Limiting Pool and Actin Architecture Controls Myosin Cluster Sizes in Adherent Cells.
Limiting Pool and Actin Architecture Controls Myosin Cluster Sizes in Adherent Cells.
复制标题
限制池和肌动蛋白结构控制贴壁细胞中的肌球蛋白簇大小。
DOI：
10.1101/2023.06.07.544121
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Gardel,MargaretL
中科院分区：
文献类型：
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作者：
Chou,Wen-Hung;Molaei,Mehdi;Wu,Huini;Oakes,PatrickW;Beach,JordanR;Gardel,MargaretL
肌动球蛋白细胞骨架产生机械力，为重要的细胞过程提供动力，如细胞迁移、细胞分裂和机械感应。肌动球蛋白自组装成可收缩的网络和束，这些网络和束是细胞中力产生和传递的基础。一个中心步骤是从肌球蛋白单体组装肌球蛋白II丝，其调控已被广泛研究。然而，肌球蛋白丝几乎总是在细胞皮质内以簇的形式存在。虽然最近的研究表征了细胞周边的簇成核动力学，但肌球蛋白簇如何在应力纤维上生长的特征仍然很差。在这里，我们利用U2 OS骨肉瘤细胞系与内源性标记的肌球蛋白II来测量肌球蛋白簇大小分布在板层的粘附细胞。我们发现，肌球蛋白簇可以增长与Rho激酶（ROCK）活动单独的肌球蛋白运动活性的情况下。延时成像显示，肌球蛋白簇生长通过增加肌球蛋白协会现有的集群，这是由ROCK依赖性肌球蛋白丝组装增强。启用肌球蛋白运动活性允许通过依赖于F-肌动蛋白结构的肌球蛋白缔合进一步肌球蛋白簇生长。使用一个玩具模型，我们表明，肌球蛋白的自亲和性是足够的概括实验观察到的肌球蛋白簇的大小分布，和肌球蛋白簇的大小是由池的肌球蛋白可用于集群的增长。总之，我们的研究结果提供了新的见解肌球蛋白簇的大小在板层肌动球蛋白细胞骨架的调节。
The actomyosin cytoskeleton generates mechanical forces that power important cellular processes, such as cell migration, cell division, and mechanosensing. Actomyosin self-assembles into contractile networks and bundles that underlie force generation and transmission in cells. A central step is the assembly of the myosin II filament from myosin monomers, regulation of which has been extensively studied. However, myosin filaments are almost always found as clusters within the cell cortex. While recent studies characterized cluster nucleation dynamics at the cell periphery, how myosin clusters grow on stress fibers remains poorly characterized. Here, we utilize a U2OS osteosarcoma cell line with endogenously tagged myosin II to measure the myosin cluster size distribution in the lamella of adherent cells. We find that myosin clusters can grow with Rho-kinase (ROCK) activity alone in the absence of myosin motor activity. Time-lapse imaging reveals that myosin clusters grow via increased myosin association to existing clusters, which is potentiated by ROCK-dependent myosin filament assembly. Enabling myosin motor activity allows further myosin cluster growth through myosin association that is dependent on F-actin architecture. Using a toy model, we show that myosin self-affinity is sufficient to recapitulate the experimentally observed myosin cluster size distribution, and that myosin cluster sizes are determined by the pool of myosin available for cluster growth. Together, our findings provide new insights into the regulation of myosin cluster sizes within the lamellar actomyosin cytoskeleton.