The dissipative contribution of myosin II in the cytoskeleton dynamics of myoblasts
The dissipative contribution of myosin II in the cytoskeleton dynamics of myoblasts
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DOI：
10.1007/s00249-004-0447-7
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发表时间：
2005-05-01
影响因子：
2
通讯作者：
Gallet, F
中科院分区：
文献类型：
--
作者：
Balland, M;Richert, A;Gallet, F
我们已经确定了单个细胞的肌动蛋白网络的微观流变学反应。我们用光钳对结合在C2成肌细胞肌动蛋白网络上的微球施加振荡力，并测量了诱导细胞变形的幅度和相移。对于没有扰动的单胞，我们证明了弹性和损耗模数G‘和G’表现为频率f(0.01<；f<；50赫兹)的幂函数f(α)和f(β)，α和β在0.15-0.35范围内。这表明，单个电池中的耗散机制涉及到广泛和连续的驰豫时间分布。加入肌球蛋白II活性的抑制剂Blebbistatin后，G‘的指数下降到约0.10，G’‘在0.01<；f<；10赫兹时大致保持不变。与对照实验相比，肌动蛋白网络看起来不那么僵硬，耗散也更少。这与肌球蛋白II对肌动蛋白ATPase的抑制和滑行能力的降低是一致的。哀叹。在这个频率范围内，肌动球蛋白的活性似乎是细胞适应外部机械压力的基本机制。
We have determined the microrheological response of the actin meshwork for individual cells. We applied oscillating forces with an optical tweezer to a micrometric bead specifically bound to the actin meshwork of C2 myoblasts, and measured the amplitude and phase shift of the induced cell deformation. For a non-perturbed single cell, we have shown that the elastic and loss moduli G' and G '' behave as power laws f(alpha) and f(beta) of the frequency f (0.01< f < 50 Hz), alpha and beta being in the range 0.15 - 0.35. This demonstrates that the dissipation mechanisms in a single cell involve a broad and continuous distribution of relaxation times. After adding blebbistatin, an inhibitor of myosin II activity, the exponent of G' decreases to about 0.10, and G '' becomes roughly constant for 0.01< f< 10 Hz. The actin meshwork appears less rigid and less dissipative than in the control experiment. This is consistent with an inhibition of ATPase and reduction of the gliding mobility of myosin II on actin. laments. In this frequency range, the actomyosin activity appears as an essential mechanism allowing the cell to adapt to an external mechanical stress.