Cell-to-cell variability in AMPK activation reveals autonomous cycles in cellular energy balance

Cellular metabolism can be reconfigured to balance nutrient processing (catabolism) and cellular demands (anabolism). However, the kinetics of reconfiguration within individual mammalian cells, and heterogeneity between cells, have remained unexplored. Using live-cell imaging, we investigate the kinetics of bioenergetic adaptation in individual cells. In response to acute inhibition of oxidative phosphorylation, AMPK substrates are phosphorylated bimodally, identifying cells in different underlying states of anabolism and catabolism. Manipulation of glycolysis, insulin/Akt signaling, or protein synthesis shifts the distribution of these states. Long-term lineage analysis confirms that this cellular energy balance cycles over time within individual cells, independently of the cell division cycle. We further demonstrate that AMPK inhibits the ERK and mTOR cell growth signaling pathways specifically when anabolism is in excess. Our results reveal dynamic fluctuations of energetic balance, establish distinct time scales of cellular energetic control, and open opportunities for more precise prediction and control of cellular metabolic functions.