Prescott A R, Comerford J G, Magrath R, Lamb N J, Warn R M
School of Biological Sciences, University of East Anglia, Norwich, UK.
J Cell Sci. 1988 Mar;89 ( Pt 3):321-9. doi: 10.1242/jcs.89.3.321.
Increasing the intracellular magnesium concentration of PtK2 cells by 1 mM or more resulted in the disassembly of the interphase microtubule array over a period of 5 min after microinjection. This effect was found to be both transient and fully reversible, with the microtubule arrays reforming after further incubation. These effects were studied using immunofluorescence microscopy of fixed cells, and also in living cells using rhodamine-tubulin or rhodamine-conjugated anti-tubulin antibodies and image intensification and enhancement techniques. Simultaneously and accompanying the disassembly of the microtubule arrays the F-actin stress fibres also disappeared, usually leaving the peripheral and perinuclear F-actin microfilaments intact. In contrast, increasing intracellular magnesium appeared to have no effect on the vimentin-containing intermediate filaments of PtK2 cells. These effects on the cytoskeleton were specific to magnesium and could not be mimicked by either microinjection of injection buffer of equivalent ionic strength or sham injection. Raising the intracellular free calcium to the same extent resulted in the disassembly of the microtubule network, but appeared to have no effect on the F-actin stress fibres.
将PtK2细胞的细胞内镁浓度提高1 mM或更多，在显微注射后5分钟内会导致间期微管阵列解体。发现这种效应是短暂且完全可逆的，进一步孵育后微管阵列会重新形成。这些效应通过固定细胞的免疫荧光显微镜进行研究，也在活细胞中使用罗丹明 - 微管蛋白或罗丹明偶联的抗微管蛋白抗体以及图像增强技术进行研究。在微管阵列解体的同时，F - 肌动蛋白应力纤维也消失了，通常使外周和核周的F - 肌动蛋白微丝保持完整。相比之下，细胞内镁浓度的增加似乎对PtK2细胞中含波形蛋白的中间丝没有影响。这些对细胞骨架的影响是镁特有的，通过显微注射等离子强度的注射缓冲液或假注射都无法模拟。将细胞内游离钙提高到相同程度会导致微管网络解体，但似乎对F - 肌动蛋白应力纤维没有影响。
