Nuclear envelope acts as a calcium barrier in C6 glioma cells
Nuclear envelope acts as a calcium barrier in C6 glioma cells
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DOI：
10.1006/bbrc.1996.0105
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发表时间：
1996-01-17
影响因子：
3.1
通讯作者：
Lee, CY
中科院分区：
文献类型：
--
作者：
Kong, SK;Tsang, D;Lee, CY
利用激光共聚焦扫描显微镜研究了 C6 胶质瘤细胞胞浆和细胞核内的细胞内游离钙 ([Ca2+]i) 的时间和空间变化，以评估目前 Ca2+ 离子通过扩散自由通过核孔的观点。我们的结果表明，局部胞质 Ca2+ 释放；其呈泡状，以 0.35 +/- 0.07 微米/秒的表观扩散速率扩散（n = 44）。此释放之后是在静息阶段立即吸收 Ca2+。用毒胡萝卜素（一种微粒体 Ca2+-ATP 酶抑制剂）处理后，从某些核热区和核膜中释放出核 Ca2+。大部分释放的核 Ca2+ 局限于核边界，但观察到 Ca2+ 向细胞质缓慢迁移。该Ca2+释放的表观扩散速率为0.015μm/秒。相比之下，向核内扩散的扩散速率为0.04μm/秒。根据这些扩散速率和其他实验证据，我们得出结论，Ca2+ 在核细胞溶质界面的运动不仅仅是一个简单的扩散过程，界面是 Ca2+ 运动的障碍。 (C) 1996 学术出版社
The temporal and spatial changes of intracellular free calcium ([Ca2+]i) within the cytosol and nucleis of C6 glioma cells have been investigated with laser confocal scanning microscopy to evaluate the current view that Ca2+ ions pass freely through nuclear pores by diffusion. Our results indicate that localized cytosolic Ca2+ release; which appeared as puffs, spread with an apparent diffusion rate of 0.35 +/- 0.07 mu m/sec (n = 44). This release was followed by an immediate Ca2+ uptake at the resting stage. Following the treatment with thapsigargin, an inhibitor of microsomal Ca2+-ATPase, release of nuclear Ca2+ from certain nuclear hot zones and nuclear envelope was obtained. Most of the nuclear Ca2+ released were confined to the nuclear boundary, but a slow migration of Ca2+ towards the cytosol was observed. The apparent diffusion rate of this Ca2+ release is 0.015 mu m/sec. By contrast, the inward spread into nucleus occurred with a diffusion rate of 0.04 mu m/sec. From these diffusion rates and other experimental evidence, we conclude that the movement of Ca2+ at the nucleocytosolic interface is more than a simple diffusion process and the interface is a barrier to Ca2+ movement. (C) 1996 Academic Press, Inc.