Prolonged starvation leads to acute stress, inducing a state of cellular dormancy with reduced energy consumption. Our research reveals that nutrient deprivation halts the movement of large ribosomal subunits, trapping them in a gel-like structure within the cytoplasm of surviving cells. This effect is due to water efflux from cells, causing a decrease in cell volume to half the original volume. This simple physical strategy saves, in a dormant state 10⁷ ATP per second, which is needed for normal protein production. We monitored the diffusion of GFP (radius 2.3 nm) and 40S and 60S ribosomes (radii 3.75 and 15 nm, respectively) in the cytoplasm and nucleus during starvation of HeLa cells. GFP and 40S ribosomes slowed their diffusion in the cytoplasm two and five times, respectively. 60S ribosomes exhibited only rotational diffusion. In non-starving cells, biomolecules get stuck in the gel structure of cytoplasm with sizes >100 nm. We show that the gel pore size decreased from 100 nm to 30 nm upon starvation. The diffusive transport in the cell nucleus didn't change during starvation. GFP and ribosomes had the same diffusion coefficients in non-starving and starving cells in the nucleus. This highlights the importance of nuclear transport in cancer cells during extreme stress conditions.

中文翻译：

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饥饿在哺乳动物细胞中诱导纳米级扩散阻碍


长时间的饥饿会导致急性应激，诱导细胞休眠状态，同时降低能量消耗。我们的研究表明，营养匮乏会阻止大核糖体亚基的运动，将它们困在存活细胞的细胞质内的凝胶状结构中。这种效应是由于细胞中的水分流出，导致细胞体积减少到原始体积的一半。这种简单的物理策略在休眠状态下每秒节省 10⁷ 个 ATP，这是正常蛋白质生产所必需的。我们监测了 HeLa 细胞饥饿期间 GFP （半径 2.3 nm） 以及 40S 和 60S 核糖体 （半径分别为 3.75 和 15 nm） 在细胞质和细胞核中的扩散。GFP 和 40S 核糖体分别减慢了它们在细胞质中的扩散 2 倍和 5 倍。60S 核糖体仅表现出旋转扩散。在非饥饿细胞中，生物分子卡在大小为 >100 nm 的细胞质的凝胶结构中。我们表明，饥饿后凝胶孔径从 100 nm 减小到 30 nm。饥饿期间细胞核中的扩散运输没有改变。GFP 和核糖体在细胞核中的非饥饿细胞和饥饿细胞中具有相同的扩散系数。这突出了在极端应激条件下癌细胞核转运的重要性。