Nutrient availability and growth: regulation of insulin signaling by dFOXO/FOXO1.

Organisms adjust their rate of growth depending on the availability of nutrients. Thus, when environmental conditions limit nutrients, growth is slowed and is only restored after food again becomes abundant. Many aspects of the molecular mechanisms that govern this complex control system remain unknown. However, it has been shown that the insulin/IGF-1 (insulin-like growth factor 1) receptor pathway, together with the FOXO family of transcription factors, play an important role in this process. Recent studies with the fruit fly Drosophila melanogaster have provided new insights into the regulatory circuitry that controls both growth and gene expression in response to nutrient availability.