Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
RIKEN Center for Biosystems Dynamics Research, Kanagawa 230-0045, Japan.
Nano Lett. 2024 Feb 14;24(6):1825-1834. doi: 10.1021/acs.nanolett.3c02742. Epub 2024 Jan 31.
Self-assembly of nanoscale actin cytoskeletal proteins into filamentous networks requires organizing actin nucleation areas on the plasma membrane through recruiting actin nucleators and nucleation-promoting factors (NPFs) to the areas. To investigate impacts of the nucleation geometry on actin network assembly, we localized NPF or nucleator on defined micropatterns of laterally mobile lipid bilayers confined in a framework of a polymerized lipid bilayer. We demonstrated that actin network assembly in purified protein mixtures was confined on NPF- or nucleator-localized fluid bilayers. By controlling the shape and size of nucleation areas as well as the density and types of localized NPFs and nucleators, we showed that these parameters regulate actin network architectures. Actin network assembly in egg extracts was also spatially controlled by patterning bilayers containing phosphatidylinositol 4,5-bisphoshate (PI(4,5)P), an essential lipid signaling mediator. Therefore, the system provides a promising platform to investigate the physical and biochemical principles for actin network assembly.
纳米尺度肌动蛋白细胞骨架蛋白的自组装成纤维状网络需要通过将肌动蛋白成核因子和成核促进因子（NPFs）募集到质膜上的成核区域来组织质膜上的肌动蛋白成核区域。为了研究成核几何形状对肌动蛋白网络组装的影响，我们将 NPF 或成核因子定位在受聚合物化脂质双层框架限制的侧向可移动脂质双层的明确定义的微图案上。我们证明，在纯化的蛋白质混合物中，肌动蛋白网络的组装被限制在 NPF 或成核因子定位的流体双层上。通过控制成核区域的形状和大小以及局部 NPF 和成核因子的密度和类型，我们表明这些参数调节肌动蛋白网络结构。含有磷脂酰肌醇 4,5-二磷酸（PI（4,5）P）的双层的图案化也可以在卵提取物中对肌动蛋白网络组装进行空间控制，PI（4,5）P 是一种重要的脂质信号转导介质。因此，该系统为研究肌动蛋白网络组装的物理和生化原理提供了一个有前途的平台。
