Schlosser Florian, Rehfeldt Florian, Schmidt Christoph F
Third Institute of Physics-Biophysics, Georg August University, 37077 Göttingen, Germany.
Third Institute of Physics-Biophysics, Georg August University, 37077 Göttingen, Germany
Philos Trans R Soc Lond B Biol Sci. 2015 Feb 5;370(1661):20140028. doi: 10.1098/rstb.2014.0028.
Cells are sensitive to mechanical cues from their environment and at the same time generate and transmit forces to their surroundings. To test quantitatively forces generated by cells not attached to a substrate, we used a dual optical trap to suspend 3T3 fibroblasts between two fibronectin-coated beads. In this simple geometry, we measured both the cells' elastic properties and the force fluctuations they generate with high bandwidth. Cell stiffness decreased substantially with both myosin inhibition by blebbistatin and serum-starvation, but not with microtubule depolymerization by nocodazole. We show that cortical forces generated by non-muscle myosin II deform the cell from its rounded shape in the frequency regime from 0.1 to 10 Hz. The amplitudes of these forces were strongly reduced by blebbistatin and serum starvation, but were unaffected by depolymerization of microtubules. Force fluctuations show a spectrum that is characteristic for an elastic network activated by random sustained stresses with abrupt transitions.
细胞对来自其周围环境的机械信号敏感，同时也会产生并向周围环境传递力。为了定量测试未附着于基质的细胞所产生的力，我们使用了双光镊将3T3成纤维细胞悬浮于两颗包被纤连蛋白的珠子之间。在这种简单的结构中，我们测量了细胞的弹性特性以及它们以高带宽产生的力的波动。细胞刚度在受到肌球蛋白抑制剂blebbistatin抑制以及血清饥饿处理时均显著降低，但在受到诺考达唑介导的微管解聚处理时并未降低。我们发现，非肌肉肌球蛋白II产生的皮层力会在0.1至10 Hz的频率范围内使细胞从圆形变形。这些力的幅度在受到blebbistatin和血清饥饿处理时大幅降低，但不受微管解聚的影响。力的波动呈现出一种频谱，这是由随机持续应力激活并伴有突然转变的弹性网络所特有的。
