Center of Bioinformatics, Simulation and Modeling (CBSM), Faculty of Engineering, Universidad de Talca, Talca CL-3460000, Chile.
Plant Physiol. 2021 Dec 4;187(4):2246-2261. doi: 10.1093/plphys/kiab217.
Homeostasis in living cells refers to the steady state of internal, physical, and chemical conditions. It is sustained by self-regulation of the dynamic cellular system. To gain insight into the homeostatic mechanisms that maintain cytosolic nutrient concentrations in plant cells within a homeostatic range, we performed computational cell biology experiments. We mathematically modeled membrane transporter systems and simulated their dynamics. Detailed analyses of 'what-if' scenarios demonstrated that a single transporter type for a nutrient, irrespective of whether it is a channel or a cotransporter, is not sufficient to calibrate a desired cytosolic concentration. A cell cannot flexibly react to different external conditions. Rather, at least two different transporter types for the same nutrient, which are energized differently, are required. The gain of flexibility in adjusting a cytosolic concentration was accompanied by the establishment of energy-consuming cycles at the membrane, suggesting that these putatively "futile" cycles are not as futile as they appear. Accounting for the complex interplay of transporter networks at the cellular level may help design strategies for increasing nutrient use efficiency of crop plants.
活细胞中的稳态是指内部物理和化学条件的稳定状态。它是通过动态细胞系统的自我调节来维持的。为了深入了解维持植物细胞胞质营养浓度在稳态范围内的稳态机制，我们进行了计算细胞生物学实验。我们对膜转运体系统进行了数学建模，并模拟了它们的动力学。对“如果......会怎样”情景的详细分析表明，对于一种营养物质，无论它是通道还是共转运体，单一的转运体类型都不足以校准所需的胞质浓度。细胞不能灵活地对不同的外部条件做出反应。相反，至少需要两种不同的、能量供应方式不同的同种营养物质的转运体类型。在调整胞质浓度方面的灵活性的获得伴随着在膜上建立能量消耗循环，这表明这些推测的“无效”循环并不像它们看起来那样无效。在细胞水平上考虑转运体网络的复杂相互作用可能有助于设计提高作物植物养分利用效率的策略。
