Large cells often rely on cytoplasmic flows for intracellular transport, maintaining homeostasis, and positioning cellular components. Understanding the mechanisms of these flows is essential for gaining insights into cell function, developmental processes, and evolutionary adaptability. Here, we focus on a class of self-organized cytoplasmic stirring mechanisms that result from fluid–structure interactions between cytoskeletal elements at the cell cortex. Drawing inspiration from streaming flows in late-stage fruit fly oocytes, we propose an analytically tractable active carpet theory. This model deciphers the origins and three-dimensional spatiotemporal organization of such flows. Through a combination of simulations and weakly nonlinear theory, we establish the pathway of the streaming flow to its global attractor: a cell-spanning vortical twister. Our study reveals the inherent symmetries of this emergent flow, its low-dimensional structure, and illustrates how complex fluid–structure interaction aligns with classical solutions in Stokes flow. This framework can be easily adapted to elucidate a broad spectrum of self-organized, cortex-driven intracellular flows.

中文翻译：

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活性地毯的细胞质搅拌


大细胞通常依靠细胞质流进行细胞内运输、维持体内平衡和定位细胞成分。了解这些流动的机制对于深入了解细胞功能、发育过程和进化适应性至关重要。在这里，我们重点研究一类自组织的细胞质搅拌机制，这些机制是由细胞皮层细胞骨架元素之间的流体-结构相互作用产生的。从晚期果蝇卵母细胞的流动中汲取灵感，我们提出了一种易于分析的活性地毯理论。该模型破译了此类流动的起源和三维时空组织。通过模拟和弱非线性理论的结合，我们建立了流向其全局吸引子的路径：跨单元的涡旋扭曲器。我们的研究揭示了这种涌现流的固有对称性及其低维结构，并说明了复杂的流固相互作用如何与斯托克斯流的经典解决方案相一致。该框架可以很容易地适应阐明广泛的自组织、皮层驱动的细胞内流动。