近日，美国耶鲁大学Murrell, Michael P.研究组近日取得一项新成果。经过不懈努力，他们对细胞皮层的能量分配进行了研究。相关研究成果已于2024年9月12日在国际知名学术期刊《自然—物理学》上发表。
该研究团队测量了细胞皮质中化学和机械子系统在不同模式驱动下远离平衡态时的熵产生率。研究人员通过操控控制皮质肌动蛋白纤维和肌球蛋白-II的Rho GTP酶途径来实现这一点。在GTP酶激活蛋白表达水平较低时，会产生脉冲或断续的Rho和肌动蛋白纤维波，此时能量在两个子系统之间按比例分配，并受到昂萨格互易性的约束。
在互易性范围内，断续波中的熵产生率达到最大。当皮质被驱动成迷宫状或螺旋状行波时，互易性被打破，标志着能量分配的差异逐渐增大，以及化学和机械活动的解耦。
研究人员进一步证明，能量分配和互易性由化学反应和机械松弛之间的竞争时间尺度决定。
据悉，生命系统通过不断消耗环境能量而远离热力学平衡状态。在细胞皮质中，这种能量被投入到化学和机械活动中各种模式的形成中，这些活动的空间和时间动态决定了细胞的表型和行为。然而，细胞如何在这些活动之间分配内部能量尚不清楚。
附：英文原文
Title: Energy partitioning in the cell cortex
Author: Chen, Sheng, Seara, Daniel S., Michaud, Ani, Kim, Songeun, Bement, William M., Murrell, Michael P.
Issue&Volume: 2024-09-12
Abstract: Living systems are driven far from thermodynamic equilibrium through the continuous consumption of ambient energy. In the cell cortex, this energy is invested in the formation of diverse patterns in chemical and mechanical activities, whose spatial and temporal dynamics determine the cell phenotypes and behaviours. How cells partition internal energy between these activities is unknown. Here we measured the entropy production rate of both chemical and mechanical subsystems of the cell cortex across a variety of patterns as the system is driven further from equilibrium. We do this by manipulating the Rho GTPase pathway, which controls the cortical actin filaments and myosin-II. At lower levels of GTPase-activating protein expression, which produce pulses or choppy Rho and actin filament waves, energy is proportionally partitioned between the two subsystems and is subject to the constraint of Onsager reciprocity. Within the range of reciprocity, the entropy production rate is maximized in choppy waves. As the cortex is driven into labyrinthine or spiral travelling waves, reciprocity is broken, marking an increasingly differential partitioning of energy and an uncoupling of chemical and mechanical activities. We further demonstrate that energy partitioning and reciprocity are determined by the competing timescales between chemical reaction and mechanical relaxation.
DOI: 10.1038/s41567-024-02626-6
Source: https://www.nature.com/articles/s41567-024-02626-6