Measuring molecular rupture forces between single actin filaments and actin-binding proteins
Measuring molecular rupture forces between single actin filaments and actin-binding proteins
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DOI：
10.1073/pnas.0706124105
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发表时间：
2008-07-08
影响因子：
11.1
通讯作者：
Lang, Matthew J.
中科院分区：
文献类型：
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作者：
Ferrer, Jorge M.;Lee, Hyungsuk;Lang, Matthew J.
肌动蛋白结合蛋白 (ABP) 调节肌动蛋白丝 (F-肌动蛋白) 组装成网络和束，从而保证细胞的结构完整性。其中两种 ABP，细丝蛋白和α-肌动蛋白，已被广泛用于模拟体外生长的肌动蛋白网络的机械特性。然而，对于 ABP 和 F-肌动蛋白之间的分子相互作用如何调节细胞骨架的动态特性还缺乏了解。在这里，我们提出了一种类似天然的测定几何结构来测试由连接两个准平行肌动蛋白丝的 ABP 形成的复合物的断裂力。我们通过使用两种不同的 ABP（细丝蛋白和α-肌动蛋白）进行测试，轻松证明了该测定法的适应性。对于细丝蛋白/肌动蛋白和 α-肌动蛋白/肌动蛋白，我们测量了 40-80 pN 的相似断裂力，加载速率在 4 至 50 pN/s 之间。观察到 ABP 解折叠和构象转变事件，表明两者都很重要，并且可能是肌动蛋白细胞骨架机械特性的时间调节的重要机制。通过这种模块化的单分子测定，可以研究广泛的 ABP/肌动蛋白相互作用，以更好地了解细胞骨架和细胞动力学。
Actin-binding proteins (ABPs) regulate the assembly of actin filaments (F-actin) into networks and bundles that provide the structural integrity of the cell. Two of these ABPs, filamin and a-actinin, have been extensively used to model the mechanical properties of actin networks grown in vitro; however, there is a lack in the understanding of how the molecular interactions between ABPs and F-actin regulate the dynamic properties of the cytoskeleton. Here, we present a native-like assay geometry to test the rupture force of a complex formed by an ABP linking two quasiparallel actin filaments. We readily demonstrate the adaptability of this assay by testing it with two different ABPs: filamin and a-actinin. For filamin/actin and alpha-actinin/actin, we measured similar rupture forces of 40-80 pN for loading rates between 4 and 50 pN/s. Both ABP unfolding and conformational transition events were observed, demonstrating that both are important and may be a significant mechanism for the temporal regulation of the mechanical properties of the actin cytoskeleton. With this modular, single -molecule assay, a wide range of ABP/actin interactions can be studied to better understand cytoskeletal and cell dynamics.