Circadian clock

The circadian clock is an endogenous oscillator that drives daily rhythms in physiology and behavior. The mechanism underlying circadian timekeeping is cell-autonomous and oscillations are generated by interconnecting transcriptional and translational feedback loops. To date large-scale approaches to study molecular circadian rhythms have been limited to the analysis of the transcriptome (mRNA). However, the “true” mediators of cellular functions are proteins. Recent advances in mass spectrometric and bioinformatics technology now allow global quantitation of protein abundance and phosphorylation. The aim of our work is to apply the latest methodology in mass spectrometry and bioinformatics, in combination with stable isotope labeling by amino acids in cell culture (SILAC), or in mice, to the investigation of circadian clocks in mammals. We are performing comprehensive quantitative analysis of protein and phosphoprotein in circadian oscillations in mouse tissues.