FoxO transcription factors in oxidative stress response and ageing--a new fork on the way to longevity?

Forkhead box O (FoxO) transcription factors are important downstream targets of the PI3K/Akt signaling pathway and crucial regulators of cell fate. This function of FoxOs relies on their ability to control diverse cellular functions, including proliferation, differentiation, apoptosis, DNA repair, defense against oxidative stress and ageing. FoxOs are regulated by a variety of different growth factors and hormones, and their activity is tightly controlled by post-translational modifications, including phosphorylation, acetylation, ubiquitination and interaction with different proteins and transcription factors. This brief review focuses on the molecular mechanisms, cellular effects and resulting organismal phenotypes generated by differentially regulated FoxO proteins and discusses our current understanding of the role of FoxOs in disease and ageing processes.