The role and implications of mammalian cellular circadian entrainment

The ability to align circadian phase to specific cues, or 'entrainment', is a defining feature of a circadian rhythm. Entrainment is critical for useful circadian function, as it enables organisms to determine the specific time of day to perform temporally restricted behavioural and physiological activities, ranging from sleep to cell division. While mammals have long been known to entrain their circadian rhythm, recent work has shed light on how this is achieved in every single cell, all of which maintain their own individual circadian oscillation. Here I will highlight the current understanding of how the major entraining cues of light, feeding and temperature are communicated to cells to alter their phase. Knowledge of the mechanisms of cellular entrainment has the capacity to impact both fundamental understanding of circadian rhythms and our application of cellular circadian research to real-world problems, including shift work.