AKT keeps the beat in CLOCK's circadian rhythm.

The circadian clock plays a critical role in physiology and medicine by cyclically regulating the expression of numerous genes. The core components of the clock are thought to be controlled by several regulatory mechanisms, including post-translational modifications, but the full extent of this regulation is not known. In this issue, Sessa and co-workers demonstrate that the transcription factor CLOCK is a direct substrate of the kinase AKT. This phosphorylation controls the nuclear-cytosolic translocation of CLOCK and thus its ability to regulate circadian gene expression in peripheral tissues.