Investigating subcellular localization of tPA and PAI-1 in the mammalian circadian clock

suprachiasmatic nucleus (SCN) of the hypothalamus is the circadian rhythm’s master pacemaker. The SCN functions to continuously maintain the 24-hour cadence of the internal circadian clock and can adapt to external light stimuli in order to synchronize the animal’s circadian rhythm to the environment. Light is a Zeitgeber, German for “time-giver,” that mediates entrainment by inducing shifts in the clock phase. Notably, phase shifts only occur at night, but the mechanisms gating phase shifting remain poorly understood.