PERsuading nuclear receptors to dance the circadian rhythm.

The recurring light/dark cycle that has a period length of about 24 hours has been internalized in various organisms in the form of a circadian clock. This clock allows a precise orchestration of biochemical and physiological processes in the body thus improving performance. Recently, we found that the clock component PERIOD2 (PER2) can coordinate transcriptional regulation of metabolic, physiological, or behavioral pathways by interacting with nuclear receptors. PER2 appears to act as co-regulator of nuclear receptors linking clock function and transcriptional regulation at the level of protein-protein interactions. Here, we provide additional evidence for modulation of nuclear receptor dependent transcription by PER2 underscoring the broad implication of our finding. Taken together, our findings provide a base for the understanding of various disorders including mood disorders that have their roots in a temporal deregulation of basic metabolic processes.