Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB3 0WA, United Kingdom.
Proc Natl Acad Sci U S A. 2013 Aug 27;110(35):14132-7. doi: 10.1073/pnas.1302736110. Epub 2013 Aug 12.
Many cells exhibit large-scale active circulation of their entire fluid contents, a process termed cytoplasmic streaming. This phenomenon is particularly prevalent in plant cells, often presenting strikingly regimented flow patterns. The driving mechanism in such cells is known: myosin-coated organelles entrain cytoplasm as they process along actin filament bundles fixed at the periphery. Still unknown, however, is the developmental process that constructs the well-ordered actin configurations required for coherent cell-scale flow. Previous experimental works on streaming regeneration in cells of Characean algae, whose longitudinal flow is perhaps the most regimented of all, hint at an autonomous process of microfilament self-organization driving the formation of streaming patterns during morphogenesis. Working from first principles, we propose a robust model of streaming emergence that combines motor dynamics with both microscopic and macroscopic hydrodynamics to explain how several independent processes, each ineffectual on its own, can reinforce to ultimately develop the patterns of streaming observed in the Characeae and other streaming species.
许多细胞表现出其整个液体内容物的大规模主动循环，这一过程称为细胞质流动。这种现象在植物细胞中尤为普遍，通常呈现出明显规则的流动模式。这种细胞中的驱动机制是已知的：肌球蛋白覆盖的细胞器在沿着固定在周边的肌动蛋白丝束移动时带动细胞质。然而，尚不清楚的是，用于构建用于连贯细胞尺度流动的有序肌动蛋白结构的发育过程。以前对 Characean 藻类细胞中流动再生的实验工作表明，其纵向流动可能是所有流动中最规则的，暗示了微丝自组织的自主过程驱动了形态发生过程中流动模式的形成。从第一性原理出发，我们提出了一个强大的流动出现模型，该模型将马达动力学与微观和宏观流体动力学结合在一起，解释了几个独立的过程，每个过程本身都没有效果，如何通过加强最终发展出在 Characeae 和其他流动物种中观察到的流动模式。
