解这种差异的原因，我们比较了解剖的肿瘤结节和对照肝脏的粗微粒体部分及其他细胞部分中与ras相关蛋白的含量。使用[α-32P]GTP印迹覆盖和光密度分析，与同源对照部分相比，观察到解剖肿瘤结节的匀浆、高尔基体和粗面内质网部分中与ras相关蛋白结合的[α-32P]GTP量增加。蛋白质印迹分析表明肿瘤部分中的ras含量也增加。使用二维SDS-聚丙烯酰胺凝胶电泳进行的[α-32P]GTP印迹覆盖证实了肿瘤和对照组织部分之间与ras相关蛋白结合的[α-32P]GTP量的定量差异，并表明每个部分中存在数量惊人的此类蛋白。数据表明，与ras相关蛋白的变化可能部分解释了观察到的肿瘤来源膜增强的GTP依赖性融合能力。
