Prohibition of nucleolar RNA exosome facilitates starvation adaptation
In response to nutrient scarcity, cells must relocate their limited energy for cellular maintenance at the expense of certain processes. How such a tradeoff is achieved remains largely unknown. RNA surveillance is crucial for guarding the integrity of the transcriptome, whose defects are associated with several human diseases. Unexpectedly, we discover that the nucleolar RNA exosome, a key RNA surveillance machine, is prohibited by starvation. This is not merely the cessation of a non-essential process, but rather a key signal to allocate energy. By rewiring one-carbon metabolism, prohibition of RNA exosome inhibits translation, the most energy-consuming process. Energy is then conserved for fat synthesis to enhance systemic stress resistance and starvation survival. Notably, while benefiting starvation fitness, RNA exosome prohibition impairs the lifespan of well-fed animals, indicating a tradeoff between short-term and long-term fitness. Our findings suggest that nucleolar RNA surveillance can be temporarily sacrificed to facilitate starvation adaptation.