Abstract
Temporal organization of nutrient and energy metabolism is important for maintaining homeostasis in mammals. Autophagy is a conserved cellular pathway that is activated in response to nutrient limitation, resulting in the degradation of cytoplasmic components and the release of amino acids and other nutrients. Recently, we reported that autophagy exhibits robust circadian rhythm in mouse liver, accompanied by cyclic induction of genes involved in various steps of autophagy. Rhythmic activation of physiological autophagy appears to be regulated by transcription factor C/EBPβ, which is sufficient and required for nutritional and circadian regulation of autophagy gene expression. These findings provide new insight into transcriptional control of autophagy and reveal a potentially important role of autophagy cycles in metabolic homeostasis.