Analysis of actin filament network organization in lamellipodia by comparing experimental and simulated images
Analysis of actin filament network organization in lamellipodia by comparing experimental and simulated images
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DOI：
10.1242/jcs.03379
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发表时间：
2007-04-15
影响因子：
4
通讯作者：
Verkhovsky, Alexander B.
中科院分区：
文献类型：
--
作者：
Schaub, Sebastien;Meister, Jean-Jacques;Verkhovsky, Alexander B.
细胞迁移过程中片状伪足的形成依赖于肌动蛋白网络的组装。组装机制，树突状细丝分支的基础上，已在体外系统中重建的研究，但很少有人知道的动态和结构特性的肌动蛋白网络在迁移细胞的板状伪足。长丝的长度和取向难以在光学或电子显微镜图像中直接测量，因为高长丝密度和单个长丝的重叠。在这里，我们使用的光学图像的不均匀性的板状伪足提取信息的结构和动力学特性的基础肌动蛋白网络。为了确定网络的图像特征和属性之间的关系，我们进行了模拟肌动蛋白网络组装，基于假设的随机分支和盖帽的细丝，并产生计算的“荧光”和“电子显微镜”图像的模拟网络。通过改变模拟参数，特别是肌动蛋白丝的密度，长度和方向，我们密切再现的对比度和特征的对角线上的十字形图案中观察到的实验光学图像。因此，将模拟网络的图像与实验图像相匹配，使我们能够估计片状伪足中肌动蛋白丝网络的参数。
Protrusion of lamellipodia during cell migration depends on the assembly of actin network. The assembly mechanism, based on dendritic filament branching, has been investigated in reconstituted in vitro systems, but little is known about the dynamical and structural properties of the actin network in the lamellipodia of migrating cells. The length and orientation of filaments are difficult to measure directly in either optical or electron microscopy images because of the high filament density and overlapping of individual filaments. Here, we use the non-uniformity of optical images of the lamellipodia to extract information about the structural and dynamical properties of the underlying actin network. To determine the relationship between the image features and the properties of the network, we performed simulations of actin network assembly, based on the hypothesis of stochastic branching and capping of filaments, and produced computed 'fluorescence' and 'electron microscopy' images of the simulated network. By varying simulation parameters, in particular the actin filament density, length and orientation, we closely reproduced the contrast and the characteristic diagonal criss-cross pattern observed in the experimental optical images. Thus, matching the images of the simulated network to the experimental images allowed us to estimate parameters of actin filament network in lamellipodia.