Balcioglu Hayri E, Harkes Rolf, Danen Erik H J, Schmidt Thomas
Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands.
Physics of Life Processes, Kamerlingh Onnes-Huygens Laboratory, Leiden University, Leiden, The Netherlands.
J Chem Phys. 2022 Feb 28;156(8):085101. doi: 10.1063/5.0077004.
In cell-matrix adhesions, integrin receptors and associated proteins provide a dynamic coupling of the extracellular matrix (ECM) to the cytoskeleton. This allows bidirectional transmission of forces between the ECM and the cytoskeleton, which tunes intracellular signaling cascades that control survival, proliferation, differentiation, and motility. The quantitative relationships between recruitment of distinct cell-matrix adhesion proteins and local cellular traction forces are not known. Here, we applied quantitative super-resolution microscopy to cell-matrix adhesions formed on fibronectin-stamped elastomeric pillars and developed an approach to relate the number of talin, vinculin, paxillin, and focal adhesion kinase (FAK) molecules to the local cellular traction force. We find that FAK recruitment does not show an association with traction-force application, whereas a ∼60 pN force increase is associated with the recruitment of one talin, two vinculin, and two paxillin molecules on a substrate with an effective stiffness of 47 kPa. On a substrate with a fourfold lower effective stiffness, the stoichiometry of talin:vinculin:paxillin changes to 2:12:6 for the same ∼60 pN traction force. The relative change in force-related vinculin recruitment indicates a stiffness-dependent switch in vinculin function in cell-matrix adhesions. Our results reveal a substrate-stiffness-dependent modulation of the relationship between cellular traction-force and the molecular stoichiometry of cell-matrix adhesions.
在细胞-基质黏附中，整合素受体及相关蛋白实现了细胞外基质（ECM）与细胞骨架的动态偶联。这使得ECM与细胞骨架之间能够进行双向力传递，进而调节控制细胞存活、增殖、分化和迁移的细胞内信号级联反应。不同细胞-基质黏附蛋白的募集与局部细胞牵引力之间的定量关系尚不清楚。在此，我们将定量超分辨率显微镜应用于在纤连蛋白印记弹性柱上形成的细胞-基质黏附，并开发了一种方法来关联桩蛋白、纽蛋白、桩蛋白和粘着斑激酶（FAK）分子的数量与局部细胞牵引力。我们发现，FAK的募集与牵引力的施加并无关联，而在有效刚度为47 kPa的基质上，约60 pN的力增加与一个桩蛋白、两个纽蛋白和两个桩蛋白分子的募集相关。在有效刚度低四倍的基质上，对于相同的约60 pN牵引力，桩蛋白:纽蛋白:桩蛋白的化学计量比变为2:12:6。与力相关的纽蛋白募集的相对变化表明细胞-基质黏附中纽蛋白功能存在刚度依赖性转变。我们的结果揭示了细胞牵引力与细胞-基质黏附分子化学计量比之间关系的底物刚度依赖性调节。
