PDF(Pubmed)
Abstract：
The cell cortex is a dynamic assembly formed by the plasma membrane and underlying cytoskeleton. As the main determinant of cell shape, the cortex ensures its integrity during passive and active deformations by adapting cytoskeleton topologies through yet poorly understood mechanisms. The spectrin meshwork ensures such adaptation in erythrocytes and neurons by adopting different organizations. Erythrocytes rely on triangular-like lattices of spectrin tetramers, whereas in neurons they are organized in parallel, periodic arrays. Since spectrin is ubiquitously expressed, we exploited Expansion Microscopy to discover that, in fibroblasts, distinct meshwork densities co-exist. Through biophysical measurements and computational modeling, we show that the non-polarized spectrin meshwork, with the intervention of actomyosin, can dynamically transition into polarized clusters fenced by actin stress fibers that resemble periodic arrays as found in neurons. Clusters experience lower mechanical stress and turnover, despite displaying an extension close to the tetramer contour length. Our study sheds light on the adaptive properties of spectrin, which participates in the protection of the cell cortex by varying its densities in response to key mechanical features.
摘要：
细胞皮层是由质膜和下层细胞骨架形成的动态组装。作为细胞形状的主要决定因素，在被动和主动变形过程中，皮质通过尚未了解的机制来适应细胞骨架拓扑结构，从而确保其完整性。光谱网通过采用不同的组织来确保红细胞和神经元的这种适应。红细胞依赖于光谱四聚体的三角形晶格，而在神经元中，它们是平行组织的，周期数组。由于血影蛋白普遍表达，我们利用扩展显微镜来发现，在成纤维细胞中，不同的网孔密度共存。通过生物物理测量和计算建模，我们证明了非偏振光谱网，在肌动球蛋白的干预下，可以动态过渡到由肌动蛋白应力纤维包围的极化簇，这些纤维类似于神经元中的周期性阵列。集群经历较低的机械应力和营业额，尽管显示接近四聚体轮廓长度的延伸。我们的研究揭示了光谱的自适应特性，它通过响应关键机械特征而改变其密度来参与细胞皮质的保护。
