自发运动是大多数后生动物细胞的共同特征，通常归因于肌动球蛋白网络的特性。这种产生力的机制已经被研究到最微小的分子细节，特别是在片状足驱动的迁移中。然而，肌动球蛋白网络如何在收缩驱动的变形细胞内工作仍然缺乏统一的原则。在这里，我们使用 HeLa 细胞的稳定运动泡作为变形虫运动系统模型，在单丝水平上对肌动蛋白皮层的动力学进行成像，并揭示了三个不同流变阶段的共存。我们引入了“平流渗透”，这是刚性渗透和主动平流协同作用的过程，在空间上将肌动蛋白网络的机械特性组织成最小且通用的运动机制。根据我们对简化系统的观察，我们推测该模型可以在单肌动蛋白丝水平上解释变形虫细胞（例如癌细胞或免疫细胞）如何有效地穿过复杂的 3D 环境。版权所有 © 2024 Elsevier Inc.保留权利。

Spontaneous locomotion is a common feature of most metazoan cells, generally attributed to the properties of actomyosin networks. This force-producing machinery has been studied down to the most minute molecular details, especially in lamellipodium-driven migration. Nevertheless, how actomyosin networks work inside contraction-driven amoeboid cells still lacks unifying principles. Here, using stable motile blebs from HeLa cells as a model amoeboid motile system, we imaged the dynamics of the actin cortex at the single filament level and revealed the co-existence of three distinct rheological phases. We introduce "advected percolation," a process where rigidity percolation and active advection synergize, spatially organizing the actin network's mechanical properties into a minimal and generic locomotion mechanism. Expanding from our observations on simplified systems, we speculate that this model could explain, down to the single actin filament level, how amoeboid cells, such as cancer or immune cells, can propel efficiently through complex 3D environments.Copyright © 2024 Elsevier Inc. All rights reserved.