Dwyer-Nield L D, Miller A C, Neighbors B W, Dinsdale D, Malkinson A M
Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado Health Sciences Center, Denver 80262, USA.
Am J Physiol. 1996 Apr;270(4 Pt 1):L526-34. doi: 10.1152/ajplung.1996.270.4.L526.
Brief exposure to 12-O-tetradecanoylphorbol 13-acetate (TPA) caused a uniformly flattened population of mouse lung epithelial cells to become more heterogeneous; some cells rounded up, and others detached to overlap with flatter cells. Actin stress fiber organization was disrupted, and F-actin accumulated in lemellipodia. Vinculin dissociated from the focal adhesion plaques to diffuse throughout the cytoplasm. Inhibition of protein kinase C (PKC) activity blocked these effects of TPA. After 8 h of TPA exposure, actin filaments reassembled and vinculin again localized to the cell periphery. Calpain inhibition attenuated the decrease of PKC-alpha protein and PKC activity from the membrane fraction, and prevented the redistribution of cytoskeletal elements. Talin immunostaining was widespread throughout control cells but was localized to the periphery 8 h after treatment with TPA or with inhibitors of PKC and calpain. Both vinculin and talin concentrations increased with prolonged TPA treatment. PKC-zeta and calpain II were not appreciably affected by TPA exposure. Translocation of PKC-alpha to the membrane, followed by its calpain-induced downmodulation, is apparently required for the reversible pattern of cytoskeletal changes caused by TPA.
短暂暴露于12 - O -十四烷酰佛波醇 - 13 - 乙酸酯（TPA）会使原本均匀扁平的小鼠肺上皮细胞群体变得更加异质化；一些细胞变圆，另一些细胞脱离并与较扁平的细胞重叠。肌动蛋白应力纤维组织被破坏，F -肌动蛋白在片状伪足中积累。纽蛋白从粘着斑解离并扩散到整个细胞质中。蛋白激酶C（PKC）活性的抑制阻断了TPA的这些作用。TPA暴露8小时后，肌动蛋白丝重新组装，纽蛋白再次定位于细胞周边。钙蛋白酶抑制减弱了膜组分中PKC -α蛋白的减少和PKC活性，并阻止了细胞骨架成分的重新分布。在对照细胞中，踝蛋白免疫染色广泛分布，但在用TPA或PKC和钙蛋白酶抑制剂处理8小时后定位于周边。随着TPA处理时间延长，纽蛋白和踝蛋白浓度均增加。TPA暴露对PKC -ζ和钙蛋白酶II没有明显影响。TPA引起的细胞骨架变化的可逆模式显然需要PKC -α向膜的转位，随后是其钙蛋白酶诱导的下调。
