Giant fluctuations and structural effects in a flocking epithelium
Giant fluctuations and structural effects in a flocking epithelium
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DOI：
10.1088/1361-6463/aa7f8e
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发表时间：
2017-09-27
影响因子：
3.4
通讯作者：
Cerbino, Roberto
中科院分区：
文献类型：
--
作者：
Giavazzi, Fabio;Malinverno, Chiara;Cerbino, Roberto
培养在单层中的上皮细胞在隔离时非常能动，但当有丝分裂增加其数量超过临界阈值时，就会达到近乎拥挤的状态。我们最近已经证明，单分子层可以通过过度表达单一蛋白RAB5A来重新唤醒，RAB5A是内吞作用的主要调节因子。这种能动性的重新觉醒被解释为促进了大规模集体移徙模式的出现的蜂拥而至的过渡。在这里，我们关注的是这种重新觉醒对单层结构性质的影响。我们发现，无堵塞的单分子膜的特征是在单胞水平上的流态化，以及在较大长度尺度上增强的非平衡大尺度数涨落。此外，借助数值模拟，我们将这些涨落的起源追溯到组分的自发活动性质，以及局部排列机制的存在，从而导致取向对称性的自发破缺。
Epithelial cells cultured in a monolayer are very motile in isolation but reach a near-jammed state when mitotic division increases their number above a critical threshold. We have recently shown that a monolayer can be reawakened by over-expression of a single protein, RAB5A, a master regulator of endocytosis. This reawakening of motility was explained in terms of a flocking transition that promotes the emergence of a large-scale collective migratory pattern. Here we focus on the impact of this reawakening on the structural properties of the monolayer. We find that the unjammed monolayer is characterised by a fluidisation at the single cell level, and by enhanced non-equilibrium large-scale number fluctuations at a larger length scale. Also, with the help of numerical simulations, we trace back the origin of these fluctuations to the self-propelled active nature of the constituents, and to the existence of a local alignment mechanism, leading to the spontaneous breaking of the orientational symmetry.