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Chae SJ, Kim DW, Igoshin OA, Lee S, Kim JK. Beyond microtubules: The cellular environment at the endoplasmic reticulum attracts proteins to the nucleus, enabling nuclear transport. iScience 2024; 27:109235. [PMID: 38439967 PMCID: PMC10909898 DOI: 10.1016/j.isci.2024.109235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 01/03/2024] [Accepted: 02/09/2024] [Indexed: 03/06/2024] Open
Abstract
All proteins are translated in the cytoplasm, yet many, including transcription factors, play vital roles in the nucleus. While previous research has concentrated on molecular motors for the transport of these proteins to the nucleus, recent observations reveal perinuclear accumulation even in the absence of an energy source, hinting at alternative mechanisms. Here, we propose that structural properties of the cellular environment, specifically the endoplasmic reticulum (ER), can promote molecular transport to the perinucleus without requiring additional energy expenditure. Specifically, physical interaction between proteins and the ER impedes their diffusion and leads to their accumulation near the nucleus. This result explains why larger proteins, more frequently interacting with the ER membrane, tend to accumulate at the perinucleus. Interestingly, such diffusion in a heterogeneous environment follows Chapman's law rather than the popular Fick's law. Our findings suggest a novel protein transport mechanism arising solely from characteristics of the intracellular environment.
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Affiliation(s)
- Seok Joo Chae
- Department of Mathematical Sciences, KAIST, Daejeon 34141, Republic of Korea
- Biomedical Mathematics Group, Pioneer Research Center for Mathematical and Computational Sciences, Institute for Basic Science, Daejeon 34126, Republic of Korea
| | - Dae Wook Kim
- Department of Mathematics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Oleg A. Igoshin
- Department of Bioengineering, Rice University, Houston, TX 77005, USA
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, USA
- Department of Chemistry, Rice University, Houston, TX 77005, USA
- Department of Biosciences, Rice University, Houston, TX 77005, USA
| | - Seunggyu Lee
- Biomedical Mathematics Group, Pioneer Research Center for Mathematical and Computational Sciences, Institute for Basic Science, Daejeon 34126, Republic of Korea
- Division of Applied Mathematical Sciences, Korea University, Sejong 30019, Republic of Korea
| | - Jae Kyoung Kim
- Department of Mathematical Sciences, KAIST, Daejeon 34141, Republic of Korea
- Biomedical Mathematics Group, Pioneer Research Center for Mathematical and Computational Sciences, Institute for Basic Science, Daejeon 34126, Republic of Korea
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2
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Kou L, Chi X, Sun Y, Yin S, Wu J, Zou W, Wang Y, Jin Z, Huang J, Xiong N, Xia Y, Wang T. Circadian regulation of microglia function: Potential targets for treatment of Parkinson's Disease. Ageing Res Rev 2024; 95:102232. [PMID: 38364915 DOI: 10.1016/j.arr.2024.102232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 02/11/2024] [Accepted: 02/11/2024] [Indexed: 02/18/2024]
Abstract
Circadian rhythms are involved in the regulation of many aspects of the body, including cell function, physical activity and disease. Circadian disturbance often predates the typical symptoms of neurodegenerative diseases and is not only a non-motor symptom, but also one of the causes of their occurrence and progression. Glial cells possess circadian clocks that regulate their function to maintain brain development and homeostasis. Emerging evidence suggests that the microglial circadian clock is involved in the regulation of many physiological processes, such as cytokine release, phagocytosis, and nutritional and metabolic support, and that disruption of the microglia clock may affect multiple aspects of Parkinson's disease, especially neuroinflammation and α-synuclein processes. Herein, we review recent advances in the circadian control of microglia function in health and disease, and discuss novel pharmacological interventions for microglial clocks in neurodegenerative disorders.
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Affiliation(s)
- Liang Kou
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Xiaosa Chi
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Yadi Sun
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Sijia Yin
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Jiawei Wu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Wenkai Zou
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Yiming Wang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Zongjie Jin
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Jinsha Huang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Nian Xiong
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Yun Xia
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
| | - Tao Wang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
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3
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Song YM, Campbell S, Shiau L, Kim JK, Ott W. Noisy Delay Denoises Biochemical Oscillators. Phys Rev Lett 2024; 132:078402. [PMID: 38427894 DOI: 10.1103/physrevlett.132.078402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 11/17/2023] [Indexed: 03/03/2024]
Abstract
Genetic oscillations are generated by delayed transcriptional negative feedback loops, wherein repressor proteins inhibit their own synthesis after a temporal production delay. This delay is distributed because it arises from a sequence of noisy processes, including transcription, translocation, translation, and folding. Because the delay determines repression timing and, therefore, oscillation period, it has been commonly believed that delay noise weakens oscillatory dynamics. Here, we demonstrate that noisy delay can surprisingly denoise genetic oscillators. Specifically, moderate delay noise improves the signal-to-noise ratio and sharpens oscillation peaks, all without impacting period and amplitude. We show that this denoising phenomenon occurs in a variety of well-studied genetic oscillators, and we use queueing theory to uncover the universal mechanisms that produce it.
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Affiliation(s)
- Yun Min Song
- Department of Mathematical Sciences, KAIST, Daejeon 34141, Republic of Korea
- Biomedical Mathematics Group, Pioneer Research Center for Mathematical and Computational Sciences, Institute for Basic Science, Daejeon 34126, Republic of Korea
| | - Sean Campbell
- Department of Mathematics, University of Houston, Houston, Texas 77204, USA
| | - LieJune Shiau
- Department of Mathematics and Statistics, University of Houston Clear Lake, Houston, Texas 77058, USA
| | - Jae Kyoung Kim
- Department of Mathematical Sciences, KAIST, Daejeon 34141, Republic of Korea
- Biomedical Mathematics Group, Pioneer Research Center for Mathematical and Computational Sciences, Institute for Basic Science, Daejeon 34126, Republic of Korea
| | - William Ott
- Department of Mathematics, University of Houston, Houston, Texas 77204, USA
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4
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Sharma D, Partch CL. PAS Dimerization at the Nexus of the Mammalian Circadian Clock. J Mol Biol 2024; 436:168341. [PMID: 37924861 DOI: 10.1016/j.jmb.2023.168341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 10/23/2023] [Accepted: 10/29/2023] [Indexed: 11/06/2023]
Abstract
Circadian rhythms are genetically encoded molecular clocks for internal biological timekeeping. Organisms from single-cell bacteria to humans use these clocks to adapt to the external environment and synchronize their physiology and behavior to solar light/dark cycles. Although the proteins that constitute the molecular 'cogs' and give rise to circadian rhythms are now known, we still lack a detailed understanding of how these proteins interact to generate and sustain the ∼24-hour circadian clock. Structural studies have helped to expand the architecture of clock proteins and have revealed the abundance of the only well-defined structured regions in the mammalian clock called Per-ARNT-Sim (PAS) domains. PAS domains are modular, evolutionarily conserved sensory and signaling domains that typically mediate protein-protein interactions. In the mammalian circadian clock, PAS domains modulate homo and heterodimerization of several core clock proteins that assemble into transcription factors or repressors. This review will focus on the functional importance of the PAS domains in the circadian clock from a biophysical and biochemical standpoint and describe their roles in clock protein interactions and circadian timekeeping.
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Affiliation(s)
- Diksha Sharma
- Department of Chemistry and Biochemistry, University of California Santa Cruz, CA, United States
| | - Carrie L Partch
- Department of Chemistry and Biochemistry, University of California Santa Cruz, CA, United States; Center for Circadian Biology, University of California San Diego, CA, United States.
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5
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Del Olmo M, Kalashnikov A, Schmal C, Kramer A, Herzel H. Coupling allows robust mammalian redox circadian rhythms despite heterogeneity and noise. Heliyon 2024; 10:e24773. [PMID: 38312577 PMCID: PMC10835301 DOI: 10.1016/j.heliyon.2024.e24773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 12/06/2023] [Accepted: 01/14/2024] [Indexed: 02/06/2024] Open
Abstract
Circadian clocks are endogenous oscillators present in almost all cells that drive daily rhythms in physiology and behavior. There are two mechanisms that have been proposed to explain how circadian rhythms are generated in mammalian cells: through a transcription-translation feedback loop (TTFL) and based on oxidation/reduction reactions, both of which are intrinsically stochastic and heterogeneous at the single cell level. In order to explore the emerging properties of stochastic and heterogeneous redox oscillators, we simplify a recently developed kinetic model of redox oscillations to an amplitude-phase oscillator with 'twist' (period-amplitude correlation) and subject to Gaussian noise. We show that noise and heterogeneity alone lead to fast desynchronization, and that coupling between noisy oscillators can establish robust and synchronized rhythms with amplitude expansions and tuning of the period due to twist. Coupling a network of redox oscillators to a simple model of the TTFL also contributes to synchronization, large amplitudes and fine-tuning of the period for appropriate interaction strengths. These results provide insights into how the circadian clock compensates randomness from intracellular sources and highlight the importance of noise, heterogeneity and coupling in the context of circadian oscillators.
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Affiliation(s)
- Marta Del Olmo
- Institute for Theoretical Biology - Humboldt Universität zu Berlin and Charité Universitätsmedizin Berlin, Philippstraße 13, 10115 Berlin, Germany
| | - Anton Kalashnikov
- Institute for Theoretical Biology - Humboldt Universität zu Berlin and Charité Universitätsmedizin Berlin, Philippstraße 13, 10115 Berlin, Germany
| | - Christoph Schmal
- Institute for Theoretical Biology - Humboldt Universität zu Berlin and Charité Universitätsmedizin Berlin, Philippstraße 13, 10115 Berlin, Germany
| | - Achim Kramer
- Institute for Medical Immunology - Laboratory of Chronobiology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Hanspeter Herzel
- Institute for Theoretical Biology - Humboldt Universität zu Berlin and Charité Universitätsmedizin Berlin, Philippstraße 13, 10115 Berlin, Germany
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6
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Laothamatas I, Rasmussen ES, Green CB, Takahashi JS. Metabolic and chemical architecture of the mammalian circadian clock. Cell Chem Biol 2023; 30:1033-1052. [PMID: 37708890 PMCID: PMC10631358 DOI: 10.1016/j.chembiol.2023.08.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 07/20/2023] [Accepted: 08/23/2023] [Indexed: 09/16/2023]
Abstract
Circadian rhythms are endogenous periodic biological processes that occur on a daily timescale. These rhythms are generated by a transcriptional/translational feedback loop that consists of the CLOCK-BMAL1 heterodimeric transcriptional activator complex and the PER1/2-CRY1/2-CK1δ/ε repressive complex. The output pathways of this molecular feedback loop generate circadian rhythmicity in various biological processes. Among these, metabolism is a primary regulatory target of the circadian clock which can also feedback to modulate clock function. This intertwined relationship between circadian rhythms and metabolism makes circadian clock components promising therapeutic targets. Despite this, pharmacological therapeutics that target the circadian clock are relatively rare. In this review, we hope to stimulate interest in chemical chronobiology by providing a comprehensive background on the molecular mechanism of mammalian circadian rhythms and their connection to metabolism, highlighting important studies in the chemical approach to circadian research, and offering our perspectives on future developments in the field.
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Affiliation(s)
- Isara Laothamatas
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Emil Sjulstok Rasmussen
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Carla B Green
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Joseph S Takahashi
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA; Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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7
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Jung J, Kang J, Kim T. Attenuation of homeostatic sleep response and rest-activity circadian rhythm in vitamin D deficient mice. Chronobiol Int 2023; 40:1097-1110. [PMID: 37661839 DOI: 10.1080/07420528.2023.2253299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/09/2023] [Accepted: 08/24/2023] [Indexed: 09/05/2023]
Abstract
The link between vitamin D deficiency (VDD) and sleep disturbances has long been suggested. However, the direct causality between VDD, sleep disturbances, and circadian rhythm remains unclear. We aimed to characterize sleep-wake behavior and circadian rhythms in an animal model of VDD. VDD was induced by feeding vitamin D-deficient chow, and we analyzed sleep and circadian rhythm parameters. During light period, VDD mice exhibited reduced wake with more frequent wake bouts and increased NREM sleep time. However, during dark period, the wake EEG power spectrum peaked at theta band frequency, and slow-wave energy was suppressed in mice with VDD. Rest-activity analyses revealed increased circadian period, lower wheel counts, and more frequent and short activity bouts during VDD. Combining sleep and circadian data, we found significantly suppressed activities during the hours with a wake duration shorter than 30 minutes. Moreover, mice in VDD state exhibited a negative correlation between wake theta power and hourly wheel-running counts during dark period. Our data point to a direct link between VDD and disturbances in sleep and rest-activity circadian rhythm, featuring frequent wake bouts during the sleeping phase, reduced sleep pressure build-up in dark period, and reduced activity levels due to increased susceptibility to sleepiness.
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Affiliation(s)
- Jieun Jung
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
| | - Jiseung Kang
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
| | - Tae Kim
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
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8
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Philpott JM, Freeberg AM, Park J, Lee K, Ricci CG, Hunt SR, Narasimamurthy R, Segal DH, Robles R, Cai Y, Tripathi S, McCammon JA, Virshup DM, Chiu JC, Lee C, Partch CL. PERIOD phosphorylation leads to feedback inhibition of CK1 activity to control circadian period. Mol Cell 2023; 83:1677-1692.e8. [PMID: 37207626 DOI: 10.1016/j.molcel.2023.04.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 02/16/2023] [Accepted: 04/19/2023] [Indexed: 05/21/2023]
Abstract
PERIOD (PER) and Casein Kinase 1δ regulate circadian rhythms through a phosphoswitch that controls PER stability and repressive activity in the molecular clock. CK1δ phosphorylation of the familial advanced sleep phase (FASP) serine cluster embedded within the Casein Kinase 1 binding domain (CK1BD) of mammalian PER1/2 inhibits its activity on phosphodegrons to stabilize PER and extend circadian period. Here, we show that the phosphorylated FASP region (pFASP) of PER2 directly interacts with and inhibits CK1δ. Co-crystal structures in conjunction with molecular dynamics simulations reveal how pFASP phosphoserines dock into conserved anion binding sites near the active site of CK1δ. Limiting phosphorylation of the FASP serine cluster reduces product inhibition, decreasing PER2 stability and shortening circadian period in human cells. We found that Drosophila PER also regulates CK1δ via feedback inhibition through the phosphorylated PER-Short domain, revealing a conserved mechanism by which PER phosphorylation near the CK1BD regulates CK1 kinase activity.
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Affiliation(s)
- Jonathan M Philpott
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Alfred M Freeberg
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Jiyoung Park
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA
| | - Kwangjun Lee
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA
| | - Clarisse G Ricci
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sabrina R Hunt
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Rajesh Narasimamurthy
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore 169857, Singapore
| | - David H Segal
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Rafael Robles
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Yao Cai
- Department of Entomology and Nematology, University of California, Davis, Davis, CA 95616, USA
| | - Sarvind Tripathi
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - J Andrew McCammon
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA; Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - David M Virshup
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore 169857, Singapore; Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA
| | - Joanna C Chiu
- Department of Entomology and Nematology, University of California, Davis, Davis, CA 95616, USA
| | - Choogon Lee
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA.
| | - Carrie L Partch
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA; Center for Circadian Biology, University of California, San Diego, La Jolla, CA 92093, USA.
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Pelham JF, Mosier AE, Altshuler SC, Rhodes ML, Kirchhoff CL, Fall WB, Mann C, Baik LS, Chiu JC, Hurley JM. Conformational changes in the negative arm of the circadian clock correlate with dynamic interactomes involved in post-transcriptional regulation. Cell Rep 2023; 42:112376. [PMID: 37043358 PMCID: PMC10562519 DOI: 10.1016/j.celrep.2023.112376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 09/16/2022] [Accepted: 03/24/2023] [Indexed: 04/13/2023] Open
Abstract
Biology is tuned to the Earth's diurnal cycle by the circadian clock, a transcriptional/translational negative feedback loop that regulates physiology via transcriptional activation and other post-transcriptional mechanisms. We hypothesize that circadian post-transcriptional regulation might stem from conformational shifts in the intrinsically disordered proteins that comprise the negative arm of the feedback loop to coordinate variation in negative-arm-centered macromolecular complexes. This work demonstrates temporal conformational fluidity in the negative arm that correlates with 24-h variation in physiologically diverse macromolecular complex components in eukaryotic clock proteins. Short linear motifs on the negative-arm proteins that correspond with the interactors localized to disordered regions and known temporal phosphorylation sites suggesting changes in these macromolecular complexes could be due to conformational changes imparted by the temporal phospho-state. Interactors that oscillate in the macromolecular complexes over circadian time correlate with post-transcriptionally regulated proteins, highlighting how time-of-day variation in the negative-arm protein complexes may tune cellular physiology.
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Affiliation(s)
- Jacqueline F Pelham
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Alexander E Mosier
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Samuel C Altshuler
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Morgan L Rhodes
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | | | - William B Fall
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Catherine Mann
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Lisa S Baik
- Department of Entomology and Nematology, University of California, Davis, Davis, CA 95616, USA
| | - Joanna C Chiu
- Department of Entomology and Nematology, University of California, Davis, Davis, CA 95616, USA
| | - Jennifer M Hurley
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA; Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
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10
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Park J, Lee K, Kim H, Shin H, Lee C. Endogenous circadian reporters reveal functional differences of PERIOD paralogs and the significance of PERIOD:CK1 stable interaction. Proc Natl Acad Sci U S A 2023; 120:e2212255120. [PMID: 36724252 DOI: 10.1073/pnas.2212255120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Adverse consequences from having a faulty circadian clock include compromised sleep quality and poor performance in the short-term, and metabolic diseases and cancer in the long-term. However, our understanding of circadian disorders is limited by the incompleteness of our molecular models and our dearth of defined mutant models. Because it would be prohibitively expensive to develop live animal models to study the full range of complicated clock mechanisms, we developed PER1-luc and PER2-luc endogenous circadian reporters in a validated clock cell model, U-2 OS, where the genome can be easily manipulated, and functional consequences of mutations can be accurately studied. When major clock genes were knocked out in these cells, circadian rhythms were modulated similarly compared with corresponding mutant mice, validating the platform for genetics studies. Using these reporter cells, we uncovered critical differences between two paralogs of PER. Although PER1 and PER2 are considered redundant and either one can serve as a pacemaker alone, they were dramatically different in biochemical parameters such as stability and phosphorylation kinetics. Consistently, circadian phase was dramatically different between PER1 and PER2 knockout reporter cells. We further showed that the stable binding of casein kinase1δ/ε to PER is not required for PER phosphorylation itself, but is critical for delayed timing of phosphorylation. Our system can be used as an efficient platform to study circadian disorders associated with pathogenic mutations and their underlying molecular mechanisms.
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11
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Gao D, Ma T, Gao L, Zhang J, Zhang H, Zhang L, Dong H, Li Y, Zhao L, Liu W, Zhao H, Li D, Zhou D, Wang A, Jin Y, Chen H. Autophagy activation attenuates the circadian clock oscillators in U2OS cells via the ATG5 pathway. Cell Signal 2023; 101:110502. [PMID: 36280090 DOI: 10.1016/j.cellsig.2022.110502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 09/30/2022] [Accepted: 10/17/2022] [Indexed: 11/28/2022]
Abstract
The circadian clock and autophagy are essential biological mechanisms involved in regulating many physiological processes. Accumulating evidence has revealed that autophagic activity is regulated by the circadian clock system. However, whether autophagy regulates the circadian clock system remains unclear. In this study, rapamycin and AICAR, two classical activators of autophagy, were used to create autophagy activation models in BMAL1-dLuc U2OS cell line. The results showed that the mRNA expression of MAP1LC3B and ATG5 were significantly upregulated after autophagy activation, whereas the mRNA expression of circadian clock genes (BMAL1, PER2, REV-ERBα, and DBP) were significantly decreased. Consistent with these data, the relative ratio of LC3-II/LC3-I and the protein level of ATG5 were increased after rapamycin or AICAR treatment. In contrast, BMAL1 and REV-ERBα levels were decreased. Notably, the mRNA expression of circadian clock genes (BMAL1, PER2, REV-ERBα, and DBP) and autophagy-related genes (MAP1LC3B and ATG5) showed rhythmic expression patterns in both untreated and rapamycin/AICAR-treated U2OS cells. Moreover, the autophagy inhibitor 3-methyladenine partially reversed the inhibitory effects of autophagy on circadian clock genes expression and BMAL1-Luc oscillations. Another critical finding was that ATG5 knockout alleviates the inhibitory effect of rapamycin-mediated autophagy activation on the circadian clock oscillators in U2OS cells. Collectively, our data indicate that autophagy activation attenuates the circadian clock oscillators in U2OS cells via the ATG5 pathway.
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Affiliation(s)
- Dengke Gao
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Tiantian Ma
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Lei Gao
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, Northwest A&F University, Yangling 712100, Shaanxi, China; College of Agriculture and Animal Husbandry, Qing Hai University, Xining, Qinghai, China
| | - Jing Zhang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Haisen Zhang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Linlin Zhang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Hao Dong
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Yating Li
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Lijia Zhao
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Wei Liu
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Hongcong Zhao
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Dan Li
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Dong Zhou
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Aihua Wang
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, Northwest A&F University, Yangling 712100, Shaanxi, China; Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Yaping Jin
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Huatao Chen
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, Northwest A&F University, Yangling 712100, Shaanxi, China.
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12
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Kelliher CM, Stevenson EL, Loros JJ, Dunlap JC. Nutritional compensation of the circadian clock is a conserved process influenced by gene expression regulation and mRNA stability. PLoS Biol 2023; 21:e3001961. [PMID: 36603054 PMCID: PMC9848017 DOI: 10.1371/journal.pbio.3001961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 01/18/2023] [Accepted: 12/15/2022] [Indexed: 01/06/2023] Open
Abstract
Compensation is a defining principle of a true circadian clock, where its approximately 24-hour period length is relatively unchanged across environmental conditions. Known compensation effectors directly regulate core clock factors to buffer the oscillator's period length from variables in the environment. Temperature Compensation mechanisms have been experimentally addressed across circadian model systems, but much less is known about the related process of Nutritional Compensation, where circadian period length is maintained across physiologically relevant nutrient levels. Using the filamentous fungus Neurospora crassa, we performed a genetic screen under glucose and amino acid starvation conditions to identify new regulators of Nutritional Compensation. Our screen uncovered 16 novel mutants, and together with 4 mutants characterized in prior work, a model emerges where Nutritional Compensation of the fungal clock is achieved at the levels of transcription, chromatin regulation, and mRNA stability. However, eukaryotic circadian Nutritional Compensation is completely unstudied outside of Neurospora. To test for conservation in cultured human cells, we selected top hits from our fungal genetic screen, performed siRNA knockdown experiments of the mammalian orthologs, and characterized the cell lines with respect to compensation. We find that the wild-type mammalian clock is also compensated across a large range of external glucose concentrations, as observed in Neurospora, and that knocking down the mammalian orthologs of the Neurospora compensation-associated genes CPSF6 or SETD2 in human cells also results in nutrient-dependent period length changes. We conclude that, like Temperature Compensation, Nutritional Compensation is a conserved circadian process in fungal and mammalian clocks and that it may share common molecular determinants.
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Affiliation(s)
- Christina M. Kelliher
- Department of Molecular & Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- Department of Biology, University of Massachusetts Boston, Boston, Massachusetts, United States of America
| | - Elizabeth-Lauren Stevenson
- Department of Molecular & Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Jennifer J. Loros
- Department of Biochemistry & Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Jay C. Dunlap
- Department of Molecular & Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
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13
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Jeong EM, Song YM, Kim JK. Combined multiple transcriptional repression mechanisms generate ultrasensitivity and oscillations. Interface Focus 2022; 12:20210084. [PMID: 35450279 PMCID: PMC9010851 DOI: 10.1098/rsfs.2021.0084] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 02/24/2022] [Indexed: 12/14/2022] Open
Abstract
Transcriptional repression can occur via various mechanisms, such as blocking, sequestration and displacement. For instance, the repressors can hold the activators to prevent binding with DNA or can bind to the DNA-bound activators to block their transcriptional activity. Although the transcription can be completely suppressed with a single mechanism, multiple repression mechanisms are used together to inhibit transcriptional activators in many systems, such as circadian clocks and NF-κB oscillators. This raises the question of what advantages arise if seemingly redundant repression mechanisms are combined. Here, by deriving equations describing the multiple repression mechanisms, we find that their combination can synergistically generate a sharply ultrasensitive transcription response and thus strong oscillations. This rationalizes why the multiple repression mechanisms are used together in various biological oscillators. The critical role of such combined transcriptional repression for strong oscillations is further supported by our analysis of formerly identified mutations disrupting the transcriptional repression of the mammalian circadian clock. The hitherto unrecognized source of the ultrasensitivity, the combined transcriptional repressions, can lead to robust synthetic oscillators with a previously unachievable simple design.
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Affiliation(s)
- Eui Min Jeong
- Department of Mathematical Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
- Biomedical Mathematics Group, Institute for Basic Science, Daejeon 34126, Republic of Korea
| | - Yun Min Song
- Department of Mathematical Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
- Biomedical Mathematics Group, Institute for Basic Science, Daejeon 34126, Republic of Korea
| | - Jae Kyoung Kim
- Department of Mathematical Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
- Biomedical Mathematics Group, Institute for Basic Science, Daejeon 34126, Republic of Korea
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14
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Kim DW, Hong H, Kim JK. Systematic inference identifies a major source of heterogeneity in cell signaling dynamics: The rate-limiting step number. Sci Adv 2022; 8:eabl4598. [PMID: 35302852 PMCID: PMC8932658 DOI: 10.1126/sciadv.abl4598] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 01/26/2022] [Indexed: 06/14/2023]
Abstract
Identifying the sources of cell-to-cell variability in signaling dynamics is essential to understand drug response variability and develop effective therapeutics. However, it is challenging because not all signaling intermediate reactions can be experimentally measured simultaneously. This can be overcome by replacing them with a single random time delay, but the resulting process is non-Markovian, making it difficult to infer cell-to-cell heterogeneity in reaction rates and time delays. To address this, we developed an efficient and scalable moment-based Bayesian inference method (MBI) with a user-friendly computational package that infers cell-to-cell heterogeneity in the non-Markovian signaling process. We applied MBI to single-cell expression profiles from promoters responding to antibiotics and discovered a major source of cell-to-cell variability in antibiotic stress response: the number of rate-limiting steps in signaling cascades. This knowledge can help identify effective therapies that destroy all pathogenic or cancer cells, and the approach can be applied to precision medicine.
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Affiliation(s)
- Dae Wook Kim
- Department of Mathematical Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
- Biomedical Mathematics Group, Institute for Basic Science, Daejeon 34126, Republic of Korea
| | - Hyukpyo Hong
- Department of Mathematical Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
- Biomedical Mathematics Group, Institute for Basic Science, Daejeon 34126, Republic of Korea
| | - Jae Kyoung Kim
- Department of Mathematical Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
- Biomedical Mathematics Group, Institute for Basic Science, Daejeon 34126, Republic of Korea
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15
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Kawakami S, Yoshitane H, Morimura T, Kimura W, Fukada Y. Diurnal shift of mouse activity by the deficiency of an aging-related gene Lmna. J Biochem 2022; 171:509-518. [PMID: 35137145 DOI: 10.1093/jb/mvac015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Accepted: 02/02/2022] [Indexed: 11/13/2022] Open
Abstract
Nuclear lamina is a fundamental structure of the cell nucleus and regulates a wide range of molecular pathways. Defects of components of the nuclear lamina cause aging-like physiological disorders, called laminopathy. Generally, aging and diseases are often associated with perturbation of various time-of-day-dependent regulations, but it remains still elusive whether laminopathy induces any changes of the circadian clock and physiological rhythms. Here we demonstrated that deficiency of Lmna gene in mice caused an obvious shift of locomotor activities to the daytime. The abnormal activity profile was accompanied by a remarkable change in phase-angle between the central clock in the suprachiasmatic nucleus (SCN) and lung peripheral clocks, leaving the phase of the SCN clock unaffected by the mutation. These observations suggest that Lmna deficiency causes a change of the habitat from nocturnal to diurnal behaviors. On the other hand, molecular oscillation and its phase resetting mechanism were intact in both the Lmna-deficient cells and progeria-mimicking cells. Intriguingly, high-fat diet feeding extended the short lifespan and ameliorated the abnormalities of the behaviors and the phase of the peripheral clock in the Lmna-deficient mice. The present study supports the important contribution of the energy conditions to a shift between the diurnal and nocturnal activities.
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Affiliation(s)
- Satoshi Kawakami
- Department of Biological Sciences, School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.,Circadian Clock Project, Tokyo Metropolitan Institute of Medical Science, Kamikitazawa 2-1-6, Setagaya-ku, Tokyo 156-8506, Japan
| | - Hikari Yoshitane
- Department of Biological Sciences, School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.,Circadian Clock Project, Tokyo Metropolitan Institute of Medical Science, Kamikitazawa 2-1-6, Setagaya-ku, Tokyo 156-8506, Japan
| | - Taiki Morimura
- Department of Biological Sciences, School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.,Circadian Clock Project, Tokyo Metropolitan Institute of Medical Science, Kamikitazawa 2-1-6, Setagaya-ku, Tokyo 156-8506, Japan
| | - Wataru Kimura
- RIKEN Center for Biosystems Dynamics Research, Minatojima-minamimachi 2-2-3, Chuo-ku, Kobe, Hyogo 650-0043, Japan
| | - Yoshitaka Fukada
- Department of Biological Sciences, School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.,Circadian Clock Project, Tokyo Metropolitan Institute of Medical Science, Kamikitazawa 2-1-6, Setagaya-ku, Tokyo 156-8506, Japan.,Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
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16
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Song YM, Hong H, Kim JK. Universally valid reduction of multiscale stochastic biochemical systems using simple non-elementary propensities. PLoS Comput Biol 2021; 17:e1008952. [PMID: 34662330 PMCID: PMC8562860 DOI: 10.1371/journal.pcbi.1008952] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 11/02/2021] [Accepted: 10/04/2021] [Indexed: 11/19/2022] Open
Abstract
Biochemical systems consist of numerous elementary reactions governed by the law of mass action. However, experimentally characterizing all the elementary reactions is nearly impossible. Thus, over a century, their deterministic models that typically contain rapid reversible bindings have been simplified with non-elementary reaction functions (e.g., Michaelis-Menten and Morrison equations). Although the non-elementary reaction functions are derived by applying the quasi-steady-state approximation (QSSA) to deterministic systems, they have also been widely used to derive propensities for stochastic simulations due to computational efficiency and simplicity. However, the validity condition for this heuristic approach has not been identified even for the reversible binding between molecules, such as protein-DNA, enzyme-substrate, and receptor-ligand, which is the basis for living cells. Here, we find that the non-elementary propensities based on the deterministic total QSSA can accurately capture the stochastic dynamics of the reversible binding in general. However, serious errors occur when reactant molecules with similar levels tightly bind, unlike deterministic systems. In that case, the non-elementary propensities distort the stochastic dynamics of a bistable switch in the cell cycle and an oscillator in the circadian clock. Accordingly, we derive alternative non-elementary propensities with the stochastic low-state QSSA, developed in this study. This provides a universally valid framework for simplifying multiscale stochastic biochemical systems with rapid reversible bindings, critical for efficient stochastic simulations of cell signaling and gene regulation. To facilitate the framework, we provide a user-friendly open-source computational package, ASSISTER, that automatically performs the present framework.
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Affiliation(s)
- Yun Min Song
- Department of Mathematical Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
- Biomedical Mathematics Group, Institute for Basic Science, Daejeon, Republic of Korea
| | - Hyukpyo Hong
- Department of Mathematical Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
- Biomedical Mathematics Group, Institute for Basic Science, Daejeon, Republic of Korea
| | - Jae Kyoung Kim
- Department of Mathematical Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
- Biomedical Mathematics Group, Institute for Basic Science, Daejeon, Republic of Korea
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17
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Goldbeter A, Leloup J. From circadian clock mechanism to sleep disorders and jet lag: Insights from a computational approach. Biochem Pharmacol 2021; 191:114482. [DOI: 10.1016/j.bcp.2021.114482] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 02/15/2021] [Accepted: 02/16/2021] [Indexed: 12/13/2022]
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18
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De Boeck J, Rombouts J, Gelens L. A modular approach for modeling the cell cycle based on functional response curves. PLoS Comput Biol 2021; 17:e1009008. [PMID: 34379640 DOI: 10.1371/journal.pcbi.1009008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 08/23/2021] [Accepted: 07/19/2021] [Indexed: 12/02/2022] Open
Abstract
Modeling biochemical reactions by means of differential equations often results in systems with a large number of variables and parameters. As this might complicate the interpretation and generalization of the obtained results, it is often desirable to reduce the complexity of the model. One way to accomplish this is by replacing the detailed reaction mechanisms of certain modules in the model by a mathematical expression that qualitatively describes the dynamical behavior of these modules. Such an approach has been widely adopted for ultrasensitive responses, for which underlying reaction mechanisms are often replaced by a single Hill function. Also time delays are usually accounted for by using an explicit delay in delay differential equations. In contrast, however, S-shaped response curves, which by definition have multiple output values for certain input values and are often encountered in bistable systems, are not easily modeled in such an explicit way. Here, we extend the classical Hill function into a mathematical expression that can be used to describe both ultrasensitive and S-shaped responses. We show how three ubiquitous modules (ultrasensitive responses, S-shaped responses and time delays) can be combined in different configurations and explore the dynamics of these systems. As an example, we apply our strategy to set up a model of the cell cycle consisting of multiple bistable switches, which can incorporate events such as DNA damage and coupling to the circadian clock in a phenomenological way. Bistability plays an important role in many biochemical processes and typically emerges from complex interaction patterns such as positive and double negative feedback loops. Here, we propose to theoretically study the effect of bistability in a larger interaction network. We explicitly incorporate a functional expression describing an S-shaped input-output curve in the model equations, without the need for considering the underlying biochemical events. This expression can be converted into a functional module for an ultrasensitive response, and a time delay is easily included as well. Exploiting the fact that several of these modules can easily be combined in larger networks, we construct a cell cycle model consisting of multiple bistable switches and show how this approach can account for a number of known properties of the cell cycle.
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19
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Lim R, Chae J, Somers DE, Ghim CM, Kim PJ. Cost-effective circadian mechanism: rhythmic degradation of circadian proteins spontaneously emerges without rhythmic post-translational regulation. iScience 2021; 24:102726. [PMID: 34355141 PMCID: PMC8324817 DOI: 10.1016/j.isci.2021.102726] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 05/10/2021] [Accepted: 06/11/2021] [Indexed: 12/20/2022] Open
Abstract
Circadian protein oscillations are maintained by the lifelong repetition of protein production and degradation in daily balance. It comes at the cost of ever-replayed, futile protein synthesis each day. This biosynthetic cost with a given oscillatory protein profile is relievable by a rhythmic, not constant, degradation rate that selectively peaks at the right time of day but remains low elsewhere, saving much of the gross protein loss and of the replenishing protein synthesis. Here, our mathematical modeling reveals that the rhythmic degradation rate of proteins with circadian production spontaneously emerges under steady and limited activity of proteolytic mediators and does not necessarily require rhythmic post-translational regulation of previous focus. Additional (yet steady) post-translational modifications in a proteolytic pathway can further facilitate the degradation's rhythmicity in favor of the biosynthetic cost saving. Our work is supported by animal and plant circadian data, offering a generic mechanism for potentially widespread, time-dependent protein turnover. Rhythmic degradation of circadian proteins lowers the cost of protein synthesis This rhythmic degradation emerges without rhythmic post-translational regulation Extra, yet steady post-translational modifications enhance degradation rhythmicity This mechanism hints at how organisms afford the price of daily biological rhythms
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Affiliation(s)
- Roktaek Lim
- Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong
| | - Junghun Chae
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - David E Somers
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA.,Center for Applied Plant Sciences, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Arabidopsis Biological Resource Center, The Ohio State University, Columbus, OH 43210, USA
| | - Cheol-Min Ghim
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea.,Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Pan-Jun Kim
- Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong.,Center for Quantitative Systems Biology & Institute of Computational and Theoretical Studies, Hong Kong Baptist University, Kowloon, Hong Kong.,State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University, Kowloon, Hong Kong.,Abdus Salam International Centre for Theoretical Physics, 34151 Trieste, Italy
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20
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Philpott JM, Torgrimson MR, Harold RL, Partch CL. Biochemical mechanisms of period control within the mammalian circadian clock. Semin Cell Dev Biol 2021; 126:71-78. [PMID: 33933351 DOI: 10.1016/j.semcdb.2021.04.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 04/11/2021] [Accepted: 04/13/2021] [Indexed: 12/27/2022]
Abstract
Genetically encoded biological clocks are found broadly throughout life on Earth, where they generate circadian (about a day) rhythms that synchronize physiology and behavior with the daily light/dark cycle. Although the genetic networks that give rise to circadian timing are now fairly well established, our understanding of how the proteins that constitute the molecular 'cogs' of this biological clock regulate the intrinsic timing, or period, of circadian rhythms has lagged behind. New studies probing the biochemical and structural basis of clock protein function are beginning to reveal how assemblies of dedicated clock proteins form and evolve through post-translational regulation to generate circadian rhythms. This review will highlight some recent advances providing important insight into the molecular mechanisms of period control in mammalian clocks with an emphasis on structural analyses related to CK1-dependent control of PER stability.
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Affiliation(s)
- Jonathan M Philpott
- Department of Chemistry and Biochemistry, UC Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA.
| | - Megan R Torgrimson
- Department of Chemistry and Biochemistry, UC Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA.
| | - Rachel L Harold
- Department of Chemistry and Biochemistry, UC Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA.
| | - Carrie L Partch
- Department of Chemistry and Biochemistry, UC Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA; Center for Circadian Biology, UC San Diego, 9500 Gilman Drive, MC 0116, La Jolla, CA 92093, USA.
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21
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Carter B, Justin HS, Gulick D, Gamsby JJ. The Molecular Clock and Neurodegenerative Disease: A Stressful Time. Front Mol Biosci 2021; 8:644747. [PMID: 33889597 PMCID: PMC8056266 DOI: 10.3389/fmolb.2021.644747] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 03/01/2021] [Indexed: 12/14/2022] Open
Abstract
Circadian rhythm dysfunction occurs in both common and rare neurodegenerative diseases. This dysfunction manifests as sleep cycle mistiming, alterations in body temperature rhythms, and an increase in symptomatology during the early evening hours known as Sundown Syndrome. Disruption of circadian rhythm homeostasis has also been implicated in the etiology of neurodegenerative disease. Indeed, individuals exposed to a shifting schedule of sleep and activity, such as health care workers, are at a higher risk. Thus, a bidirectional relationship exists between the circadian system and neurodegeneration. At the heart of this crosstalk is the molecular circadian clock, which functions to regulate circadian rhythm homeostasis. Over the past decade, this connection has become a focal point of investigation as the molecular clock offers an attractive target to combat both neurodegenerative disease pathogenesis and circadian rhythm dysfunction, and a pivotal role for neuroinflammation and stress has been established. This review summarizes the contributions of molecular clock dysfunction to neurodegenerative disease etiology, as well as the mechanisms by which neurodegenerative diseases affect the molecular clock.
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Affiliation(s)
- Bethany Carter
- Gamsby Laboratory, USF Health Byrd Alzheimer's Center and Research Institute, University of South Florida Health, Tampa, FL, United States
| | - Hannah S Justin
- Gamsby Laboratory, USF Health Byrd Alzheimer's Center and Research Institute, University of South Florida Health, Tampa, FL, United States
| | - Danielle Gulick
- Gamsby Laboratory, USF Health Byrd Alzheimer's Center and Research Institute, University of South Florida Health, Tampa, FL, United States.,Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Joshua J Gamsby
- Gamsby Laboratory, USF Health Byrd Alzheimer's Center and Research Institute, University of South Florida Health, Tampa, FL, United States.,Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
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22
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Abstract
It doesn’t take much to disrupt our sleep. Whilst we are aware of environmental factors that can disturb our circadian rhythms, the precise mechanisms that control molecular time cues have remained elusive. Beesley and co-workers demonstrate that diseases associated with cytoplasmic crowding affect the sleep-wake cycle. They also pinpoint a precise time-limiting step in the trafficking of the pacemaker protein PERIOD.
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