Viscoelastic properties of vimentin compared with other filamentous biopolymer networks.
Viscoelastic properties of vimentin compared with other filamentous biopolymer networks.
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DOI：
10.1083/jcb.113.1.155
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发表时间：
1991-04
期刊：
影响因子：
--
通讯作者：
Schliwa M
中科院分区：
文献类型：
--
作者：
Janmey PA;Euteneuer U;Traub P;Schliwa M
脊椎动物细胞的细胞质含有三种不同的丝状生物聚合物，微管，微丝和中间丝。这三种纤维的基本结构元件分别是微管蛋白、肌动蛋白和波形蛋白或另一种相关中间纤维蛋白的线性聚合物。细胞质细丝的粘弹性可能与它们的生物学功能有关，因为它们的极端长度和棒状结构支配着细胞质的流变行为，并且当细胞被激活或开始移动时，它们的结构变化可能导致观察到的凝胶-溶胶转变。本文介绍了微管蛋白，肌动蛋白和波形蛋白聚合物的粘弹性的平行测量。三种类型的细胞质聚合物之间的流变学差异表明，不同类别的细丝在体内可能具有专门的作用。肌动蛋白形成在高应变下伸展的最高刚性的网络，这与细胞运动中的作用一致，其中稳定的突起可以响应于受控的细丝断裂而迅速变形。波形蛋白网络，以前没有被研究过的流变学方法，表现出一些不寻常的粘弹性不共享肌动蛋白或微管蛋白。它们在低应变下刚性较小（具有较低的剪切模量），但在高应变下硬化并抵抗断裂，这表明它们保持细胞完整性。F-肌动蛋白和波形蛋白之间的差异对于形成具有一系列特性的复合材料是最佳的，这些特性不能由单独的聚合物实现。微管不太可能单独对间期细胞流变学有显著贡献，但可能有助于稳定其他网络。
The cytoplasm of vertebrate cells contains three distinct filamentous biopolymers, the microtubules, microfilaments, and intermediate filaments. The basic structural elements of these three filaments are linear polymers of the proteins tubulin, actin, and vimentin or another related intermediate filament protein, respectively. The viscoelastic properties of cytoplasmic filaments are likely to be relevant to their biologic function, because their extreme length and rodlike structure dominate the rheologic behavior of cytoplasm, and changes in their structure may cause gel-sol transitions observed when cells are activated or begin to move. This paper describes parallel measurements of the viscoelasticity of tubulin, actin, and vimentin polymers. The rheologic differences among the three types of cytoplasmic polymers suggest possible specialized roles for the different classes of filaments in vivo. Actin forms networks of highest rigidity that fluidize at high strains, consistent with a role in cell motility in which stable protrusions can deform rapidly in response to controlled filament rupture. Vimentin networks, which have not previously been studied by rheologic methods, exhibit some unusual viscoelastic properties not shared by actin or tubulin. They are less rigid (have lower shear moduli) at low strain but harden at high strains and resist breakage, suggesting they maintain cell integrity. The differences between F-actin and vimentin are optimal for the formation of a composite material with a range of properties that cannot be achieved by either polymer alone. Microtubules are unlikely to contribute significantly to interphase cell rheology alone, but may help stabilize the other networks.