Forkhead box protein O3 (FOXO3 (also commonly referred to as FOXO3a))

Forkhead box protein O3 is a member of the forkhead family of transcription factors characterized by a conserved fork head DNA-binding domain. It acts primarily as a transcriptional activator regulating genes involved in apoptosis, autophagy, oxidative resistance, metabolism, immune function, and cellular homeostasis. Its activity is tightly controlled by post-translational modifications—including phosphorylation via the PI3K/Akt pathway—which determine its subcellular localization between nucleus and cytoplasm. Genetic variants in *FOXO3* are strongly associated with human longevity across populations; functional studies implicate it in protection against age-related diseases like cancer and cardiovascular disorders through maintenance of cellular homeostasis under stress conditions.

Other names

FOXO3FOXO3aForkhead box O3FKHRL1 (less common)Forkhead transcription factor O subfamily member 3

Drugs or compounds that modulate upstream kinases/phosphatases can regulate FOXO3 by altering its phosphorylation state, nuclear localization, and transcriptional activity. For example, PI3K/Akt pathway inhibitors can activate FOXO3 by preventing its phosphorylation and nuclear export. Agents affecting oxidative/metabolic stress may indirectly activate or inhibit FOXO3 function.