Dynamic and structural signatures of lamellar actomyosin force generation.
Dynamic and structural signatures of lamellar actomyosin force generation.
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层状肌球蛋白力产生的动态和结构特征。
DOI：
10.1091/mbc.e10-11-0891
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发表时间：
2011-04-15
影响因子：
3.3
通讯作者：
Gardel ML
中科院分区：
文献类型：
--
作者：
Aratyn-Schaus Y;Oakes PW;Gardel ML
在不同的张力水平的层状肌动蛋白细胞骨架的动力学和组织进行了鉴定。研究了应力纤维组装的力相关步骤。细胞外基质上的细胞牵引力的调节对于细胞粘附、迁移、增殖和分化至关重要。在贴壁细胞中观察到从收缩性板层网络到应力纤维的多种板层肌动蛋白组织。虽然层状组织被认为反映了细胞力产生的程度，但对层状肌动蛋白细胞骨架的物理行为缺乏了解。为了阐明这些属性，我们可视化的肌动球蛋白动力学和组织在U2 OS细胞在广泛的力量。在低力，收缩性板层网络占主导地位，力的产生与肌动球蛋白逆行流动动力学与组织的名义变化密切相关。层状网络在快速的时间尺度上建立了约60%的细胞张力。在高的力，重组成应力纤维的层状网络的结果在细胞张力在较慢的时间尺度适度的变化。随着应力纤维的建立和张力的增加，肌球蛋白带间距减小，α-辅肌动蛋白带形成。在软基质上，层状网络产生的力不受影响，而依赖于张力的应力纤维组装被废除。这些数据阐明了动态和结构的肌动球蛋白细胞骨架在不同水平的张力和定量模型的细胞和组织力学奠定了基础。
The dynamics and organization of the lamellar actin cytoskeleton at different levels of tension are identified. The force-dependent steps of stress fiber assembly are studied. The regulation of cellular traction forces on the extracellular matrix is critical to cell adhesion, migration, proliferation, and differentiation. Diverse lamellar actin organizations ranging from contractile lamellar networks to stress fibers are observed in adherent cells. Although lamellar organization is thought to reflect the extent of cellular force generation, understanding of the physical behaviors of the lamellar actin cytoskeleton is lacking. To elucidate these properties, we visualized the actomyosin dynamics and organization in U2OS cells over a broad range of forces. At low forces, contractile lamellar networks predominate and force generation is strongly correlated to actomyosin retrograde flow dynamics with nominal change in organization. Lamellar networks build ∼60% of cellular tension over rapid time scales. At high forces, reorganization of the lamellar network into stress fibers results in moderate changes in cellular tension over slower time scales. As stress fibers build and tension increases, myosin band spacing decreases and α-actinin bands form. On soft matrices, force generation by lamellar networks is unaffected, whereas tension-dependent stress fiber assembly is abrogated. These data elucidate the dynamic and structural signatures of the actomyosin cytoskeleton at different levels of tension and set a foundation for quantitative models of cell and tissue mechanics.