Insulin/IGF-1 pathway

The insulin/IGF-1 pathway (often abbreviated IIS) is a conserved nutrient-sensing network in which insulin and IGF-1 bind tyrosine kinase receptors to activate PI3K, AKT, and mTOR while inhibiting FOXO. It coordinates glucose uptake, growth, and anabolic metabolism with nutrient availability. Loss-of-function mutations along this pathway dramatically extend lifespan in C. elegans (daf-2), Drosophila, and mice, establishing IIS as a foundational longevity pathway across the animal kingdom.