Microfilament dynamics during HaCaT cell volume regulation
Microfilament dynamics during HaCaT cell volume regulation
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DOI：
10.1016/j.ejcb.2008.10.003
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发表时间：
2009-03-01
影响因子：
6.6
通讯作者：
Bereiter-Hahn, Juergen
中科院分区：
文献类型：
--
作者：
Blase, Christopher;Becker, Daniel;Bereiter-Hahn, Juergen
细胞体积是许多生理过程的重要参数，在许多细胞类型中受到密切调节。在这些细胞中，低渗介质引起的肿胀随后是离子驱动的调节性体积减少。在许多细胞类型中，这种调节体积的减少需要一个完整的肌动蛋白细胞骨架。因此，我们研究了HaCaT角化细胞在细胞肿胀和调节体积减少过程中肌动蛋白细胞骨架结构和聚合状态的变化。2 μ M细胞松弛素D破坏肌动蛋白细胞骨架可抑制HaCaT细胞的调节性体积减少。在低浓度细胞松弛素D （0.8 μ M, 305-250 mosM）存在下肿胀的细胞即使在去除细胞松弛素D后仍保持高体积。强直性的进一步降低（250-200 mosM）再次被达到体积的调节体积减少所抵消，该体积已在250 mosM时确定。相比之下，egfp -actin转染的HaCaT细胞在肿胀或调节体积减少期间，肌动蛋白细胞骨架形态未发生明显变化。然而，生化分析显示，总f -肌动蛋白水平在低渗发作后90s增加。低渗休克后，可溶肌动蛋白与不可溶肌动蛋白的比例也增加，这表明测量到的f -肌动蛋白的增加主要是由于重新聚合和形成短肌动蛋白细丝，即肌动蛋白低聚物。这些结果表明，在低渗处理后，肌动蛋白细胞骨架发生了快速重组。这种重组可以通过隔离或释放肌动蛋白相关蛋白间接影响低渗反应的信号传导，也可以通过肌动蛋白短丝与质膜离子通道的相互作用直接影响信号传导，并可能参与确定新的体积设定值。(C) 2008爱思唯尔有限公司版权所有。
Cell volume is an important parameter in many physiological processes, and is closely regulated in many cell types. In those cells, swelling induced by hypotonic media is followed by an ion-driven regulatory Volume decrease. In many cell types, this regulatory volume decrease requires an intact actin cytoskeleton. Therefore, we investigated the changes in the structure and polymerization state of the actin cytoskeleton in HaCaT keratinocytes during cell swelling and regulatory volume decrease. Disruption of the actin cytoskeleton by 2 mu M cytochalasin D inhibits regulatory volume decrease in HaCaT cells. Cells swollen in the presence of low concentrations of cytochalasin D (0.8 mu M, 305-250 mosM) keep the elevated volume even after cytochalasin D removal. A further decrease of tonicity (250-200 mosM) is again counteracted by regulatory volume decrease reaching the volume, which has been established at 250 mosM. In contrast, no visible changes occurred in actin cytoskeleton morphology of EGFP-actin-transfected HaCaT cells during swelling or regulatory volume decrease. However, biochemical analysis showed an increase in total F-actin levels 90 s after the onset of hypotonicity. The ratio of Triton-soluble to -insoluble actin also increased after hypotonic shock, suggesting that the measured increase in F-actin is primarily due to de novo polymerization and formation of short actin filaments, i.e., actin oligomers. These results show that a rapid reorganization of the actin cytoskeleton takes place after hypotonic treatment. This reorganization can influence signaling in response to hypotonicity either indirectly by means of sequestering or releasing actin-associated proteins, or directly by the interaction of short actin filaments with plasma membrane ion channels, and may be involved in determining a new volume set point. (C) 2008 Elsevier GmbH. All rights reserved.