Evdonin A L, Tsupkina N V, Konstantinova I M, Medvedeva N D
Institute of Cytology, Russian Academy of Sciences, St. Petersburg.
Tsitologiia. 1999;41(10):895-9.
The intracellular proteasome distribution in A-431 cells was shown using methods of cell fractionation and immunofluorescence. In growing cells the distribution of proteasomes was EGF-dependent. In unstimulated cells and within 30 min of EGF treatment, proteasomes were localized in the cytoplasm and nuclei, but not on the plasma membrane. After 30 min of EGF treatment they were observed on the plasma membrane as well. In A-431 cells cultivated for 24 h in the medium with a lowered serum concentration, proteasomes were detected on the plasma membrane already in unstimulated cells. It is suggested that dephosphorylation of the EGF receptor and signalling proteins in unstimulated cells may depend on the proteolytic activity of proteasomes.
通过细胞分级分离和免疫荧光法展示了A-431细胞内蛋白酶体的分布情况。在生长的细胞中，蛋白酶体的分布依赖于表皮生长因子（EGF）。在未受刺激的细胞以及EGF处理30分钟内，蛋白酶体定位于细胞质和细胞核中，但不在质膜上。EGF处理30分钟后，在质膜上也能观察到它们。在血清浓度降低的培养基中培养24小时的A-431细胞中，在未受刺激的细胞中质膜上就已检测到蛋白酶体。有人提出，未受刺激的细胞中EGF受体和信号蛋白的去磷酸化可能依赖于蛋白酶体的蛋白水解活性。
