2. Academic Validation
  3. E3 ubiquitin ligase UBR5 modulates circadian rhythm by facilitating the ubiquitination and degradation of the key clock transcription factor BMAL1

E3 ubiquitin ligase UBR5 modulates circadian rhythm by facilitating the ubiquitination and degradation of the key clock transcription factor BMAL1

  • Acta Pharmacol Sin. 2024 May 13. doi: 10.1038/s41401-024-01290-z.
Chunyan Duan 1 2,  Yue Li 1,  Haoyu Zhi 1,  Yao Tian 3,  Zhengyun Huang 4,  Suping Chen 1,  Yang Zhang 1,  Qing Liu 1,  Liang Zhou 1,  Xiaogang Jiang 1,  Kifayat Ullah 1,  Qing Guo 5,  Zhaohui Liu 5,  Ying Xu 4,  Junhai Han 3,  Jiajie Hou 6,  Darran P O'Connor 2,  Guo Qiang Xu 7 8 9
Affiliations

Affiliations

  • 1 Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Jiangsu Province Engineering Research Center of Precision Diagnostics and Therapeutics Development, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Suzhou Key Laboratory of Drug Research for Prevention and Treatment of Hyperlipidemic Diseases, Soochow University, Suzhou, 215123, China.
  • 2 School of Pharmacy and Biomolecular Sciences, RCSI University of Medicine and Health Sciences, 123 St Stephen's Green, Dublin 2, D02 YN77, Dublin, Ireland.
  • 3 School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing, 210096, China.
  • 4 Jiangsu Key Laboratory of Neuropsychiatric Diseases and Cambridge-Suda Genomic Resource Center, Soochow University, Suzhou, 215123, China.
  • 5 Department of Human Anatomy and Cytoneurobiology, Medical School of Soochow University, Suzhou, 215123, China.
  • 6 Cancer Centre, Faculty of Health Sciences, University of Macau, Macau SAR, China.
  • 7 Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Jiangsu Province Engineering Research Center of Precision Diagnostics and Therapeutics Development, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Suzhou Key Laboratory of Drug Research for Prevention and Treatment of Hyperlipidemic Diseases, Soochow University, Suzhou, 215123, China. gux2002@suda.edu.cn.
  • 8 Suzhou International Joint Laboratory for Diagnosis and Treatment of Brain Diseases, College of Pharmaceutical Sciences, Soochow University, Suzhou, 215123, China. gux2002@suda.edu.cn.
  • 9 MOE Key Laboratory of Geriatric Diseases and Immunology, Suzhou Medical College of Soochow University, Suzhou, 215123, China. gux2002@suda.edu.cn.
PMID: 38740904 DOI: 10.1038/s41401-024-01290-z
Abstract

The circadian clock is the inner rhythm of life activities and is controlled by a self-sustained and endogenous molecular clock, which maintains a ~ 24 h internal oscillation. As the core element of the circadian clock, BMAL1 is susceptible to degradation through the ubiquitin-proteasome system (UPS). Nevertheless, scant information is available regarding the UPS Enzymes that intricately modulate both the stability and transcriptional activity of BMAL1, affecting the cellular circadian rhythm. In this work, we identify and validate UBR5 as a new E3 ubiquitin Ligase that interacts with BMAL1 by using affinity purification, mass spectrometry, and biochemical experiments. UBR5 overexpression induced BMAL1 ubiquitination, leading to diminished stability and reduced protein level of BMAL1, thereby attenuating its transcriptional activity. Consistent with this, UBR5 knockdown increases the BMAL1 protein. Domain mapping discloses that the C-terminus of BMAL1 interacts with the N-terminal domains of UBR5. Similarly, cell-line-based experiments discover that HYD, the UBR5 homolog in Drosophila, could interact with and downregulate CYCLE, the BMAL1 homolog in Drosophila. PER2-luciferase bioluminescence real-time reporting assay in a mammalian cell line and behavioral experiments in Drosophila reveal that UBR5 or hyd knockdown significantly reduces the period of the circadian clock. Therefore, our work discovers a new ubiquitin Ligase UBR5 that regulates BMAL1 stability and circadian rhythm and elucidates the underlying molecular mechanism. This work provides an additional layer of complexity to the regulatory network of the circadian clock at the post-translational modification, offering potential insights into the modulation of the dysregulated circadian rhythm.

Keywords

BMAL1; UBR5; circadian rhythm; proteomics; transcriptional activity; ubiquitination.

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