CRY2

CRY2

CRY2 (Cryptochrome Circadian Regulator 2) is a protein encoded by the CRY2 gene in humans. It is a crucial component of the circadian clock, which regulates the daily rhythms of biological processes in organisms.

Structure

CRY2 is a flavoprotein that shares structural similarities with photolyases, a class of proteins involved in DNA repair. However, unlike photolyases, CRY2 does not have DNA repair activity. The protein consists of a photolyase homology region (PHR) and a C-terminal extension that is important for its function in the circadian clock.

Function

CRY2 plays a vital role in the regulation of circadian rhythms by acting as a transcriptional repressor. It forms a complex with PER proteins and translocates into the nucleus, where it inhibits the activity of the CLOCK and BMAL1 transcription factors. This inhibition is a key part of the feedback loop that generates circadian rhythms.

Mechanism

The circadian clock is driven by transcriptional-translational feedback loops. During the day, CLOCK and BMAL1 activate the transcription of PER and CRY genes. As PER and CRY proteins accumulate, they form complexes that enter the nucleus and inhibit CLOCK-BMAL1 activity, reducing their own transcription. This negative feedback loop results in oscillations of PER and CRY protein levels, which are essential for maintaining a 24-hour cycle.

Clinical Significance

Mutations or alterations in the CRY2 gene have been associated with various disorders, including sleep phase disorders and mood disorders. Understanding the role of CRY2 in the circadian clock can provide insights into the treatment of these conditions.

Research

Recent studies have explored the role of CRY2 in cancer biology, as circadian disruption is linked to cancer progression. CRY2 has been shown to influence cell cycle regulation and apoptosis, making it a potential target for cancer therapy.

See Also

• Circadian rhythm
• Cryptochrome
• PER (period circadian protein)
• CLOCK

External Links

• CRY2 Gene - NCBI
• CRY2 Protein - UniProt