Sestrin protein. Molecular model of sestrin 2 (SESN2) in complex with 4-(difluoromethyl)-L-leucine. Sestrins are stress-responsive genes whose expression is triggered under conditions of stress, such as hypoxia, DNA damage, starvation, radiation, and oxidative stress. Sestrins function as antioxidants and are mediators of exercise benefits. Here, the protein domains are colour-coded: Sens-A (pink), Sens-B (pale pink), Sens-C (blue).