Active fluctuation in the cortical cytoskeleton observed by high-speed live-cell scanning probe microscopy
Active fluctuation in the cortical cytoskeleton observed by high-speed live-cell scanning probe microscopy
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高速活细胞扫描探针显微镜观察到皮质细胞骨架的主动波动
DOI：
10.1016/j.actbio.2011.06.013
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
K.Kawabata
中科院分区：
文献类型：
--
作者：
K.Tamura;T.Mizutani;H.Haga;K.Kawabata
我们通过扫描探针显微镜（SPM）分析细胞骨架内源性成分的运动，研究了活细胞皮层细胞骨架的动力学。我们对活细胞中SPM可视化的微颗粒进行了分子表征，并通过颗粒跟踪分析了这些微颗粒的运动。SPM和荧光显微镜同时观察发现，微颗粒不仅招募肌动蛋白，还招募了能与肌动蛋白丝结合的接触蛋白。这表明微颗粒处有肌动蛋白丝的缩聚，这使我们将其识别为“细胞骨架微结构域”。高速SPM观察和粒子跟踪分析表明，这些细胞骨架微域在秒的时间尺度上表现出随机行走的扩散波动。抑制驱动肌动蛋白丝的分子运动肌球蛋白II，导致微结构域的亚扩散波动。这些结果可以用肌凝蛋白II随机驱动肌动蛋白丝的纵向滑动和肌动蛋白丝在没有滑动时的弯曲运动来解释。细胞骨架微结构域的分析揭示了皮质细胞骨架的内在动力学。
We investigated the dynamics of the cortical cytoskeleton in living cells by analyzing the motion of the endogenous components of the cytoskeleton using scanning probe microscopy (SPM). We performed molecular characterization of the microgranules visualized by SPM in living cells and analyzed the motion of these microgranules via particle tracking. Simultaneous SPM and epifluorescence microscopy observations showed that the microgranules recruited not only actin but also cortactin, which can bind to actin filaments. This indicates condensation of actin filaments at microgranules, leading us to identify them as “cytoskeletal microdomains”. High-speed SPM observation and particle-tracking analysis showed that these cytoskeletal microdomains exhibit random walk-like diffusive fluctuations over a timescale of seconds. Inhibition of the molecular motor myosin II, which drives actin filaments, led to subdiffusive fluctuations of the microdomains. These results can be explained by longitudinal sliding of actin filaments stochastically driven by myosin II and the bending motion of the actin filaments in the absence of sliding. Analysis of the cytoskeletal microdomains thus revealed the intrinsic dynamics of the cortical cytoskeleton.