Department of Biology, Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Straße 23, D-67663 Kaiserslautern, Germany.
Biol Chem. 2019 Jun 26;400(7):879-893. doi: 10.1515/hsz-2018-0436.
Cells are highly adaptive systems that respond and adapt to changing environmental conditions such as temperature fluctuations or altered nutrient availability. Such acclimation processes involve reprogramming of the cellular gene expression profile, tuning of protein synthesis, remodeling of metabolic pathways and morphological changes of the cell shape. Nutrient starvation can lead to limited energy supply and consequently, remodeling of protein synthesis is one of the key steps of regulation since the translation of the genetic code into functional polypeptides may consume up to 40% of a cell's energy during proliferation. In eukaryotic cells, downregulation of protein synthesis during stress is mainly mediated by modification of the translation initiation factors. Prokaryotic cells suppress protein synthesis by the active formation of dimeric so-called 'hibernating' 100S ribosome complexes. Such a transition involves a number of proteins which are found in various forms in prokaryotes but also in chloroplasts of plants. Here, we review the current understanding of these hibernation factors and elaborate conserved principles which are shared between species.
细胞是高度适应性的系统，能够响应和适应环境条件的变化，如温度波动或营养可用性的改变。这种适应过程涉及细胞基因表达谱的重新编程、蛋白质合成的调整、代谢途径的重塑以及细胞形状的形态变化。营养饥饿会导致能量供应有限，因此，蛋白质合成的重塑是调节的关键步骤之一，因为遗传密码翻译成功能多肽可能在细胞增殖过程中消耗多达 40%的能量。在真核细胞中，应激过程中蛋白质合成的下调主要是通过翻译起始因子的修饰来介导的。原核细胞通过形成活性二聚体所谓的“休眠”100S 核糖体复合物来抑制蛋白质合成。这种转变涉及许多蛋白质，这些蛋白质在原核生物中以不同的形式存在，但也存在于植物的叶绿体中。在这里，我们回顾了对这些休眠因子的现有理解，并详细阐述了物种间共享的保守原则。
