Article
Biology
Suil Kim, Douglas G. McMahon
Summary: This study reveals that light input to the SCN can change the waveform of molecular clockworks, marking clock advances and delays at simulated dawn and dusk. The changes in waveform seem to be greatest in the ventrolateral SCN, while the effects on period are greatest in the dorsomedial SCN, suggesting spatiotemporally distinct responses within the SCN neural network.
Article
Cell Biology
Sabrina Klemz, Thomas Wallach, Sandra Korge, Mechthild Rosing, Roman Klemz, Bert Maier, Nicholas C. Fiorenza, Irem Kaymak, Anna K. Fritzsche, Erik D. Herzog, Ralf Stanewsky, Achim Kramer
Summary: In organisms with circadian clocks, the post-translational modifications of clock proteins, particularly phosphorylation, play a crucial role in controlling circadian rhythms. Protein phosphatase 4 (PPP4) and its regulatory subunit PPP4R2 have been identified as critical components in mammals and Drosophila, affecting the circadian system by regulating phosphorylation and transactivation activity of CLOCK/BMAL1.
GENES & DEVELOPMENT
(2021)
Article
Multidisciplinary Sciences
Yoshihiko Furuike, Atsushi Mukaiyama, Shin-Ichi Koda, Damien Simon, Dongyan Ouyang, Kumiko Ito-Miwa, Shinji Saito, Eiki Yamashita, Taeko Nishiwaki-Ohkawa, Kazuki Terauchi, Takao Kondo, Shuji Akiyama
Summary: KaiC is a dual ATPase that drives the circadian clock system of cyanobacteria through the coordination of its N-terminal and C-terminal active sites. The activities of these two sites are regulated differently and their delicate interactions drive the assembly and disassembly cycle of KaiA and KaiB.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Editorial Material
Cell Biology
Ueli Schibler
Summary: Mammalian body cells have cell-autonomous and self-sustained circadian oscillators relying on delayed negative feedback loops in gene expression. Transcriptional activation and repression, as well as post-translational mechanisms like phosphorylation and dephosphorylation, play crucial roles in setting the pace of these timekeepers. The study by Klemz and colleagues in Genes & Development demonstrates how dephosphorylation of BMAL1 by protein phosphatase 4 (PPP4) participates in the modulation of circadian timing.
GENES & DEVELOPMENT
(2021)
Article
Multidisciplinary Sciences
Mingxu Fang, Archana G. Chavan, Andy LiWang, Susan S. Golden
Summary: In this study, the researchers used the IVC reactions and massively parallel experiments to study entrainment, the synchronization of the circadian clock with the environment. The results showed that the IVC better explains the in vivo clock-resetting phenotypes of wild-type and mutant strains, and the output components are deeply engaged with the core oscillator, affecting the way input signals entrain the core pacemaker. These findings blur the line between input and output pathways and support the previous demonstration that key output components are fundamental parts of the clock.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Multidisciplinary Sciences
Kosaku Masuda, Isao T. Tokuda, Norihito Nakamichi, Hirokazu Fukuda
Summary: Circadian clocks enable organisms to synchronize physiological processes with diurnal variations, with the phase response curve being a key tool to understand clock entrainment. This study demonstrates that fundamental properties of the curve can be recovered from the singularity response, which can be easily measured by applying a single stimulus to a desynchronized cellular network. The method is simple, accurate, and applicable to other coupled oscillator systems, offering potential to study circadian clock entrainment in plants and other species in a cost-effective manner.
NATURE COMMUNICATIONS
(2021)
Editorial Material
Biochemistry & Molecular Biology
Michael J. Rust
Summary: The study on circadian clock suggests that it can function even in non-growing cells using minimal components from cyanobacteria. The findings indicate the potential evolution of the circadian clock to adapt to different cellular conditions.
Article
Agriculture, Dairy & Animal Science
C. Matamoros, I. J. Salfer, P. A. Bartell, K. J. Harvatine
Summary: This study investigated the effects of the timing of acetate infusion on peripheral rhythms of milk synthesis and plasma metabolites in dairy cows. The results showed that the timing of acetate infusion can influence the daily rhythms of milk synthesis and plasma metabolites in cows.
JOURNAL OF DAIRY SCIENCE
(2022)
Article
Multidisciplinary Sciences
Yoshihiko Furuike, Atsushi Mukaiyama, Dongyan Ouyang, Kumiko Ito-Miwa, Damien Simon, Eiki Yamashita, Takao Kondo, Shuji Akiyama
Summary: The study identifies the structural basis of spatiotemporal allostery in the cyanobacterial circadian clock and uncovers the important role of coil-to-helix transition and adenosine 5'-diphosphate release in maintaining the oscillatory nature.
Review
Medicine, Research & Experimental
Yi Qin, Zhong-hua Chen, Jun-Jie Wu, Zhen-Yu Zhang, Zheng-Dong Yuan, Dan-Yang Guo, Meng-Nan Chen, Xia Li, Feng-Lai Yuan
Summary: The circadian clock plays a crucial role in regulating bone metabolism, including bone loss. Clock-related genes control signaling pathways and transcription factors in osteoblasts and osteoclasts, while also regulating osteocytes and endothelial cells. Furthermore, the regulation of circadian clock genes by novel modulators presents a potential strategy for preventing and treating bone diseases.
BIOMEDICINE & PHARMACOTHERAPY
(2023)
Article
Biochemistry & Molecular Biology
Xiaomeng Liu, Niuben Cao, Xinchan Liu, Yu Deng, Yu Xin, Ruobing Fu, Xirui Xin, Yubo Hou, Weixian Yu
Summary: Circadian rhythms play a crucial role in regulating the body's homeostasis, and circadian rhythm disorders can have detrimental effects on metabolic and immune functions. However, the relationship between circadian rhythm disorders and periodontitis has not been well studied. This research aimed to investigate the role of the circadian rhythm control gene BMAL1 in periodontitis. The results showed that downregulation of BMAL1 in circadian rhythm disorder-induced periodontitis led to significant alveolar bone resorption, increased osteoclast differentiation, upregulation of the inflammatory signaling molecule NF-kappa B, elevated apoptosis and oxidative stress levels in periodontal tissues. This study suggests that BMAL1 is a key regulator in periodontitis exacerbated by circadian rhythm disorders, highlighting a potential avenue for periodontitis treatment.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Review
Biochemistry & Molecular Biology
Anna Ashton, Russell G. Foster, Aarti Jagannath
Summary: Circadian rhythms are essential for survival, allowing organisms to predict environmental changes and time behavior. The circadian clock is a self-sustaining molecular oscillator that needs to be continually adjusted to stay in alignment with the external world. Light is the primary time cue in mammals and plays a complex role in entraining the circadian clock in the SCN.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Multidisciplinary Sciences
Annika F. Barber, Shi Yi Fong, Anna Kolesnik, Michael Fetchko, Amita Sehgal
Summary: Regulation of circadian behavior and physiology by the Drosophila brain clock requires communication from central clock neurons to downstream output regions. Morning and evening clock neurons have time-of-day-dependent connectivity to the pars intercerebralis, which is regulated by specific peptides and fast neurotransmitters. This study provides insights into mechanisms by which clock neurons signal to nonclock cells to drive rhythms of behavior.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Review
Biochemistry & Molecular Biology
Rajesh Narasimamurthy, David M. Virshup
Summary: In our modern society, the consequences of disrupting our circadian rhythms by skipping or delaying sleep are severe, leading to various disorders. The internal clock is regulated by the reversible phosphorylation of PERIOD proteins, controlled by isoforms of casein kinase 1 (CK1). Through biochemical, genetic, and structural studies, a better understanding of how the core clock is regulated has been achieved, opening new approaches for clock regulation.
Review
Cell Biology
Zainab Taleb, Phillip Karpowicz
Summary: The circadian clock is a molecular timekeeper that regulates 24-hour rhythms in animals, impacting behavior and physiology, including metabolic and digestive systems. Animal models targeting circadian clock genes have shown their role in regulating liver diseases, inflammatory bowel disease, colorectal cancer, and obesity. Thus, the circadian clock plays a crucial role in maintaining metabolic and digestive health.
AMERICAN JOURNAL OF PHYSIOLOGY-CELL PHYSIOLOGY
(2022)
