The circadian clock is an internal timekeeping system that plays an important role in an organism’s physiology. Its dysfunction contributes to the development of many diseases. Recent data suggest that core clock proteins, which are crucial for proper operation of the circadian oscillator, also have essential noncircadian functions important for normal tissue homeostasis (eg, deficiency in the circadian proteins BMAL1, PER2, and CLOCK results in accelerated aging syndrome in mice). Hence, disruption of the circadian system will not only lead to desynchronization of various metabolic processes, but will also interfere with other physiological functions of core clock proteins (such as control of reactive oxygen species homeostasis, cellular senescence, and genotoxic stress response), thus contributing to the acceleration of aging...