Dynamical organization of the cytoskeletal cortex probed by micropipette aspiration
Dynamical organization of the cytoskeletal cortex probed by micropipette aspiration
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DOI：
10.1073/pnas.0913669107
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发表时间：
2010-08-31
影响因子：
11.1
通讯作者：
Sens, Pierre
中科院分区：
文献类型：
--
作者：
Brugues, Jan;Maugis, Benoit;Sens, Pierre
基于泡状结构的细胞运动是通过大的球形膜突起（“泡”）的连续膨胀和收缩以及与底物的黏附来进行的。除了在运动中的作用外，细胞泡还是细胞骨架皮层与质膜之间动态相互作用的一个显著例证。在这里，我们研究了溶组织内阿米巴在微吸管受限几何形状中的基于泡状结构的运动。我们构建了一个通用的理论模型，该模型将质膜下肌动蛋白皮层的聚合与皮层中肌球蛋白产生的收缩应力以及应力诱导的膜 - 皮层黏附失效相结合。决定细胞对微吸管吸力响应的一个主要参数是稳定的皮层厚度，它由肌动蛋白的聚合和解聚所控制。其他相关的物理参数可以组合成两个特征皮层厚度，在这两个厚度下，肌球蛋白应力（i）平衡吸力压力，（ii）引发膜 - 皮层解离。通过比较这三个厚度，我们提出了一个微吸管内细胞运动的通用相图。特别是，我们从理论上预测并通过实验验证了在明确界定的微吸管吸力压力范围内存在跳跃式和振荡式运动。
Bleb-based cell motility proceeds by the successive inflation and retraction of large spherical membrane protrusions ("blebs") coupled with substrate adhesion. In addition to their role in motility, cellular blebs constitute a remarkable illustration of the dynamical interactions between the cytoskeletal cortex and the plasma membrane. Here we study the bleb-based motions of Entamoeba histolytica in the constrained geometry of a micropipette. We construct a generic theoretical model that combines the polymerization of an actin cortex underneath the plasma membrane with the myosin-generated contractile stress in the cortex and the stress-induced failure of membrane-cortex adhesion. One major parameter dictating the cell response to micropipette suction is the stationary cortex thickness, controlled by actin polymerization and depolymerization. The other relevant physical parameters can be combined into two characteristic cortex thicknesses for which the myosin stress (i) balances the suction pressure and (ii) provokes membrane-cortex unbinding. We propose a general phase diagram for cell motions inside a micropipette by comparing these three thicknesses. In particular, we theoretically predict and experimentally verify the existence of saltatory and oscillatory motions for a well-defined range of micropipette suction pressures.