JMJD5 links CRY1 function and proteasomal degradation.

Area of Science:

• Molecular Biology
• Chronobiology
• Biochemistry

Background:

• Circadian rhythms rely on precise posttranslational control of core oscillator components.
• Controlled proteolysis is crucial for circadian protein turnover, but mechanisms are not fully understood.

Purpose of the Study:

• To investigate the role of JMJD5 in the posttranslational regulation of CRY1 and its impact on circadian clock function.
• To elucidate the mechanism by which JMJD5 facilitates CRY1 degradation.

Main Methods:

• Co-immunoprecipitation assays to study protein-protein interactions (JMJD5, CRY1, FBXL3).
• Western blotting to assess protein stability and proteasomal degradation.
• Quantitative PCR to analyze circadian gene expression.
• Genetic deletion of JMJD5 in mice.

Main Results:

• JMJD5 interacts with CRY1 in an FBXL3-dependent manner, promoting CRY1 proteasomal targeting.
• JMJD5 deletion leads to increased CRY1 stability, reduced proteasome association, and disrupted circadian gene expression.
• AMPK-induced CRY1 degradation is impaired without JMJD5.
• JMJD5 facilitates CRY1-mediated repression of CLOCK/BMAL1 and impacts other FBXL3/CRY1 functions.

Conclusions:

• JMJD5 is essential for CRY1 destabilization and proper circadian oscillator function.
• JMJD5 acts as a key regulator in AMPK-induced CRY1 degradation.
• JMJD5 links CRY1 destabilization to its repressive function on CLOCK/BMAL1 and influences broader cellular processes.