Myosin-II-Mediated Directional Migration of Dictyostelium Cells in Response to Cyclic Stretching of Substratum
Myosin-II-Mediated Directional Migration of Dictyostelium Cells in Response to Cyclic Stretching of Substratum
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DOI：
10.1016/j.bpj.2013.01.005
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发表时间：
2013-02-19
影响因子：
3.4
通讯作者：
Minami, Kazuyuki
中科院分区：
文献类型：
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作者：
Iwadate, Yoshiaki;Okimura, Chika;Minami, Kazuyuki
活细胞不断受到各种机械刺激，如剪切流、渗透压、基质硬度等。它们必须感知环境的机械方面并做出适当的反应以实现正常的细胞功能。粘附在基质上的细胞必须接收并响应来自基质的机械刺激，以决定它们的形状和/或迁移方向。响应弹性基质的循环拉伸，成纤维细胞和内皮细胞、骨肉瘤细胞和平滑肌细胞中的细胞内应力纤维垂直于拉伸方向重新排列，并且这些细胞的形状沿这个新方向延伸。在迁移盘基网柄菌细胞的情况下，循环拉伸调节细胞的迁移方向，而不是形状。细胞沿与拉伸方向垂直的方向迁移。然而，诱导定向迁移的分子机制仍然未知。在这里，我们使用微拉伸装置记录了循环拉伸下弹性基质上盘基网柄菌细胞中的绿色荧光蛋白（GFP）-肌球蛋白-II 动力学。重复拉伸诱导肌球蛋白 II 在细胞拉伸两侧均匀定位。尽管肌球蛋白 II 缺失细胞随机迁移，但表达不能水解 ATP 的肌球蛋白 II 变体的肌球蛋白 II 缺失细胞垂直于拉伸方向迁移。这些结果表明，盘基网柄菌属细胞在接受大应变的细胞部分处积聚肌球蛋白II，并且向与肌球蛋白II积聚部分不同的方向移动。这种迁移的极性产生不需要肌动球蛋白的收缩。
Living cells are constantly subjected to various mechanical stimulations, such as shear flow, osmotic pressure, and hardness of substratum. They must sense the mechanical aspects of their environment and respond appropriately for proper cell function. Cells adhering to substrata must receive and respond to mechanical stimuli from the substrata to decide their shape and/or migrating direction. In response to cyclic stretching of the elastic substratum, intracellular stress fibers in fibroblasts and endothelial, osteosarcoma, and smooth muscle cells are rearranged perpendicular to the stretching direction, and the shape of those cells becomes extended in this new direction. In the case of migrating Dictyostelium cells, cyclic stretching regulates the direction of migration, and not the shape, of the cell. The cells migrate in a direction perpendicular to that of the stretching. However, the molecular mechanisms that induce the directional migration remain unknown. Here, using a microstretching device, we recorded green fluorescent protein (GFP)-myosin-II dynamics in Dictyostelium cells on an elastic substratum under cyclic stretching. Repeated stretching induced myosin II localization equally on both stretching sides in the cells. Although myosin-II-null cells migrated randomly, myosin-II-null cells expressing a variant of myosin II that cannot hydrolyze ATP migrated perpendicular to the stretching. These results indicate that Dictyostelium cells accumulate myosin II at the portion of the cell where a large strain is received and migrate in a direction other than that of the portion where myosin II accumulated. This polarity generation for migration does not require the contraction of actomyosin.