How chemical processes control the mammal's internal daily clock

The circadian clock is driven by transcription-translation feedback loops involving core proteins such as CLOCK, BMAL1, PER, and CRY.

• Circadian rhythms synchronize physiological functions with daily environmental changes across various organisms.
• Disruption of the circadian clock is linked to multiple human diseases, including sleep disorders, metabolic syndrome, and potentially cancer.
• CLOCK and BMAL1 act as activators, while PER and CRY function as repressors in the regulation of the circadian clock.
• The CRY-PER-CK1 complex binds to CLOCK-BMAL1 during the early repression phase, inhibiting its activity.
• In the late repression phase, CRY1 alone can suppress CLOCK-BMAL1 by preventing the recruitment of coactivators.
• Protein-protein interactions, protein-DNA interactions, and posttranslational modifications are crucial for the regulation of the molecular clock.

Simplified