NanoScience Technology Center, University of Central Florida, Orlando, FL, USA.
Department of Materials Science and Engineering, University of Central Florida, Orlando, FL, USA.
FEBS Lett. 2021 Jan;595(1):26-40. doi: 10.1002/1873-3468.13949. Epub 2020 Oct 21.
Fascin and α-actinin form higher-ordered actin bundles that mediate numerous cellular processes including cell morphogenesis and movement. While it is understood crosslinked bundle formation occurs in crowded cytoplasm, how crowding affects the bundling activities of the two crosslinking proteins is not known. Here, we demonstrate how solution crowding modulates the organization and mechanical properties of fascin- and α-actinin-induced bundles, utilizing total internal reflection fluorescence and atomic force microscopy imaging. Molecular dynamics simulations support the inference that crowding reduces binding interaction between actin filaments and fascin or the calponin homology 1 domain of α-actinin evidenced by interaction energy and hydrogen bonding analysis. Based on our findings, we suggest a mechanism of crosslinked actin bundle assembly and mechanics in crowded intracellular environments.
Fascin 和 α-actinin 形成高级别的肌动蛋白束，介导包括细胞形态发生和运动在内的多种细胞过程。虽然交联束的形成发生在拥挤的细胞质中，但拥挤如何影响这两种交联蛋白的成束活性尚不清楚。在这里，我们利用全内反射荧光和原子力显微镜成像技术，展示了溶液拥挤如何调节 fascin 和 α-actinin 诱导的束的组织和力学特性。分子动力学模拟支持这样的推断，即拥挤减少了肌动蛋白丝与 fascin 或 α-actinin 的 calponin 同源 1 结构域之间的结合相互作用，这可以通过相互作用能和氢键分析来证明。基于我们的发现，我们提出了一种在拥挤的细胞内环境中交联肌动蛋白束组装和力学的机制。
