Circadian Clocks and Cell Physiology: Circle of Life



Dr. Andrew Liu; Associate Professor, University of Memphis

September 15 in the Fralin Auditorium, Fralin Hall 102

Hosted by Dr. Shihoko Kojima



Virtually every cell in the body has a ~24-hr clock. So, as we go about living our lives, hundreds of billions of clock cells are ticking within us, culminating in circadian rhythms in behavior and physiology. The hallmark of circadian timekeeping is cyclic gene expression. Towards a systems level understanding of circadian timekeeping, genomic studies have uncovered hundreds to thousands of rhythmically expressed genes, regulated by the clock. However, the converse regulation has been less understood. By leveraging cell-based clock models and functional genomic approaches, we identified hundreds of genes that modify the clock. These genes function in various cellular pathways, including metabolism, cell cycle control, and stress responses such as inflammation and heat shock. These findings contribute to an emerging view that, while the clock regulates physiology, physiological homeostasis can have important impacts on the circadian clock. It is likely that most, if not all, major cellular networks are integrated with the circadian clock—a complex system, indeed! I will discuss a few examples of this crosstalk between the circadian clock and cell physiology at the biochemical, molecular and physiological levels. These findings are expected to have important implications in physiology and medicine.

Liu et al, Cell, 2007 “ Intercellular coupling confers robustness against mutations in the SCN circadian clock network”.

Zhang et al, Cell, 2009 “A Genome-wide siRNA screen for modifiers of the circadian clock in human cells".

Ramanathan et al, PLoS Genet, 2014 “Cell type-specific functions of Period genes revealed by novel adipocyte and hepatocyte circadian clock models”.

This seminar will NOT be livestreamed.

liu flyer