Body-wide synchronization of insulin-signaling dependent DAF-16/FOXO nuclear translocation pulses correlated with C. elegans growth

Insulin signaling is the core pathway regulating body growth, but the dynamics of insulin signaling across an organism has not been studied experimentally. By imaging C. elegans larvae in microchambers, we follow the key insulin signaling step, DAF-16/FOXO nuclear translocation, at cellular level throughout the body. We show that under constant stress, translocation occurs in stochastic pulses, but with each translocation pulse occurring near-simultaneously in all cells. Pulsatile DAF-16/FOXO translocation is correlated with growth, as periods of long or frequent pulses coincide with bouts of growth arrest, and short, infrequent pulses with body growth, while the animal's ability to arrest growth is lost in daf-16/FOXO mutants. Organism-wide coordination of DAF-16/FOXO translocation pulses might thus be important to ensure uniformity of body growth, with potential implications for understanding tissue- and body-wide coordination of insulin-dependent processes also in humans.