The suprachiasmatic nucleus (SCN) acts as the central clock to coordinate circadian oscillations in mammalian behavior, physiology and gene expression. Despite our knowledge of the circadian transcriptome of the SCN, how it impacts genome-wide protein expression is not well understood. In a collaborative study between Dan Figeys' lab at the OISB and Mary Cheng's lab at the University of Toronto just published in PLoS Genetics, they interrogated the murine SCN proteome across the circadian cycle using SILAC-based quantitative mass spectrometry. Their findings reveal that transcriptional regulation is not the only mechanism winding our SCN clock. Their study underscores the significance of post-transcriptional regulation, the surprising prevalence of ultradian protein expression, and the functional implications on mitochondrial energy metabolism.