Fischer-Friedrich Elisabeth, Toyoda Yusuke, Cattin Cedric J, Müller Daniel J, Hyman Anthony A, Jülicher Frank
Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany; Max Planck Institute for the Physics of Complex Systems, Dresden, Germany.
Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany; Institute of Life Science, Kurume University, Kurume, Japan.
Biophys J. 2016 Aug 9;111(3):589-600. doi: 10.1016/j.bpj.2016.06.008.
The cell cortex is a key structure for the regulation of cell shape and tissue organization. To reach a better understanding of the mechanics and dynamics of the cortex, we study here HeLa cells in mitosis as a simple model system. In our assay, single rounded cells are dynamically compressed between two parallel plates. Our measurements indicate that the cortical layer is the dominant mechanical element in mitosis as opposed to the cytoplasmic interior. To characterize the time-dependent rheological response, we extract a complex elastic modulus that characterizes the resistance of the cortex against area dilation. In this way, we present a rheological characterization of the cortical actomyosin network in the linear regime. Furthermore, we investigate the influence of actin cross linkers and the impact of active prestress on rheological behavior. Notably, we find that cell mechanics values in mitosis are captured by a simple rheological model characterized by a single timescale on the order of 10 s, which marks the onset of fluidity in the system.
细胞皮层是调节细胞形状和组织组织的关键结构。为了更好地理解皮层的力学和动力学，我们在此研究处于有丝分裂期的HeLa细胞作为一个简单的模型系统。在我们的实验中，单个圆形细胞在两个平行板之间动态压缩。我们的测量表明，与细胞质内部相反，皮层是有丝分裂中主要的力学元件。为了表征随时间变化的流变响应，我们提取了一个复弹性模量，该模量表征皮层对面积扩张的阻力。通过这种方式，我们在线性区域对皮层肌动球蛋白网络进行了流变学表征。此外，我们研究了肌动蛋白交联剂的影响以及主动预应力对流变行为的影响。值得注意的是，我们发现有丝分裂中的细胞力学值可以通过一个简单的流变模型来捕捉，该模型的特征是一个约10秒的单一时间尺度，这标志着系统中流动性的开始。
