Department of Finemechanics, Tohoku University, Sendai, Miyagi, Japan.
Department of Finemechanics, Tohoku University, Sendai, Miyagi, Japan.
Biophys J. 2019 Apr 23;116(8):1483-1494. doi: 10.1016/j.bpj.2019.03.017. Epub 2019 Mar 28.
Biomembranes feature phospholipid bilayers and serve as the interface between cells or organelles and the extracellular and/or cellular environment. Lipids can move freely throughout the membrane; the lipid bilayer behaves like a fluid. Such fluidity is important in terms of the actions of membrane transport proteins, which often mediate biological functions; membrane protein motion has attracted a great deal of attention. Because the proteins are small, diffusion phenomena are often in play, but flow-induced transport has rarely been addressed. Here, we used a dissipative particle dynamics approach to investigate flow-induced membrane protein transport. We analyzed the drift of a membrane protein located within a vesicle. Under the influence of shear flow, the protein gradually migrated toward the vorticity axis via a random walk, and the probability of retention around the axis was high. To understand the mechanism of protein migration, we varied both shear strength and protein size. Protein migration was induced by the balance between the drag and thermodynamic diffusion forces and could be represented by the Péclet number. These results improve our understanding of flow-induced membrane protein transport.
生物膜的特征是磷脂双层，并作为细胞或细胞器与细胞外和/或细胞环境之间的界面。脂质可以在整个膜中自由移动；脂质双层的行为类似于流体。这种流动性对于膜转运蛋白的作用非常重要，因为膜转运蛋白经常介导生物功能；膜蛋白的运动引起了广泛关注。由于蛋白质较小，扩散现象经常起作用，但很少涉及流致输运。在这里，我们使用耗散粒子动力学方法研究了流致膜蛋白输运。我们分析了位于囊泡内的膜蛋白的漂移。在切向流的影响下，蛋白质通过随机游动逐渐向涡度轴迁移，并且在轴周围保留的概率很高。为了了解蛋白质迁移的机制，我们改变了切变强度和蛋白质大小。蛋白质迁移是由阻力和热力学扩散力之间的平衡引起的，可以用 Peclet 数来表示。这些结果提高了我们对流致膜蛋白输运的理解。
