近日，美国斯坦福大学的Alexander R. Dunn&Christina L. Hueschen及其研究团队取得一项新进展。经过不懈努力，他们发现涌现肌动蛋白流动能够解释不同的滑行运动模式。相关研究成果已于2024年10月8日在国际知名学术期刊《自然—物理学》上发表。
该研究团队提出F-肌动蛋白的流动是通过自组织产生的，并基于弓形虫的几何形态限制，开发了一个关于F-肌动蛋白流动涌现的连续模型。在F-肌动蛋白周转存在的情况下，该模型预测会出现一种稳态模式，其中肌动蛋白的输运主要指向后方。
去除F-肌动蛋白周转后，会导致肌动蛋白斑块在细胞内上下循环，这一现象在研究人员对活体弓形虫寄生虫中药物稳定的肌动蛋白束的实验观察中得到了证实。这些不同的自组织肌动蛋白状态可以解释观察到的滑行模式，说明了在受限几何形态中，F-肌动蛋白流动的自组织特性如何内在地导致不同形式的滑行运动性的出现。
据悉，在宿主感染过程中，弓形虫及相关单细胞寄生虫采用滑行方式移动，这从根本上不同于已知的其他真核细胞运动机制。滑行被认为是由一层薄薄的流动丝状（F）-肌动蛋白层驱动的，该层夹在质膜和覆盖有肌球蛋白的内膜复合物之间。然而，这一表层肌动蛋白层如何驱动实验中观察到的各种滑行模式——螺旋形、圆形、旋转形以及斑块状、钟摆状或滚动状——尚不清楚。
附：英文原文
Title: Emergent actin flows explain distinct modes of gliding motility
Author: Hueschen, Christina L., Segev-Zarko, Li-av, Chen, Jian-Hua, LeGros, Mark A., Larabell, Carolyn A., Boothroyd, John C., Phillips, Rob, Dunn, Alexander R.
Issue&Volume: 2024-10-08
Abstract: During host infection, Toxoplasma gondii and related unicellular parasites move using gliding, which differs fundamentally from other known mechanisms of eukaryotic cell motility. Gliding is thought to be powered by a thin layer of flowing filamentous (F)-actin sandwiched between the plasma membrane and a myosin-covered inner membrane complex. How this surface actin layer drives the various gliding modes observed in experiments—helical, circular, twirling and patch, pendulum or rolling—is unclear. Here we suggest that F-actin flows arise through self-organization and develop a continuum model of emergent F-actin flow within the confines provided by Toxoplasma geometry. In the presence of F-actin turnover, our model predicts the emergence of a steady-state mode in which actin transport is largely directed rearward. Removing F-actin turnover leads to actin patches that recirculate up and down the cell, which we observe experimentally for drug-stabilized actin bundles in live Toxoplasma gondii parasites. These distinct self-organized actin states can account for observed gliding modes, illustrating how different forms of gliding motility can emerge as an intrinsic consequence of the self-organizing properties of F-actin flow in a confined geometry.
DOI: 10.1038/s41567-024-02652-4
Source: https://www.nature.com/articles/s41567-024-02652-4