Continuous variable response, kinetic gating and connectivity that govern IS topology are perturbed in hyperinsulinemia

Abstract

Understanding kinetic control of biological processes is as important as identifying components that constitute pathways. Insulin-signaling (IS) is central for almost all metazoans and its perturbations are associated with various diseases and aging. While temporal phosphorylation changes and kinetic constants have provided some insights, constant or variable parameters that establish and maintain signal topology are poorly understood. Our iterative experimental and mathematical simulation-based approaches reveal novel kinetic parameters that encode concentration and nutrient dependent information. Further, we find that pulsatile fasting insulin rewires IS akin to memory and in anticipation of a fed response. Importantly, selective kinetic gating of signals and maximum connectivity, between metabolic and growth-factor arms under normo-insulinemic states, maintains network topology. In addition to unraveling kinetic constraints that determine cascade architecture, our findings will help in identifying novel therapeutic strategies that conserve coupling between metabolic and growth-factor arms, which is lost in diseases and conditions of hyperinsulinemia.