细胞控制黏度以应对温度和能量供应的变化。
Cellular Control of Viscosity Counters Changes in Temperature and Energy Availability.
机构信息
Department of Biology, Stanford University, Stanford, CA 94305, USA.
Department of Biology, Stanford University, Stanford, CA 94305, USA; Department of Biochemistry, Stanford University, Stanford, CA 94305, USA.
出版信息
Cell. 2020 Dec 10;183(6):1572-1585.e16. doi: 10.1016/j.cell.2020.10.017. Epub 2020 Nov 5.
Cellular functioning requires the orchestration of thousands of molecular interactions in time and space. Yet most molecules in a cell move by diffusion, which is sensitive to external factors like temperature. How cells sustain complex, diffusion-based systems across wide temperature ranges is unknown. Here, we uncover a mechanism by which budding yeast modulate viscosity in response to temperature and energy availability. This "viscoadaptation" uses regulated synthesis of glycogen and trehalose to vary the viscosity of the cytosol. Viscoadaptation functions as a stress response and a homeostatic mechanism, allowing cells to maintain invariant diffusion across a 20°C temperature range. Perturbations to viscoadaptation affect solubility and phase separation, suggesting that viscoadaptation may have implications for multiple biophysical processes in the cell. Conditions that lower ATP trigger viscoadaptation, linking energy availability to rate regulation of diffusion-controlled processes. Viscoadaptation reveals viscosity to be a tunable property for regulating diffusion-controlled processes in a changing environment.
细胞功能的实现需要在时间和空间上协调数以千计的分子相互作用。然而，细胞中的大多数分子都是通过扩散来运动的，而扩散容易受到温度等外部因素的影响。细胞如何在较宽的温度范围内维持复杂的基于扩散的系统尚不清楚。在这里，我们揭示了出芽酵母响应温度和能量可用性来调节粘度的机制。这种“粘弹性适应”利用糖原和海藻糖的调节合成来改变细胞质的粘度。粘弹性适应作为一种应激反应和一种动态平衡机制，使细胞能够在 20°C 的温度范围内保持不变的扩散。对粘弹性适应的干扰会影响溶解度和相分离，表明粘弹性适应可能对细胞中的多种生物物理过程有影响。降低 ATP 的条件会触发粘弹性适应，将能量可用性与扩散控制过程的速率调节联系起来。粘弹性适应揭示了粘度是在不断变化的环境中调节扩散控制过程的可调特性。
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