The Karpac Lab is broadly interested in the origins of signaling networks that provide animals with metabolic flexibility, and thus the capacity to balance energy homeostasis. These ancient networks, under intense evolutionary pressure, both respond to and are shaped by diverse inputs, such as nutrient availability, pathogens, and aging. We primarily use the fruit fly Drosophila melanogaster as a genetic model to investigate the function and integration of these signaling networks at multiple levels of biological organization: from molecules, to cells and tissues, to inter-organ communication, to organismal physiology and aging.