CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, People's Republic of China.
College of Mechanical and Electronic Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, People's Republic of China.
J R Soc Interface. 2019 Jul 26;16(156):20190022. doi: 10.1098/rsif.2019.0022. Epub 2019 Jul 24.
Myosin II and spectrin β display mechanosensitive accumulations in invasive protrusions during cell-cell fusion of Drosophila myoblasts. The biochemical inhibition and deactivation of these proteins results in significant fusion defects. Yet, a quantitative understanding of how the protrusion geometry and fusion process are linked to these proteins is still lacking. Here we present a quantitative model to interpret the dependence of the protrusion size and the protrusive force on the mechanical properties and microstructures of the actin cytoskeleton and plasma membrane based on a mean-field theory. We build a quantitative linkage between mechanosensitive accumulation of myosin II and fusion pore formation at the tip of the invasive protrusion through local area dilation. The mechanical feedback loop between myosin II and local deformation suggests that myosin II accumulation possibly reduces the energy barrier and the critical radius of fusion pores. We also analyse the effect of spectrin β on maintaining the proper geometry of the protrusions required for the success of cell-cell fusion.
肌球蛋白 II 和血影蛋白 β 在果蝇成肌细胞的细胞-细胞融合过程中，在入侵突起中表现出机械敏感的积累。这些蛋白质的生化抑制和失活会导致严重的融合缺陷。然而，定量理解突起几何形状和融合过程与这些蛋白质之间的关系仍然缺乏。在这里，我们提出了一个定量模型，基于平均场理论，根据肌动球蛋白细胞骨架和质膜的机械性能和微观结构来解释突起大小和突起力的依赖性。我们通过局部区域扩张，建立了肌球蛋白 II 的机械敏感积累与入侵突起尖端融合孔形成之间的定量联系。肌球蛋白 II 和局部变形之间的机械反馈循环表明，肌球蛋白 II 的积累可能降低了融合孔的能量势垒和临界半径。我们还分析了血影蛋白 β 对维持细胞-细胞融合成功所需的突起适当几何形状的影响。
