Period circadian protein homolog 1

Period circadian protein homolog 1 (PER1) is a protein that in humans is encoded by the PER1 gene. It is a core component of the circadian clock, the internal system that regulates the roughly 24-hour cycle of biological processes in animals, plants, and fungi.

Function

The PER1 protein is a member of the Period family of proteins, which play a central role in the maintenance of circadian rhythms. It interacts with other circadian clock proteins, including Cryptochrome and CLOCK, to regulate the timing of circadian rhythms.

PER1 is primarily expressed in the suprachiasmatic nucleus (SCN), the body's central circadian clock, but it is also found in other tissues, including the liver and kidney. The protein is involved in the negative feedback loop that maintains the circadian rhythm: it inhibits the activity of the CLOCK: BMAL1 complex, reducing the transcription of its own gene and resetting the clock.

Clinical significance

Alterations in the PER1 gene or its protein product have been associated with a number of health conditions. For example, mutations in PER1 can lead to Familial advanced sleep phase syndrome, a condition characterized by significantly advanced sleep onset and offset times.

In addition, there is evidence that PER1 may play a role in cancer. Some studies have found that the expression of PER1 is altered in various types of cancer, including breast cancer and colorectal cancer, and that it may influence cancer cell growth and proliferation.

See also

• Circadian rhythm
• Period (gene)
• Cryptochrome
• Clock (gene)