Laboratory of Molecular Pathology, Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan.
Cell Metab. 2011 Sep 7;14(3):390-402. doi: 10.1016/j.cmet.2011.06.019.
Upon nutrient deprivation, cells are thought to suppress biosynthesis but activate catabolic pathways to provide alternative energy sources and nutrients. However, here we provide evidence that in adult male C. elegans, both biosynthesis and degradation activities, including ribosome biogenesis and turnover, are enhanced during early starvation and appear to depend on the availability of intestinal lipid stores. Upon depletion of the intestinal lipids, further food deprivation results in a significant reduction in metabolic activity in the starved male worms. Our data show that adult C. elegans exhibits a two-phase metabolic response to starvation stress: an initial phase with enhanced metabolic activity that rapidly exhausts the lipid stores, followed by a phase with low metabolic activity, which outlasts the life of fed control worms. DAF-2 insulin/IGF-1 receptor signaling to the RAS pathway is required for the starvation-induced ribosome biogenesis and rapid lipid depletion in the initial phase of starvation.
在营养缺乏的情况下,细胞被认为会抑制生物合成,但会激活分解代谢途径,以提供替代的能量来源和营养物质。然而,在这里我们提供的证据表明,在成年雄性秀丽隐杆线虫中,生物合成和降解活动,包括核糖体的生物发生和周转,在早期饥饿时都会增强,并且似乎依赖于肠道脂质储存的可用性。当肠道脂质耗尽时,进一步的食物剥夺会导致饥饿雄性线虫的代谢活性显著降低。我们的数据表明,成年秀丽隐杆线虫对饥饿应激表现出两阶段的代谢反应:最初阶段代谢活性增强,迅速耗尽脂质储存,然后是代谢活性降低的阶段,该阶段持续时间超过喂食对照线虫的寿命。DAF-2 胰岛素/IGF-1 受体信号通路向 RAS 途径的传递,对于饥饿诱导的核糖体生物发生和初始饥饿阶段的快速脂质耗竭是必需的。