Time scale and other invariants of integrative mechanical behavior in living cells
Time scale and other invariants of integrative mechanical behavior in living cells
复制标题
DOI：
10.1103/physreve.68.041914
复制
发表时间：
2003-10-01
影响因子：
2.4
通讯作者：
Fredberg, JJ
中科院分区：
文献类型：
--
作者：
Fabry, B;Maksym, GN;Fredberg, JJ
在处理像细胞骨架这样复杂的系统时，我们需要组织原则，或者缺乏一个适合这些系统的经验框架。我们在这里报告了构成这样一个经验框架的细胞骨架行为的意想不到的不变量。我们在广泛的时间尺度内并使用各种生物干预措施测量了各种细胞类型的弹性和摩擦模量。在所有情况下，弹性应力在低于 300 Hz 的频率下占主导地位，仅随频率微弱增加，并且遵循幂律；没有明显的特征时间尺度。摩擦应力在低于 10 Hz 的频率下与弹性行为平行，但在较高频率下接近牛顿粘性行为。令人惊讶的是，所有数据都可以折叠到主曲线上，主曲线的存在意味着弹性应力和摩擦应力具有共同的基础机制。总而言之，这些发现定义了一个意想不到的综合框架，用于研究细胞体复杂微环境中的蛋白质相互作用，并且似乎对仅基于单独考虑的细胞骨架成分的基质综合机械行为的预测设定了限制。此外，这些观察结果与活细胞的细胞骨架表现为软玻璃状材料的假设一致，其中细胞骨架蛋白主要通过改变细胞骨架基质的有效温度来调节细胞机械特性。如果是这样，那么有效温度就成为细胞骨架变形、流动和重组能力的一个容易量化的决定因素。
In dealing with systems as complex as the cytoskeleton, we need organizing principles or, short of that, an empirical framework into which these systems fit. We report here unexpected invariants of cytoskeletal behavior that comprise such an empirical framework. We measured elastic and frictional moduli of a variety of cell types over a wide range of time scales and using a variety of biological interventions. In all instances elastic stresses dominated at frequencies below 300 Hz, increased only weakly with frequency, and followed a power law; no characteristic time scale was evident. Frictional stresses paralleled the elastic behavior at frequencies below 10 Hz but approached a Newtonian viscous behavior at higher frequencies. Surprisingly, all data could be collapsed onto master curves, the existence of which implies that elastic and frictional stresses share a common underlying mechanism. Taken together, these findings define an unanticipated integrative framework for studying protein interactions within the complex microenvironment of the cell body, and appear to set limits on what can be predicted about integrated mechanical behavior of the matrix based solely on cytoskeletal constituents considered in isolation. Moreover, these observations are consistent with the hypothesis that the cytoskeleton of the living cell behaves as a soft glassy material, wherein cytoskeletal proteins modulate cell mechanical properties mainly by changing an effective temperature of the cytoskeletal matrix. If so, then the effective temperature becomes an easily quantified determinant of the ability of the cytoskeleton to deform, flow, and reorganize.