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Noordally ZB, Hindle MM, Martin SF, Seaton DD, Simpson TI, Le Bihan T, Millar AJ. A phospho-dawn of protein modification anticipates light onset in the picoeukaryote Ostreococcus tauri. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:5514-5531. [PMID: 37481465 PMCID: PMC10540734 DOI: 10.1093/jxb/erad290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 07/20/2023] [Indexed: 07/24/2023]
Abstract
Diel regulation of protein levels and protein modification had been less studied than transcript rhythms. Here, we compare transcriptome data under light-dark cycles with partial proteome and phosphoproteome data, assayed using shotgun MS, from the alga Ostreococcus tauri, the smallest free-living eukaryote. A total of 10% of quantified proteins but two-thirds of phosphoproteins were rhythmic. Mathematical modelling showed that light-stimulated protein synthesis can account for the observed clustering of protein peaks in the daytime. Prompted by night-peaking and apparently dark-stable proteins, we also tested cultures under prolonged darkness, where the proteome changed less than under the diel cycle. Among the dark-stable proteins were prasinophyte-specific sequences that were also reported to accumulate when O. tauri formed lipid droplets. In the phosphoproteome, 39% of rhythmic phospho-sites reached peak levels just before dawn. This anticipatory phosphorylation suggests that a clock-regulated phospho-dawn prepares green cells for daytime functions. Acid-directed and proline-directed protein phosphorylation sites were regulated in antiphase, implicating the clock-related casein kinases 1 and 2 in phase-specific regulation, alternating with the CMGC protein kinase family. Understanding the dynamic phosphoprotein network should be facilitated by the minimal kinome and proteome of O. tauri. The data are available from ProteomeXchange, with identifiers PXD001734, PXD001735, and PXD002909.
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Affiliation(s)
- Zeenat B Noordally
- SynthSys and School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Matthew M Hindle
- SynthSys and School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Sarah F Martin
- SynthSys and School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Daniel D Seaton
- SynthSys and School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - T Ian Simpson
- Institute for Adaptive and Neural Computation, School of Informatics, University of Edinburgh, Edinburgh EH8 9AB, UK
| | - Thierry Le Bihan
- SynthSys and School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Andrew J Millar
- SynthSys and School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
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2
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Lakin-Thomas P. The Case for the Target of Rapamycin Pathway as a Candidate Circadian Oscillator. Int J Mol Sci 2023; 24:13307. [PMID: 37686112 PMCID: PMC10488232 DOI: 10.3390/ijms241713307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 08/23/2023] [Accepted: 08/25/2023] [Indexed: 09/10/2023] Open
Abstract
The molecular mechanisms that drive circadian (24 h) rhythmicity have been investigated for many decades, but we still do not have a complete picture of eukaryotic circadian systems. Although the transcription/translation feedback loop (TTFL) model has been the primary focus of research, there are many examples of circadian rhythms that persist when TTFLs are not functioning, and we lack any good candidates for the non-TTFL oscillators driving these rhythms. In this hypothesis-driven review, the author brings together several lines of evidence pointing towards the Target of Rapamycin (TOR) signalling pathway as a good candidate for a non-TTFL oscillator. TOR is a ubiquitous regulator of metabolism in eukaryotes and recent focus in circadian research on connections between metabolism and rhythms makes TOR an attractive candidate oscillator. In this paper, the evidence for a role for TOR in regulating rhythmicity is reviewed, and the advantages of TOR as a potential oscillator are discussed. Evidence for extensive feedback regulation of TOR provides potential mechanisms for a TOR-driven oscillator. Comparison with ultradian yeast metabolic cycles provides an example of a potential TOR-driven self-sustained oscillation. Unanswered questions and problems to be addressed by future research are discussed.
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3
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Li W, Wang Z, Cao J, Dong Y, Chen Y. Perfecting the Life Clock: The Journey from PTO to TTFL. Int J Mol Sci 2023; 24:ijms24032402. [PMID: 36768725 PMCID: PMC9916482 DOI: 10.3390/ijms24032402] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 01/20/2023] [Accepted: 01/21/2023] [Indexed: 01/27/2023] Open
Abstract
The ubiquity of biological rhythms in life implies that it results from selection in the evolutionary process. The origin of the biological clock has two possible hypotheses: the selective pressure hypothesis of the oxidative stress cycle and the light evasion hypothesis. Moreover, the biological clock gives life higher adaptability. Two biological clock mechanisms have been discovered: the negative feedback loop of transcription-translation (TTFL) and the post-translational oscillation mechanism (PTO). The TTFL mechanism is the most classic and relatively conservative circadian clock oscillation mechanism, commonly found in eukaryotes. We have introduced the TTFL mechanism of the classical model organisms. However, the biological clock of prokaryotes is based on the PTO mechanism. The Peroxiredoxin (PRX or PRDX) protein-based PTO mechanism circadian clock widely existing in eukaryotic and prokaryotic life is considered a more conservative oscillation mechanism. The coexistence of the PTO and TTFL mechanisms in eukaryotes prompted us to explain the relationship between the two. Finally, we speculated that there might be a driving force for the evolution of the biological clock. The biological clock may have an evolutionary trend from the PTO mechanism to the TTFL mechanism, resulting from the evolution of organisms adapting to the environment.
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Affiliation(s)
- Weitian Li
- College of Veterinary Medicine, China Agricultural University, Haidian, Beijing 100193, China
| | - Zixu Wang
- College of Veterinary Medicine, China Agricultural University, Haidian, Beijing 100193, China
| | - Jing Cao
- College of Veterinary Medicine, China Agricultural University, Haidian, Beijing 100193, China
| | - Yulan Dong
- College of Veterinary Medicine, China Agricultural University, Haidian, Beijing 100193, China
| | - Yaoxing Chen
- College of Veterinary Medicine, China Agricultural University, Haidian, Beijing 100193, China
- Department of Nutrition and Health, China Agricultural University, Haidian, Beijing 100193, China
- Correspondence: ; Tel.: +86-10-62733778
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Alexandre Moraes T, Mengin V, Peixoto B, Encke B, Krohn N, Höhne M, Krause U, Stitt M. The circadian clock mutant lhy cca1 elf3 paces starch mobilization to dawn despite severely disrupted circadian clock function. PLANT PHYSIOLOGY 2022; 189:2332-2356. [PMID: 35567528 PMCID: PMC9348821 DOI: 10.1093/plphys/kiac226] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 04/22/2022] [Indexed: 06/15/2023]
Abstract
Many plants, including Arabidopsis (Arabidopsis thaliana), accumulate starch in the daytime and remobilize it to support maintenance and growth at night. Starch accumulation is increased when carbon is in short supply, for example, in short photoperiods. Mobilization is paced to exhaust starch around dawn, as anticipated by the circadian clock. This diel pattern of turnover is largely robust against loss of day, dawn, dusk, or evening clock components. Here, we investigated diel starch turnover in the triple circadian clock mutant lhy cca1 elf3, which lacks the LATE ELONGATED HYPOCOTYL and the CIRCADIAN CLOCK-ASSOCIATED1 (CCA1) dawn components and the EARLY FLOWERING3 (ELF3) evening components of the circadian clock. The diel oscillations of transcripts for the remaining clock components and related genes like REVEILLE and PHYTOCHROME-INTERACING FACTOR family members exhibited attenuated amplitudes and altered peak time, weakened dawn dominance, and decreased robustness against changes in the external light-dark cycle. The triple mutant was unable to increase starch accumulation in short photoperiods. However, it was still able to pace starch mobilization to around dawn in different photoperiods and growth irradiances and to around 24 h after the previous dawn in T17 and T28 cycles. The triple mutant was able to slow down starch mobilization after a sudden low-light day or a sudden early dusk, although in the latter case it did not fully compensate for the lengthened night. Overall, there was a slight trend to less linear mobilization of starch. Thus, starch mobilization can be paced rather robustly to dawn despite a major disruption of the transcriptional clock. It is proposed that temporal information can be delivered from clock components or a semi-autonomous oscillator.
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Affiliation(s)
| | - Virginie Mengin
- School of Life Sciences, University of Essex, Colchester CO4 3SQ, UK
| | - Bruno Peixoto
- Instituto Gulbenkian de Ciência, Oeiras 2780-156,Portugal
- GREEN-IT Bioresources for Sustainability, ITQB NOVA, Oeiras 2780-157,Portugal
| | - Beatrice Encke
- Systematic Botany and Biodiversity, Humboldt University of Berlin, Berlin D-10115, Germany
| | - Nicole Krohn
- Abteilung für Parodontologie und Synoptische Zahnmedizin, Charité Universitätsmedizin, Berlin 14197, Germany
| | - Melanie Höhne
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany
| | - Ursula Krause
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany
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5
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Kay H, Taylor H, van Ooijen G. Environmental and Circadian Regulation Combine to Shape the Rhythmic Selenoproteome. Cells 2022; 11:cells11030340. [PMID: 35159150 PMCID: PMC8834552 DOI: 10.3390/cells11030340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/13/2022] [Accepted: 01/18/2022] [Indexed: 02/01/2023] Open
Abstract
The circadian clock orchestrates an organism’s endogenous processes with environmental 24 h cycles. Redox homeostasis and the circadian clock regulate one another to negate the potential effects of our planet’s light/dark cycle on the generation of reactive oxygen species (ROS) and attain homeostasis. Selenoproteins are an important class of redox-related enzymes that have a selenocysteine residue in the active site. This study reports functional understanding of how environmental and endogenous circadian rhythms integrate to shape the selenoproteome in a model eukaryotic cell. We mined quantitative proteomic data for the 24 selenoproteins of the picoeukaryote Ostreococcus tauri across time series, under environmentally rhythmic entrained conditions of light/dark (LD) cycles, compared to constant circadian conditions of constant light (LL). We found an overrepresentation of selenoproteins among rhythmic proteins under LL, but an underrepresentation under LD conditions. Rhythmic selenoproteins under LL that reach peak abundance later in the day showed a greater relative amplitude of oscillations than those that peak early in the day. Under LD, amplitude did not correlate with peak phase; however, we identified high-amplitude selenium uptake rhythms under LD but not LL conditions. Selenium deprivation induced strong qualitative defects in clock gene expression under LD but not LL conditions. Overall, the clear conclusion is that the circadian and environmental cycles exert differential effects on the selenoproteome, and that the combination of the two enables homeostasis. Selenoproteins may therefore play an important role in the cellular response to reactive oxygen species that form as a consequence of the transitions between light and dark.
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6
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Olekhnovich EI, Batotsyrenova EG, Yunes RA, Kashuro VA, Poluektova EU, Veselovsky VA, Ilina EN, Danilenko VN, Klimina KM. The effects of Levilactobacillus brevis on the physiological parameters and gut microbiota composition of rats subjected to desynchronosis. Microb Cell Fact 2021; 20:226. [PMID: 34930242 PMCID: PMC8686522 DOI: 10.1186/s12934-021-01716-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 12/02/2021] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND All living organisms have developed during evolution complex time-keeping biological clocks that allowed them to stay attuned to their environments. Circadian rhythms cycle on a near 24 h clock. These encompass a variety of changes in the body ranging from blood hormone levels to metabolism, to the gut microbiota composition and others. The gut microbiota, in return, influences the host stress response and the physiological changes associated with it, which makes it an important determinant of health. Lactobacilli are traditionally consumed for their prophylactic and therapeutic benefits against various diseases, namely, the inflammatory bowel syndrome, and even emerged recently as promising psychobiotics. However, the potential role of lactobacilli in the normalization of circadian rhythms has not been addressed. RESULTS Two-month-old male rats were randomly divided into three groups and housed under three different light/dark cycles for three months: natural light, constant light and constant darkness. The strain Levilactobacillus brevis 47f was administered to rats at a dose of 0.5 ml per rat for one month and The rats were observed for the following two months. As a result, we identified the biomarkers associated with intake of L. brevis 47f. Changing the light regime for three months depleted the reserves of the main buffer in the cell-reduced glutathione. Intake of L. brevis 47f for 30 days restored cellular reserves of reduced glutathione and promoted redox balance. Our results indicate that the levels of urinary catecholamines correlated with light/dark cycles and were influenced by intake of L. brevis 47f. The gut microbiota of rats was also influenced by these factors. L. brevis 47f intake was associated with an increase in the relative abundance of Faecalibacterium and Roseburia and a decrease in the relative abundance of Prevotella and Bacteroides. CONCLUSIONS The results of this study show that oral administration of L. brevis 47f, for one month, to rats housed under abnormal lightning conditions (constant light or constant darkness) normalized their physiological parameters and promoted the gut microbiome's balance.
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Affiliation(s)
- Evgenii I. Olekhnovich
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, 119435 Russia
| | - Ekaterina G. Batotsyrenova
- Saint Petersburg State Pediatric Medical University, 2 Litovskaya str., St. Petersburg, 194100 Russia
- Golikov Research Center of Toxicology Under Federal Medical Biological Agency, 1 Bekhtereva str., St. Petersburg, 192019 Russia
| | - Roman A. Yunes
- Department of Genetics and Biotechnology, Vavilov Institute of General Genetics Russian Academy of Sciences, Moscow, 119991 Russia
| | - Vadim A. Kashuro
- Saint Petersburg State Pediatric Medical University, 2 Litovskaya str., St. Petersburg, 194100 Russia
- Golikov Research Center of Toxicology Under Federal Medical Biological Agency, 1 Bekhtereva str., St. Petersburg, 192019 Russia
| | - Elena U. Poluektova
- Department of Genetics and Biotechnology, Vavilov Institute of General Genetics Russian Academy of Sciences, Moscow, 119991 Russia
| | - Vladimir A. Veselovsky
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, 119435 Russia
| | - Elena N. Ilina
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, 119435 Russia
| | - Valeriy N. Danilenko
- Department of Genetics and Biotechnology, Vavilov Institute of General Genetics Russian Academy of Sciences, Moscow, 119991 Russia
| | - Ksenia M. Klimina
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, 119435 Russia
- Department of Genetics and Biotechnology, Vavilov Institute of General Genetics Russian Academy of Sciences, Moscow, 119991 Russia
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7
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Krahmer J, Hindle M, Perby LK, Mogensen HK, Nielsen TH, Halliday KJ, VanOoijen G, LeBihan T, Millar AJ. The circadian clock gene circuit controls protein and phosphoprotein rhythms in Arabidopsis thaliana. Mol Cell Proteomics 2021; 21:100172. [PMID: 34740825 PMCID: PMC8733343 DOI: 10.1016/j.mcpro.2021.100172] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 09/27/2021] [Accepted: 11/01/2021] [Indexed: 11/29/2022] Open
Abstract
Twenty-four-hour, circadian rhythms control many eukaryotic mRNA levels, whereas the levels of their more stable proteins are not expected to reflect the RNA rhythms, emphasizing the need to test the circadian regulation of protein abundance and modification. Here we present circadian proteomic and phosphoproteomic time series from Arabidopsis thaliana plants under constant light conditions, estimating that just 0.4% of quantified proteins but a much larger proportion of quantified phospho-sites were rhythmic. Approximately half of the rhythmic phospho-sites were most phosphorylated at subjective dawn, a pattern we term the “phospho-dawn.” Members of the SnRK/CDPK family of protein kinases are candidate regulators. A CCA1-overexpressing line that disables the clock gene circuit lacked most circadian protein phosphorylation. However, the few phospho-sites that fluctuated despite CCA1-overexpression still tended to peak in abundance close to subjective dawn, suggesting that the canonical clock mechanism is necessary for most but perhaps not all protein phosphorylation rhythms. To test the potential functional relevance of our datasets, we conducted phosphomimetic experiments using the bifunctional enzyme fructose-6-phosphate-2-kinase/phosphatase (F2KP), as an example. The rhythmic phosphorylation of diverse protein targets is controlled by the clock gene circuit, implicating posttranslational mechanisms in the transmission of circadian timing information in plants. Circadian (phospho)proteomics time courses of plants with or without functional clock. Most protein abundance/phosphorylation rhythms require a transcriptional oscillator. The majority of rhythmic phosphosites peak around subjective dawn (“phospho-dawn”). A phosphorylated serine of the metabolic enzyme F2KP has functional relevance.
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Affiliation(s)
- Johanna Krahmer
- SynthSys and School of Biological Sciences, CH Waddington Building, Max Born Crescent, Kings Buildings, University of Edinburgh, Edinburgh, EH9 3BF, United Kingdom; Institute for Molecular Plant Science, School of Biological Sciences, Daniel Rutherford Building, Building, Max Born Crescent, Kings Buildings, University of Edinburgh, Edinburgh, EH9 3BF, United Kingdom.
| | - Matthew Hindle
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, Easter Bush, Edinburgh, EH25 9RG, United Kingdom
| | - Laura K Perby
- Department of Plant and Environmental Sciences, University of Copenhagen, Section for Molecular Plant Biology, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
| | - Helle K Mogensen
- Department of Plant and Environmental Sciences, University of Copenhagen, Section for Molecular Plant Biology, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
| | - Tom H Nielsen
- Department of Plant and Environmental Sciences, University of Copenhagen, Section for Molecular Plant Biology, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
| | - Karen J Halliday
- Institute for Molecular Plant Science, School of Biological Sciences, Daniel Rutherford Building, Building, Max Born Crescent, Kings Buildings, University of Edinburgh, Edinburgh, EH9 3BF, United Kingdom
| | - Gerben VanOoijen
- Institute for Molecular Plant Science, School of Biological Sciences, Daniel Rutherford Building, Building, Max Born Crescent, Kings Buildings, University of Edinburgh, Edinburgh, EH9 3BF, United Kingdom
| | - Thierry LeBihan
- SynthSys and School of Biological Sciences, CH Waddington Building, Max Born Crescent, Kings Buildings, University of Edinburgh, Edinburgh, EH9 3BF, United Kingdom
| | - Andrew J Millar
- SynthSys and School of Biological Sciences, CH Waddington Building, Max Born Crescent, Kings Buildings, University of Edinburgh, Edinburgh, EH9 3BF, United Kingdom.
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8
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Kay H, Grünewald E, Feord HK, Gil S, Peak-Chew SY, Stangherlin A, O'Neill JS, van Ooijen G. Deep-coverage spatiotemporal proteome of the picoeukaryote Ostreococcus tauri reveals differential effects of environmental and endogenous 24-hour rhythms. Commun Biol 2021; 4:1147. [PMID: 34593975 PMCID: PMC8484446 DOI: 10.1038/s42003-021-02680-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 09/07/2021] [Indexed: 11/18/2022] Open
Abstract
The cellular landscape changes dramatically over the course of a 24 h day. The proteome responds directly to daily environmental cycles and is additionally regulated by the circadian clock. To quantify the relative contribution of diurnal versus circadian regulation, we mapped proteome dynamics under light:dark cycles compared with constant light. Using Ostreococcus tauri, a prototypical eukaryotic cell, we achieved 85% coverage, which allowed an unprecedented insight into the identity of proteins that facilitate rhythmic cellular functions. The overlap between diurnally- and circadian-regulated proteins was modest and these proteins exhibited different phases of oscillation between the two conditions. Transcript oscillations were generally poorly predictive of protein oscillations, in which a far lower relative amplitude was observed. We observed coordination between the rhythmic regulation of organelle-encoded proteins with the nuclear-encoded proteins that are targeted to organelles. Rhythmic transmembrane proteins showed a different phase distribution compared with rhythmic soluble proteins, indicating the existence of a circadian regulatory process specific to the biogenesis and/or degradation of membrane proteins. Our observations argue that the cellular spatiotemporal proteome is shaped by a complex interaction between intrinsic and extrinsic regulatory factors through rhythmic regulation at the transcriptional as well as post-transcriptional, translational, and post-translational levels. Holly Kay, Ellen Grünewald, et al. provide an in-depth examination of the proteome in the eukaryotic green alga, Ostreococcus tauri, under circadian constant light or cycling diurnal light-dark conditions. They observe that there is little overlap between mRNA and protein expression rhythms, or the diurnal and circadian proteome, suggesting that the cellular spatiotemporal proteome is shaped through rhythmic regulation at multiple stages of transcription and translation.
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Affiliation(s)
- Holly Kay
- School of Biological Sciences, University of Edinburgh, Max Born Crescent, Edinburgh, EH9 3BF, UK
| | - Ellen Grünewald
- School of Biological Sciences, University of Edinburgh, Max Born Crescent, Edinburgh, EH9 3BF, UK
| | - Helen K Feord
- School of Biological Sciences, University of Edinburgh, Max Born Crescent, Edinburgh, EH9 3BF, UK
| | - Sergio Gil
- School of Biological Sciences, University of Edinburgh, Max Born Crescent, Edinburgh, EH9 3BF, UK
| | - Sew Y Peak-Chew
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | | | - John S O'Neill
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Gerben van Ooijen
- School of Biological Sciences, University of Edinburgh, Max Born Crescent, Edinburgh, EH9 3BF, UK.
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9
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Eskandari R, Ratnayake L, Lakin-Thomas PL. Shared Components of the FRQ-Less Oscillator and TOR Pathway Maintain Rhythmicity in Neurospora. J Biol Rhythms 2021; 36:329-345. [PMID: 33825541 PMCID: PMC8276340 DOI: 10.1177/0748730421999948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Molecular models for the endogenous oscillators that drive circadian rhythms in eukaryotes center on rhythmic transcription/translation of a small number of "clock genes." Although substantial evidence supports the concept that negative and positive transcription/translation feedback loops (TTFLs) are responsible for regulating the expression of these clock genes, certain rhythms in the filamentous fungus Neurospora crassa continue even when clock genes (frq, wc-1, and wc-2) are not rhythmically expressed. Identification of the rhythmic processes operating outside of the TTFL has been a major unresolved area in circadian biology. Our lab previously identified a mutation (vta) that abolishes FRQ-less rhythmicity of the conidiation rhythm and also affects rhythmicity when FRQ is functional. Further studies identified the vta gene product as a component of the TOR (Target of Rapamycin) nutrient-sensing pathway that is conserved in eukaryotes. We now report the discovery of TOR pathway components including GTR2 (homologous to the yeast protein Gtr2, and RAG C/D in mammals) as binding partners of VTA through co-immunoprecipitation (IP) and mass spectrometry analysis using a VTA-FLAG strain. Reciprocal IP with GTR2-FLAG found VTA as a binding partner. A Δgtr2 strain was deficient in growth responses to amino acids. Free-running conidiation rhythms in a FRQ-less strain were abolished in Δgtr2. Entrainment of a FRQ-less strain to cycles of heat pulses demonstrated that Δgtr2 is defective in entrainment. In all of these assays, Δgtr2 is similar to Δvta. In addition, expression of GTR2 protein was found to be rhythmic across two circadian cycles, and functional VTA was required for GTR2 rhythmicity. FRQ protein exhibited the expected rhythm in the presence of GTR2 but the rhythmic level of FRQ dampened in the absence of GTR2. These results establish association of VTA with GTR2, and their role in maintaining functional circadian rhythms through the TOR pathway.
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Affiliation(s)
- Rosa Eskandari
- Department of Biology, York University, Toronto, ON, Canada
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10
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Fitzpatrick TB, Noordally Z. Of clocks and coenzymes in plants: intimately connected cycles guiding central metabolism? THE NEW PHYTOLOGIST 2021; 230:416-432. [PMID: 33264424 DOI: 10.1111/nph.17127] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 11/03/2020] [Indexed: 06/12/2023]
Abstract
Plant fitness is a measure of the capacity of a plant to survive and reproduce in its particular environment. It is inherently dependent on plant health. Molecular timekeepers like the circadian clock enhance fitness due to their ability to coordinate biochemical and physiological processes with the environment on a daily basis. Central metabolism underlies these events and it is well established that diel metabolite adjustments are intimately and reciprocally associated with the genetically encoded clock. Thus, metabolic pathway activities are time-of-day regulated. Metabolite rhythms are driven by enzymes, a major proportion of which rely on organic coenzymes to facilitate catalysis. The B vitamin complex is the key provider of coenzymes in all organisms. Emerging evidence suggests that B vitamin levels themselves undergo daily oscillations in animals but has not been studied in any depth in plants. Moreover, it is rarely considered that daily rhythmicity in coenzyme levels may dictate enzyme activity levels and therefore metabolite levels. Here we put forward the proposal that B-vitamin-derived coenzyme rhythmicity is intertwined with metabolic and clock derived rhythmicity to achieve a tripartite homeostasis integrated into plant fitness.
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Affiliation(s)
- Teresa B Fitzpatrick
- Vitamins and Environmental Stress Responses in Plants, Department of Botany and Plant Biology, University of Geneva, Geneva, 1211, Switzerland
| | - Zeenat Noordally
- Vitamins and Environmental Stress Responses in Plants, Department of Botany and Plant Biology, University of Geneva, Geneva, 1211, Switzerland
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11
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The recovery of KaiA’s activity depends on its N-terminal domain and KaiB in the cyanobacterial circadian clock. Biochem Biophys Res Commun 2020; 524:123-128. [DOI: 10.1016/j.bbrc.2020.01.072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 01/13/2020] [Indexed: 11/20/2022]
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12
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Feord HK, Dear FEG, Obbard DJ, van Ooijen G. A Magnesium Transport Protein Related to Mammalian SLC41 and Bacterial MgtE Contributes to Circadian Timekeeping in a Unicellular Green Alga. Genes (Basel) 2019; 10:genes10020158. [PMID: 30791470 PMCID: PMC6410215 DOI: 10.3390/genes10020158] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 01/29/2019] [Accepted: 02/12/2019] [Indexed: 11/16/2022] Open
Abstract
Circadian clocks in eukaryotes involve both transcriptional-translational feedback loops, post-translational regulation, and metabolic, non-transcriptional oscillations. We recently identified the involvement of circadian oscillations in the intracellular concentrations of magnesium ions (Mg2+i) that were conserved in three eukaryotic kingdoms. Mg2+i in turn contributes to transcriptional clock properties of period and amplitude, and can function as a zeitgeber to define phase. However, the mechanism-or mechanisms-responsible for the generation of Mg2+i oscillations, and whether these are functionally conserved across taxonomic groups, remain elusive. We employed the cellular clock model Ostreococcustauri to provide a first study of an MgtE domain-containing protein in the green lineage. OtMgtE shares homology with the mammalian SLC41A1 magnesium/sodium antiporter, which has previously been implicated in maintaining clock period. Using genetic overexpression, we found that OtMgtE contributes to both timekeeping and daily changes in Mg2+i. However, pharmacological experiments and protein sequence analyses indicated that critical differences exist between OtMgtE and either the ancestral MgtE channel or the mammalian SLC41 antiporters. We concluded that even though MgtE domain-containing proteins are only distantly related, these proteins retain a shared role in contributing to cellular timekeeping and the regulation of Mg2+i.
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Affiliation(s)
- Helen K Feord
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK.
| | - Frederick E G Dear
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK.
| | - Darren J Obbard
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK.
| | - Gerben van Ooijen
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK.
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13
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Circadian rhythms, metabolic oscillators, and the target of rapamycin (TOR) pathway: the Neurospora connection. Curr Genet 2018; 65:339-349. [DOI: 10.1007/s00294-018-0897-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 10/09/2018] [Accepted: 10/20/2018] [Indexed: 01/25/2023]
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14
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Ode KL, Ueda HR. Design Principles of Phosphorylation-Dependent Timekeeping in Eukaryotic Circadian Clocks. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a028357. [PMID: 29038116 DOI: 10.1101/cshperspect.a028357] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The circadian clock in cyanobacteria employs a posttranslational oscillator composed of a sequential phosphorylation-dephosphorylation cycle of KaiC protein, in which the dynamics of protein structural changes driven by temperature-compensated KaiC's ATPase activity are critical for determining the period. On the other hand, circadian clocks in eukaryotes employ transcriptional feedback loops as a core mechanism. In this system, the dynamics of protein accumulation and degradation affect the circadian period. However, recent studies of eukaryotic circadian clocks reveal that the mechanism controlling the circadian period can be independent of the regulation of protein abundance. Instead, the circadian substrate is often phosphorylated at multiple sites at flexible protein regions to induce structural changes. The phosphorylation is catalyzed by kinases that induce sequential multisite phosphorylation such as casein kinase 1 (CK1) with temperature-compensated activity. We propose that the design principles of phosphorylation-dependent circadian-period determination in eukaryotes may share characteristics with the posttranslational oscillator in cyanobacteria.
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Affiliation(s)
- Koji L Ode
- Department of Systems Pharmacology, Graduate School of Medicine, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.,Laboratory for Synthetic Biology, RIKEN Quantitative Biology Center, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Hiroki R Ueda
- Department of Systems Pharmacology, Graduate School of Medicine, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.,Laboratory for Synthetic Biology, RIKEN Quantitative Biology Center, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
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15
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Ratnayake L, Adhvaryu KK, Kafes E, Motavaze K, Lakin-Thomas P. A component of the TOR (Target Of Rapamycin) nutrient-sensing pathway plays a role in circadian rhythmicity in Neurospora crassa. PLoS Genet 2018; 14:e1007457. [PMID: 29924817 PMCID: PMC6028147 DOI: 10.1371/journal.pgen.1007457] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 07/02/2018] [Accepted: 05/31/2018] [Indexed: 01/06/2023] Open
Abstract
The TOR (Target of Rapamycin) pathway is a highly-conserved signaling pathway in eukaryotes that regulates cellular growth and stress responses. The cellular response to amino acids or carbon sources such as glucose requires anchoring of the TOR kinase complex to the lysosomal/vacuolar membrane by the Ragulator (mammals) or EGO (yeast) protein complex. Here we report a connection between the TOR pathway and circadian (daily) rhythmicity. The molecular mechanism of circadian rhythmicity in all eukaryotes has long been thought to be transcription/translation feedback loops (TTFLs). In the model eukaryote Neurospora crassa, a TTFL including FRQ (frequency) and WCC (white collar complex) has been intensively studied. However, it is also well-known that rhythmicity can be seen in the absence of TTFL functioning. We previously isolated uv90 as a mutation that compromises FRQ-less rhythms and also damps the circadian oscillator when FRQ is present. We have now mapped the uv90 gene and identified it as NCU05950, homologous to the TOR pathway proteins EGO1 (yeast) and LAMTOR1 (mammals), and we have named the N. crassa protein VTA (vacuolar TOR-associated protein). The protein is anchored to the outer vacuolar membrane and deletion of putative acylation sites destroys this localization as well as the protein’s function in rhythmicity. A deletion of VTA is compromised in its growth responses to amino acids and glucose. We conclude that a key protein in the complex that anchors TOR to the vacuole plays a role in maintaining circadian (daily) rhythmicity. Our results establish a connection between the TOR pathway and circadian rhythms and point towards a network integrating metabolism and the circadian system. Circadian clocks drive 24-hour rhythms in living things at all levels of organization, from single cells to whole organisms. In spite of the importance of daily clocks for organizing the activities and internal functions of organisms, there are still many unsolved problems concerning the molecular mechanisms. In eukaryotes, a set of “clock proteins” turns on and off specific genes in a 24-hour feedback loop. This “clock gene feedback loop” has been the dominant idea about how clocks work for many years. However, some rhythms can still be seen when these feedback loops are not functioning. Using the fungus Neurospora crassa as a model organism, we have discovered a gene that is important for maintaining rhythms that continue without the known feedback loop. We have found that this gene codes for a protein that was already known to be important in helping cells to adjust their growth rate to adapt to varying availability of nutrients. Because the same gene is found in all eukaryotes, including mammals, this finding may point towards a universal clock mechanism that integrates nutritional needs with daily rhythms.
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16
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Abstract
Mounting evidence in recent years supports the extensive interaction between the circadian and redox systems. The existence of such a relationship is not surprising because most organisms, be they diurnal or nocturnal, display daily oscillations in energy intake, locomotor activity, and exposure to exogenous and internally generated oxidants. The transcriptional clock controls the levels of many antioxidant proteins and redox-active cofactors, and, conversely, the cellular redox poise has been shown to feed back to the transcriptional oscillator via redox-sensitive transcription factors and enzymes. However, the circadian cycles in the S-sulfinylation of the peroxiredoxin (PRDX) proteins constituted the first example of an autonomous circadian redox oscillation, which occurred independently of the transcriptional clock. Importantly, the high phylogenetic conservation of these rhythms suggests that they might predate the evolution of the transcriptional oscillator, and therefore could be a part of a primordial circadian redox/metabolic oscillator. This discovery forced the reappraisal of the dogmatic transcription-centered view of the clockwork and opened a new avenue of research. Indeed, the investigation into the links between the circadian and redox systems is still in its infancy, and many important questions remain to be addressed.
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17
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Kinoshita C, Aoyama K, Nakaki T. Neuroprotection afforded by circadian regulation of intracellular glutathione levels: A key role for miRNAs. Free Radic Biol Med 2018; 119:17-33. [PMID: 29198727 DOI: 10.1016/j.freeradbiomed.2017.11.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 11/21/2017] [Accepted: 11/27/2017] [Indexed: 01/17/2023]
Abstract
Circadian rhythms are approximately 24-h oscillations of physiological and behavioral processes that allow us to adapt to daily environmental cycles. Like many other biological functions, cellular redox status and antioxidative defense systems display circadian rhythmicity. In the central nervous system (CNS), glutathione (GSH) is a critical antioxidant because the CNS is extremely vulnerable to oxidative stress; oxidative stress, in turn, causes several fatal diseases, including neurodegenerative diseases. It has long been known that GSH level shows circadian rhythm, although the mechanism underlying GSH rhythm production has not been well-studied. Several lines of recent evidence indicate that the expression of antioxidant genes involved in GSH homeostasis as well as circadian clock genes are regulated by post-transcriptional regulator microRNA (miRNA), indicating that miRNA plays a key role in generating GSH rhythm. Interestingly, several reports have shown that alterations of miRNA expression as well as circadian rhythm have been known to link with various diseases related to oxidative stress. A growing body of evidence implicates a strong correlation between antioxidative defense, circadian rhythm and miRNA function, therefore, their dysfunctions could cause numerous diseases. It is hoped that continued elucidation of the antioxidative defense systems controlled by novel miRNA regulation under circadian control will advance the development of therapeutics for the diseases caused by oxidative stress.
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Affiliation(s)
- Chisato Kinoshita
- Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Koji Aoyama
- Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Toshio Nakaki
- Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan.
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18
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The putative role of oxidative stress and inflammation in the pathophysiology of sleep dysfunction across neuropsychiatric disorders: Focus on chronic fatigue syndrome, bipolar disorder and multiple sclerosis. Sleep Med Rev 2018; 41:255-265. [PMID: 29759891 DOI: 10.1016/j.smrv.2018.03.007] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 02/20/2018] [Accepted: 03/27/2018] [Indexed: 12/29/2022]
Abstract
Sleep and circadian abnormalities are prevalent and burdensome manifestations of diverse neuro-immune diseases, and may aggravate the course of several neuropsychiatric disorders. The underlying pathophysiology of sleep abnormalities across neuropsychiatric disorders remains unclear, and may involve the inter-play of several clinical variables and mechanistic pathways. In this review, we propose a heuristic framework in which reciprocal interactions of immune, oxidative and nitrosative stress, and mitochondrial pathways may drive sleep abnormalities across potentially neuroprogressive disorders. Specifically, it is proposed that systemic inflammation may activate microglial cells and astrocytes in brain regions involved in sleep and circadian regulation. Activated glial cells may secrete pro-inflammatory cytokines (for example, interleukin-1 beta and tumour necrosis factor alpha), nitric oxide and gliotransmitters, which may influence the expression of key circadian regulators (e.g., the Circadian Locomotor Output Cycles Kaput (CLOCK) gene). Furthermore, sleep disruption may further aggravate oxidative and nitrosative, peripheral immune activation, and (neuro) inflammation across these disorders in a vicious pathophysiological loop. This review will focus on chronic fatigue syndrome, bipolar disorder, and multiple sclerosis as exemplars of neuro-immune disorders. We conclude that novel therapeutic targets exploring immune and oxidative & nitrosative pathways (p.e. melatonin and molecular hydrogen) hold promise in alleviating sleep and circadian dysfunction in these disorders.
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19
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Hansen LL, van den Burg HA, van Ooijen G. Sumoylation Contributes to Timekeeping and Temperature Compensation of the Plant Circadian Clock. J Biol Rhythms 2017; 32:560-569. [PMID: 29172926 DOI: 10.1177/0748730417737633] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The transcriptional circadian clock network is tuned into a 24-h oscillator by numerous posttranslational modifications on the proteins encoded by clock genes, differentially influencing their subcellular localization or activity. Clock proteins in any circadian organism are subject to posttranslational regulation, and many of the key enzymes, notably kinases and phosphatases, are functionally conserved between the clocks of mammals, fungi, and plants. We now establish sumoylation, the posttranslational modification of target proteins by the covalent attachment of the small ubiquitin-like modifier protein SUMO, as a novel mechanism regulating key clock properties in the model plant Arabidopsis. Using 2 different approaches, we show that mutant plant lines with decreased or increased levels of global sumoylation exhibit shortened or lengthened circadian period, respectively. One known functional role of sumoylation is to protect the proteome from temperature stress. The circadian clock is characterized by temperature compensation, meaning that proper timekeeping is ensured over the full range of physiologically relevant temperatures. Interestingly, we observed that the period defects in sumoylation mutant plants are strongly differential across temperature. Increased global sumoylation leads to undercompensation of the clock against temperature and decreased sumoylation to overcompensation, implying that sumoylation buffers the plant clock system against differential ambient temperature.
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Affiliation(s)
- Louise L Hansen
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Harrold A van den Burg
- Molecular Plant Pathology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Gerben van Ooijen
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
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20
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Gloston GF, Yoo SH, Chen ZJ. Clock-Enhancing Small Molecules and Potential Applications in Chronic Diseases and Aging. Front Neurol 2017; 8:100. [PMID: 28360884 PMCID: PMC5350099 DOI: 10.3389/fneur.2017.00100] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Accepted: 02/28/2017] [Indexed: 12/31/2022] Open
Abstract
Normal physiological functions require a robust biological timer called the circadian clock. When clocks are dysregulated, misaligned, or dampened, pathological consequences ensue, leading to chronic diseases and accelerated aging. An emerging research area is the development of clock-targeting compounds that may serve as drug candidates to correct dysregulated rhythms and hence mitigate disease symptoms and age-related decline. In this review, we first present a concise view of the circadian oscillator, physiological networks, and regulatory mechanisms of circadian amplitude. Given a close association of circadian amplitude dampening and disease progression, clock-enhancing small molecules (CEMs) are of particular interest as candidate chronotherapeutics. A recent proof-of-principle study illustrated that the natural polymethoxylated flavonoid nobiletin directly targets the circadian oscillator and elicits robust metabolic improvements in mice. We describe mood disorders and aging as potential therapeutic targets of CEMs. Future studies of CEMs will shed important insight into the regulation and disease relevance of circadian clocks.
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Affiliation(s)
- Gabrielle F Gloston
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston , Houston, TX , USA
| | - Seung-Hee Yoo
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston , Houston, TX , USA
| | - Zheng Jake Chen
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston , Houston, TX , USA
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21
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Otsuka K, Cornelissen G, Furukawa S, Kubo Y, Hayashi M, Shibata K, Mizuno K, Aiba T, Ohshima H, Mukai C. Long-term exposure to space's microgravity alters the time structure of heart rate variability of astronauts. Heliyon 2016; 2:e00211. [PMID: 28050606 PMCID: PMC5192238 DOI: 10.1016/j.heliyon.2016.e00211] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 11/21/2016] [Accepted: 12/05/2016] [Indexed: 01/20/2023] Open
Abstract
Background Spaceflight alters human cardiovascular dynamics. The less negative slope of the fractal scaling of heart rate variability (HRV) of astronauts exposed long-term to microgravity reflects cardiovascular deconditioning. We here focus on specific frequency regions of HRV. Methods Ten healthy astronauts (8 men, 49.1 ± 4.2 years) provided five 24-hour electrocardiographic (ECG) records: before launch, 20.8 ± 2.9 (ISS01), 72.5 ± 3.9 (ISS02) and 152.8 ± 16.1 (ISS03) days after launch, and after return to Earth. HRV endpoints, determined from normal-to-normal (NN) intervals in 180-min intervals progressively displaced by 5 min, were compared in space versus Earth. They were fitted with a model including 4 major anticipated components with periods of 24 (circadian), 12 (circasemidian), 8 (circaoctohoran), and 1.5 (Basic Rest-Activity Cycle; BRAC) hours. Findings The 24-, 12-, and 8-hour components of HRV persisted during long-term spaceflight. The 90-min amplitude became about three times larger in space (ISS03) than on Earth, notably in a subgroup of 7 astronauts who presented with a different HRV profile before flight. The total spectral power (TF; p < 0.05) and that in the ultra-low frequency range (ULF, 0.0001–0.003 Hz; p < 0.01) increased from 154.9 ± 105.0 and 117.9 ± 57.5 msec2 (before flight) to 532.7 ± 301.3 and 442.4 ± 202.9 msec2 (ISS03), respectively. The power-law fractal scaling β was altered in space, changing from -1.087 ± 0.130 (before flight) to -0.977 ± 0.098 (ISS01), -0.910 ± 0.130 (ISS02), and -0.924 ± 0.095 (ISS03) (invariably p < 0.05). Interpretation Most HRV changes observed in space relate to a frequency window centered around one cycle in about 90 min. Since the BRAC component is amplified in space for only specific HRV endpoints, it is likely to represent a physiologic response rather than an artifact from the International Space Station (ISS) orbit. If so, it may offer a way to help adaptation to microgravity during long-duration spaceflight.
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Affiliation(s)
- Kuniaki Otsuka
- Executive Medical Center, Totsuka Royal Clinic, Tokyo Women's Medical University, Tokyo, Japan; Halberg Chronobiology Center, University of Minnesota, Minneapolis, MN, USA
| | | | - Satoshi Furukawa
- Space Biomedical Research Group, Japan Aerospace Exploration Agency, Tokyo, Japan
| | - Yutaka Kubo
- Department of Medicine, Tokyo Women's Medical University, Medical Center East, Tokyo, Japan
| | - Mitsutoshi Hayashi
- Department of Medicine, Tokyo Women's Medical University, Medical Center East, Tokyo, Japan
| | - Koichi Shibata
- Department of Medicine, Tokyo Women's Medical University, Medical Center East, Tokyo, Japan
| | - Koh Mizuno
- Space Biomedical Research Group, Japan Aerospace Exploration Agency, Tokyo, Japan; Faculty of Child and Family Studies, Tohoku Fukushi University, Miyagi, Japan
| | - Tatsuya Aiba
- Space Biomedical Research Group, Japan Aerospace Exploration Agency, Tokyo, Japan; Ministry of Education, Culture, Sports, Science and Technology, Tokyo, Japan
| | - Hiroshi Ohshima
- Space Biomedical Research Group, Japan Aerospace Exploration Agency, Tokyo, Japan
| | - Chiaki Mukai
- Space Biomedical Research Group, Japan Aerospace Exploration Agency, Tokyo, Japan
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22
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Delis C, Krokida A, Tomatsidou A, Tsikou D, Beta RAA, Tsioumpekou M, Moustaka J, Stravodimos G, Leonidas DD, Balatsos NAA, Papadopoulou KK. AtHESPERIN: a novel regulator of circadian rhythms with poly(A)-degrading activity in plants. RNA Biol 2016; 13:68-82. [PMID: 26619288 DOI: 10.1080/15476286.2015.1119363] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
We report the identification and characterization of a novel gene, AtHesperin (AtHESP) that codes for a deadenylase in Arabidopsis thaliana. The gene is under circadian clock-gene regulation and has similarity to the mammalian Nocturnin. AtHESP can efficiently degrade poly(A) substrates exhibiting allosteric kinetics. Size exclusion chromatography and native electrophoresis coupled with kinetic analysis support that the native enzyme is oligomeric with at least 3 binding sites. Knockdown and overexpression of AtHESP in plant lines affects the expression and rhythmicity of the clock core oscillator genes TOC1 and CCA1. This study demonstrates an evolutionary conserved poly(A)-degrading activity in plants and suggests deadenylation as a mechanism involved in the regulation of the circadian clock. A role of AtHESP in stress response in plants is also depicted.
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Affiliation(s)
- Costas Delis
- a Department of Biochemistry and Biotechnology , University of Thessaly , Larissa , 412 21 , Greece
| | - Afrodite Krokida
- a Department of Biochemistry and Biotechnology , University of Thessaly , Larissa , 412 21 , Greece
| | - Anastasia Tomatsidou
- a Department of Biochemistry and Biotechnology , University of Thessaly , Larissa , 412 21 , Greece
| | - Daniela Tsikou
- a Department of Biochemistry and Biotechnology , University of Thessaly , Larissa , 412 21 , Greece
| | - Rafailia A A Beta
- a Department of Biochemistry and Biotechnology , University of Thessaly , Larissa , 412 21 , Greece
| | - Maria Tsioumpekou
- a Department of Biochemistry and Biotechnology , University of Thessaly , Larissa , 412 21 , Greece
| | - Julietta Moustaka
- a Department of Biochemistry and Biotechnology , University of Thessaly , Larissa , 412 21 , Greece
| | - Georgios Stravodimos
- a Department of Biochemistry and Biotechnology , University of Thessaly , Larissa , 412 21 , Greece
| | - Demetres D Leonidas
- a Department of Biochemistry and Biotechnology , University of Thessaly , Larissa , 412 21 , Greece
| | - Nikolaos A A Balatsos
- a Department of Biochemistry and Biotechnology , University of Thessaly , Larissa , 412 21 , Greece
| | - Kalliope K Papadopoulou
- a Department of Biochemistry and Biotechnology , University of Thessaly , Larissa , 412 21 , Greece
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23
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Flis A, Fernández AP, Zielinski T, Mengin V, Sulpice R, Stratford K, Hume A, Pokhilko A, Southern MM, Seaton DD, McWatters HG, Stitt M, Halliday KJ, Millar AJ. Defining the robust behaviour of the plant clock gene circuit with absolute RNA timeseries and open infrastructure. Open Biol 2016; 5:rsob.150042. [PMID: 26468131 PMCID: PMC4632509 DOI: 10.1098/rsob.150042] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Our understanding of the complex, transcriptional feedback loops in the circadian clock mechanism has depended upon quantitative, timeseries data from disparate sources. We measure clock gene RNA profiles in Arabidopsis thaliana seedlings, grown with or without exogenous sucrose, or in soil-grown plants and in wild-type and mutant backgrounds. The RNA profiles were strikingly robust across the experimental conditions, so current mathematical models are likely to be broadly applicable in leaf tissue. In addition to providing reference data, unexpected behaviours included co-expression of PRR9 and ELF4, and regulation of PRR5 by GI. Absolute RNA quantification revealed low levels of PRR9 transcripts (peak approx. 50 copies cell−1) compared with other clock genes, and threefold higher levels of LHY RNA (more than 1500 copies cell−1) than of its close relative CCA1. The data are disseminated from BioDare, an online repository for focused timeseries data, which is expected to benefit mechanistic modelling. One data subset successfully constrained clock gene expression in a complex model, using publicly available software on parallel computers, without expert tuning or programming. We outline the empirical and mathematical justification for data aggregation in understanding highly interconnected, dynamic networks such as the clock, and the observed design constraints on the resources required to make this approach widely accessible.
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Affiliation(s)
- Anna Flis
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
| | - Aurora Piñas Fernández
- SynthSys and School of Biological Sciences, University of Edinburgh, C.H. Waddington Building, Edinburgh EH9 3JD, UK
| | - Tomasz Zielinski
- SynthSys and School of Biological Sciences, University of Edinburgh, C.H. Waddington Building, Edinburgh EH9 3JD, UK
| | - Virginie Mengin
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
| | - Ronan Sulpice
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
| | - Kevin Stratford
- EPCC, University of Edinburgh, James Clerk Maxwell Building, Edinburgh EH9 3JZ, UK
| | - Alastair Hume
- SynthSys and School of Biological Sciences, University of Edinburgh, C.H. Waddington Building, Edinburgh EH9 3JD, UK EPCC, University of Edinburgh, James Clerk Maxwell Building, Edinburgh EH9 3JZ, UK
| | - Alexandra Pokhilko
- SynthSys and School of Biological Sciences, University of Edinburgh, C.H. Waddington Building, Edinburgh EH9 3JD, UK Institute of Molecular Cell and Systems Biology, University of Glasgow, Bower Building, Glasgow G12 8QQ, UK
| | - Megan M Southern
- Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Daniel D Seaton
- SynthSys and School of Biological Sciences, University of Edinburgh, C.H. Waddington Building, Edinburgh EH9 3JD, UK
| | - Harriet G McWatters
- SynthSys and School of Biological Sciences, University of Edinburgh, C.H. Waddington Building, Edinburgh EH9 3JD, UK
| | - Mark Stitt
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam-Golm, Germany
| | - Karen J Halliday
- SynthSys and School of Biological Sciences, University of Edinburgh, C.H. Waddington Building, Edinburgh EH9 3JD, UK
| | - Andrew J Millar
- SynthSys and School of Biological Sciences, University of Edinburgh, C.H. Waddington Building, Edinburgh EH9 3JD, UK
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24
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Hernando CE, Romanowski A, Yanovsky MJ. Transcriptional and post-transcriptional control of the plant circadian gene regulatory network. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1860:84-94. [PMID: 27412912 DOI: 10.1016/j.bbagrm.2016.07.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 06/30/2016] [Accepted: 07/03/2016] [Indexed: 11/16/2022]
Abstract
The circadian clock drives rhythms in multiple physiological processes allowing plants to anticipate and adjust to periodic changes in environmental conditions. These physiological rhythms are associated with robust oscillations in the expression of thousands of genes linked to the control of photosynthesis, cell elongation, biotic and abiotic stress responses, developmental processes such as flowering, and the clock itself. Given its pervasive effects on plant physiology, it is not surprising that circadian clock genes have played an important role in the domestication of crop plants and in the improvement of crop productivity. Therefore, identifying the principles governing the dynamics of the circadian gene regulatory network in plants could strongly contribute to further speed up crop improvement. Here we provide an historical as well as a current description of our knowledge of the molecular mechanisms underlying circadian rhythms in plants. This work focuses on the transcriptional and post-transcriptional regulatory layers that control the very core of the circadian clock, and some of its complex interactions with signaling pathways that help synchronize plant growth and development to daily and seasonal changes in the environment. This article is part of a Special Issue entitled: Plant Gene Regulatory Mechanisms and Networks, edited by Dr. Erich Grotewold and Dr. Nathan Springer.
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Affiliation(s)
- C Esteban Hernando
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina, Av. Patricias Argentinas 435, C1405BWE Ciudad de Buenos Aires, Argentina.
| | - Andrés Romanowski
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina, Av. Patricias Argentinas 435, C1405BWE Ciudad de Buenos Aires, Argentina.
| | - Marcelo J Yanovsky
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina, Av. Patricias Argentinas 435, C1405BWE Ciudad de Buenos Aires, Argentina.
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25
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Millar AJ. The Intracellular Dynamics of Circadian Clocks Reach for the Light of Ecology and Evolution. ANNUAL REVIEW OF PLANT BIOLOGY 2016; 67:595-618. [PMID: 26653934 DOI: 10.1146/annurev-arplant-043014-115619] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A major challenge for biology is to extend our understanding of molecular regulation from the simplified conditions of the laboratory to ecologically relevant environments. Tractable examples are essential to make these connections for complex, pleiotropic regulators and, to go further, to link relevant genome sequences to field traits. Here, I review the case for the biological clock in higher plants. The gene network of the circadian clock drives pervasive, 24-hour rhythms in metabolism, behavior, and physiology across the eukaryotes and in some prokaryotes. In plants, the scope of chronobiology is now extending from the most tractable, intracellular readouts to the clock's many effects at the whole-organism level and across the life cycle, including biomass and flowering. I discuss five research areas where recent progress might be integrated in the future, to understand not only circadian functions in natural conditions but also the evolution of the clock's molecular mechanisms.
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Affiliation(s)
- Andrew J Millar
- SynthSys and School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, Scotland, United Kingdom;
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26
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Feeney KA, Hansen LL, Putker M, Olivares-Yañez C, Day J, Eades LJ, Larrondo LF, Hoyle NP, O'Neill JS, van Ooijen G. Daily magnesium fluxes regulate cellular timekeeping and energy balance. Nature 2016; 532:375-9. [PMID: 27074515 PMCID: PMC4886825 DOI: 10.1038/nature17407] [Citation(s) in RCA: 169] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 02/08/2016] [Indexed: 12/15/2022]
Abstract
Circadian clocks are fundamental to the biology of most eukaryotes, coordinating behaviour and physiology to resonate with the environmental cycle of day and night through complex networks of clock-controlled genes. A fundamental knowledge gap exists, however, between circadian gene expression cycles and the biochemical mechanisms that ultimately facilitate circadian regulation of cell biology. Here we report circadian rhythms in the intracellular concentration of magnesium ions, [Mg(2+)]i, which act as a cell-autonomous timekeeping component to determine key clock properties both in a human cell line and in a unicellular alga that diverged from each other more than 1 billion years ago. Given the essential role of Mg(2+) as a cofactor for ATP, a functional consequence of [Mg(2+)]i oscillations is dynamic regulation of cellular energy expenditure over the daily cycle. Mechanistically, we find that these rhythms provide bilateral feedback linking rhythmic metabolism to clock-controlled gene expression. The global regulation of nucleotide triphosphate turnover by intracellular Mg(2+) availability has potential to impact upon many of the cell's more than 600 MgATP-dependent enzymes and every cellular system where MgNTP hydrolysis becomes rate limiting. Indeed, we find that circadian control of translation by mTOR is regulated through [Mg(2+)]i oscillations. It will now be important to identify which additional biological processes are subject to this form of regulation in tissues of multicellular organisms such as plants and humans, in the context of health and disease.
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Affiliation(s)
- Kevin A. Feeney
- MRC Laboratory for Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Louise L. Hansen
- School of Biological Sciences, University of Edinburgh, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Marrit Putker
- MRC Laboratory for Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Consuelo Olivares-Yañez
- Millennium Nucleus for Fungal Integrative and Synthetic Biology, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile
| | - Jason Day
- Department of Earth Sciences, University of Cambridge, Downing St, Cambridge CB2 3EQ, UK
| | - Lorna J. Eades
- School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, UK
| | - Luis F. Larrondo
- Millennium Nucleus for Fungal Integrative and Synthetic Biology, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile
| | - Nathaniel P. Hoyle
- MRC Laboratory for Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - John S. O'Neill
- MRC Laboratory for Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Gerben van Ooijen
- School of Biological Sciences, University of Edinburgh, Max Born Crescent, Edinburgh EH9 3BF, UK
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He B, Nohara K, Park N, Park YS, Guillory B, Zhao Z, Garcia JM, Koike N, Lee CC, Takahashi JS, Yoo SH, Chen Z. The Small Molecule Nobiletin Targets the Molecular Oscillator to Enhance Circadian Rhythms and Protect against Metabolic Syndrome. Cell Metab 2016; 23:610-21. [PMID: 27076076 PMCID: PMC4832569 DOI: 10.1016/j.cmet.2016.03.007] [Citation(s) in RCA: 359] [Impact Index Per Article: 44.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 02/01/2016] [Accepted: 03/14/2016] [Indexed: 02/07/2023]
Abstract
Dysregulation of circadian rhythms is associated with metabolic dysfunction, yet it is unclear whether enhancing clock function can ameliorate metabolic disorders. In an unbiased chemical screen using fibroblasts expressing PER2::Luc, we identified Nobiletin (NOB), a natural polymethoxylated flavone, as a clock amplitude-enhancing small molecule. When administered to diet-induced obese (DIO) mice, NOB strongly counteracted metabolic syndrome and augmented energy expenditure and locomotor activity in a Clock gene-dependent manner. In db/db mutant mice, the clock is also required for the mitigating effects of NOB on metabolic disorders. In DIO mouse liver, NOB enhanced clock protein levels and elicited pronounced gene expression remodeling. We identified retinoid acid receptor-related orphan receptors as direct targets of NOB, revealing a pharmacological intervention that enhances circadian rhythms to combat metabolic disease via the circadian gene network.
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Affiliation(s)
- Baokun He
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Kazunari Nohara
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Noheon Park
- Department of Neuroscience, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Yong-Sung Park
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Bobby Guillory
- Division of Endocrinology, Diabetes and Metabolism, MCL, Center for Translational Research in Inflammatory Diseases, Michael E. DeBakey Veterans Affairs Medical Center, and Department of Medicine, and Molecular and Cell Biology, Dan L. Duncan Cancer Center, Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhaoyang Zhao
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Jose M Garcia
- Division of Endocrinology, Diabetes and Metabolism, MCL, Center for Translational Research in Inflammatory Diseases, Michael E. DeBakey Veterans Affairs Medical Center, and Department of Medicine, and Molecular and Cell Biology, Dan L. Duncan Cancer Center, Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
| | - Nobuya Koike
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Cheng Chi Lee
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Joseph S Takahashi
- Department of Neuroscience, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA; Howard Hughes Medical Institute, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Seung-Hee Yoo
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Zheng Chen
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA.
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Adhvaryu K, Firoozi G, Motavaze K, Lakin-Thomas P. PRD-1, a Component of the Circadian System of Neurospora crassa, Is a Member of the DEAD-box RNA Helicase Family. J Biol Rhythms 2016; 31:258-71. [PMID: 27029286 DOI: 10.1177/0748730416639717] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The circadian rhythms found in almost all organisms are driven by molecular oscillators, including transcription/translation feedback loops (TTFLs). However, TTFL-independent oscillators can drive rhythms in both eukaryotes and prokaryotes. The fungus Neurospora crassa is a model organism for studying the molecular mechanism of the circadian clock. Although a circadian TTFL involving the proteins FRQ, WC-1, and WC-2 is well-characterized in N. crassa, rhythms can still be observed in the absence of this feedback loop. These rhythms are said to be driven by 1 or more FRQ-less oscillator(s) (FLOs). The prd-1 mutation lengthens the period in frq wild type and was previously shown to severely disrupt FRQ-less rhythms in frq null mutants under several different conditions; therefore, the prd-1 gene product is a candidate for a component of a FLO. We report here that prd-1 also disrupts free-running rhythms in wc-1 null mutants, confirming its effects on FRQ-less rhythms. We have now mapped and identified the prd-1 gene as NCU07839, a DEAD-box RNA helicase dbp-2 Complementation with the wild-type gene corrects the rhythm defects of the prd-1 mutant in the complete circadian system (when the FRQ-based TTFL is intact) and also the free-running FRQ-less rhythm on low choline. A PRD-1-GFP fusion protein localizes to the nucleus. The prd-1 mutant has a single base pair change in the first base of an intron that results in abnormally spliced transcripts. FRQ-less rhythms on low choline, or entrained to heat pulses, were only marginally affected in strains carrying deletions of 2 other RNA helicases (prd-6 and msp-8). We conclude that PRD-1 is a member of an RNA helicase family that may be specifically involved in regulating rhythmicity in N. crassa in both the complete circadian system and FLO(s).
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Affiliation(s)
| | | | - Kamyar Motavaze
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario M5T 1R4, Canada
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29
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Ray S, Reddy AB. Cross-talk between circadian clocks, sleep-wake cycles, and metabolic networks: Dispelling the darkness. Bioessays 2016; 38:394-405. [PMID: 26866932 PMCID: PMC4817226 DOI: 10.1002/bies.201500056] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Integration of knowledge concerning circadian rhythms, metabolic networks, and sleep‐wake cycles is imperative for unraveling the mysteries of biological cycles and their underlying mechanisms. During the last decade, enormous progress in circadian biology research has provided a plethora of new insights into the molecular architecture of circadian clocks. However, the recent identification of autonomous redox oscillations in cells has expanded our view of the clockwork beyond conventional transcription/translation feedback loop models, which have been dominant since the first circadian period mutants were identified in fruit fly. Consequently, non‐transcriptional timekeeping mechanisms have been proposed, and the antioxidant peroxiredoxin proteins have been identified as conserved markers for 24‐hour rhythms. Here, we review recent advances in our understanding of interdependencies amongst circadian rhythms, sleep homeostasis, redox cycles, and other cellular metabolic networks. We speculate that systems‐level investigations implementing integrated multi‐omics approaches could provide novel mechanistic insights into the connectivity between daily cycles and metabolic systems.
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Affiliation(s)
- Sandipan Ray
- Department of Clinical Neurosciences, University of Cambridge Metabolic Research Laboratories, National Institutes of Health Biomedical Research Centre, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Akhilesh B Reddy
- Department of Clinical Neurosciences, University of Cambridge Metabolic Research Laboratories, National Institutes of Health Biomedical Research Centre, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
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30
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A brief history of circadian time: The emergence of redox oscillations as a novel component of biological rhythms. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.pisc.2015.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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31
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Patel VR, Ceglia N, Zeller M, Eckel-Mahan K, Sassone-Corsi P, Baldi P. The pervasiveness and plasticity of circadian oscillations: the coupled circadian-oscillators framework. Bioinformatics 2015; 31:3181-8. [PMID: 26049162 DOI: 10.1093/bioinformatics/btv353] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Accepted: 06/02/2015] [Indexed: 01/20/2023] Open
Abstract
MOTIVATION Circadian oscillations have been observed in animals, plants, fungi and cyanobacteria and play a fundamental role in coordinating the homeostasis and behavior of biological systems. Genetically encoded molecular clocks found in nearly every cell, based on negative transcription/translation feedback loops and involving only a dozen genes, play a central role in maintaining these oscillations. However, high-throughput gene expression experiments reveal that in a typical tissue, a much larger fraction ([Formula: see text]) of all transcripts oscillate with the day-night cycle and the oscillating species vary with tissue type suggesting that perhaps a much larger fraction of all transcripts, and perhaps also other molecular species, may bear the potential for circadian oscillations. RESULTS To better quantify the pervasiveness and plasticity of circadian oscillations, we conduct the first large-scale analysis aggregating the results of 18 circadian transcriptomic studies and 10 circadian metabolomic studies conducted in mice using different tissues and under different conditions. We find that over half of protein coding genes in the cell can produce transcripts that are circadian in at least one set of conditions and similarly for measured metabolites. Genetic or environmental perturbations can disrupt existing oscillations by changing their amplitudes and phases, suppressing them or giving rise to novel circadian oscillations. The oscillating species and their oscillations provide a characteristic signature of the physiological state of the corresponding cell/tissue. Molecular networks comprise many oscillator loops that have been sculpted by evolution over two trillion day-night cycles to have intrinsic circadian frequency. These oscillating loops are coupled by shared nodes in a large network of coupled circadian oscillators where the clock genes form a major hub. Cells can program and re-program their circadian repertoire through epigenetic and other mechanisms. AVAILABILITY AND IMPLEMENTATION High-resolution and tissue/condition specific circadian data and networks available at http://circadiomics.igb.uci.edu. CONTACT pfbaldi@ics.uci.edu SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Vishal R Patel
- Department of Computer Science, Institute for Genomics and Bioinformatics
| | - Nicholas Ceglia
- Department of Computer Science, Institute for Genomics and Bioinformatics
| | - Michael Zeller
- Department of Computer Science, Institute for Genomics and Bioinformatics
| | - Kristin Eckel-Mahan
- Department of Biological Chemistry and Center for Epigenetics and Metabolism, University of California, Irvine (UCI), Irvine, CA - 92697, USA
| | - Paolo Sassone-Corsi
- Institute for Genomics and Bioinformatics, Department of Biological Chemistry and Center for Epigenetics and Metabolism, University of California, Irvine (UCI), Irvine, CA - 92697, USA
| | - Pierre Baldi
- Department of Computer Science, Institute for Genomics and Bioinformatics, Department of Biological Chemistry and Center for Epigenetics and Metabolism, University of California, Irvine (UCI), Irvine, CA - 92697, USA
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Affiliation(s)
- Martin Egli
- Department
of Biochemistry, Vanderbilt University,
School of Medicine, Nashville, Tennessee 37232, United States
| | - Carl H. Johnson
- Department
of Biological Sciences, College of Arts and Science, Vanderbilt University, Nashville, Tennessee 37235, United States
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Abstract
As major contributors to global oxygen levels and producers of fatty acids, carotenoids, sterols, and phycocolloids, algae have significant ecological and commercial roles. Early algal models have contributed much to our understanding of circadian clocks at physiological and biochemical levels. The genetic and molecular approaches that identified clock components in other taxa have not been as widely applied to algae. We review results from seven species: the chlorophytes Chlamydomonas reinhardtii, Ostreococcus tauri, and Acetabularia spp.; the dinoflagellates Lingulodinium polyedrum and Symbiodinium spp.; the euglenozoa Euglena gracilis; and the red alga Cyanidioschyzon merolae. The relative simplicity, experimental tractability, and ecological and evolutionary diversity of algal systems may now make them particularly useful in integrating quantitative data from "omic" technologies (e.g., genomics, transcriptomics, metabolomics, and proteomics) with computational and mathematical methods.
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Affiliation(s)
- Zeenat B Noordally
- SynthSys and School of Biological Sciences, University of Edinburgh , Edinburgh EH9 3BF, United Kingdom
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34
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Intestinal CYP2E1: A mediator of alcohol-induced gut leakiness. Redox Biol 2014; 3:40-6. [PMID: 25462064 PMCID: PMC4297927 DOI: 10.1016/j.redox.2014.10.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 10/13/2014] [Accepted: 10/15/2014] [Indexed: 02/07/2023] Open
Abstract
Chronic alcohol use can result in many pathological effects including alcoholic liver disease (ALD). While alcohol is necessary for the development of ALD, only 20-30% of alcoholics develop alcoholic steatohepatitis (ASH) with progressive liver disease leading to cirrhosis and liver failure (ALD). This suggests that while chronic alcohol consumption is necessary it is not sufficient to induce clinically relevant liver damage in the absence of a secondary risk factor. Studies in rodent models and alcoholic patients show that increased intestinal permeability to microbial products like endotoxin play a critical role in promoting liver inflammation in ALD pathogenesis. Therefore identifying mechanisms of alcohol-induced intestinal permeability is important in identifying mechanisms of ALD and for designing new avenues for therapy. Cyp2e1 is a cytochrome P450 enzyme that metabolizes alcohol has been shown to be upregulated by chronic alcohol use and to be a major source of oxidative stress and liver injury in alcoholics and in animal and in vitro models of chronic alcohol use. Because Cyp2e1 is also expressed in the intestine and is upregulated by chronic alcohol use, we hypothesized it could play a role in alcohol-induced intestinal hyperpermeability. Our in vitro studies with intestinal Caco-2 cells and in mice fed alcohol showed that circadian clock proteins CLOCK and PER2 are required for alcohol-induced permeability. We also showed that alcohol increases Cyp2e1 protein and activity but not mRNA in Caco-2 cells and that an inhibitor of oxidative stress or siRNA knockdown of Cyp2e1 prevents the increase in CLOCK or PER2 proteins and prevents alcohol-induced hyperpermeability. With our collaborators we have also shown that Cyp2e1 knockout mice are resistant to alcohol-induced gut leakiness and liver inflammation. Taken together our data support a novel Cyp2e1-circadian clock protein mechanism for alcohol-induced gut leakiness that could provide new avenues for therapy of ALD.
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35
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Cain SW, Yoon J, Shrestha TC, Ralph MR. Retention of a 24-hour time memory in Syrian hamsters carrying the 20-hour short circadian period mutation in casein kinase-1ε (ck1εtau/tau). Neurobiol Learn Mem 2014; 114:171-7. [DOI: 10.1016/j.nlm.2014.06.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Revised: 06/03/2014] [Accepted: 06/04/2014] [Indexed: 01/10/2023]
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Huang Y, McNeil GP, Jackson FR. Translational regulation of the DOUBLETIME/CKIδ/ε kinase by LARK contributes to circadian period modulation. PLoS Genet 2014; 10:e1004536. [PMID: 25211129 PMCID: PMC4161311 DOI: 10.1371/journal.pgen.1004536] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 06/12/2014] [Indexed: 12/02/2022] Open
Abstract
The Drosophila homolog of Casein Kinase I δ/ε, DOUBLETIME (DBT), is required for Wnt, Hedgehog, Fat and Hippo signaling as well as circadian clock function. Extensive studies have established a critical role of DBT in circadian period determination. However, how DBT expression is regulated remains largely unexplored. In this study, we show that translation of dbt transcripts are directly regulated by a rhythmic RNA-binding protein (RBP) called LARK (known as RBM4 in mammals). LARK promotes translation of specific alternative dbt transcripts in clock cells, in particular the dbt-RC transcript. Translation of dbt-RC exhibits circadian changes under free-running conditions, indicative of clock regulation. Translation of a newly identified transcript, dbt-RE, is induced by light in a LARK-dependent manner and oscillates under light/dark conditions. Altered LARK abundance affects circadian period length, and this phenotype can be modified by different dbt alleles. Increased LARK delays nuclear degradation of the PERIOD (PER) clock protein at the beginning of subjective day, consistent with the known role of DBT in PER dynamics. Taken together, these data support the idea that LARK influences circadian period and perhaps responses of the clock to light via the regulated translation of DBT. Our study is the first to investigate translational control of the DBT kinase, revealing its regulation by LARK and a novel role of this RBP in Drosophila circadian period modulation. The CKI family of serine/threonine kinase regulates diverse cellular processes, through binding to and phosphorylation of a variety of protein substrates. In mammals, mutations in two members of the family, CKIε and CKIδ were found to affect circadian period length, causing phenotypes such as altered circadian period in rodents and the Familial Advanced Sleep Phase Syndrome (FASPS) in human. The Drosophila CKI δ/ε homolog DOUBLETIME (DBT) is known to have important roles in development and circadian clock function. Despite extensive studies of DBT function, little is known about how its expression is regulated. In a previous genome-wide study, we identified dbt mRNAs as potential targets of the LARK RBP. Here we describe a detailed study of the regulation of DBT expression by LARK. We found that LARK binds to and regulates translation of dbt mRNA, promoting expression of a smaller isoform; we suggest this regulatory mechanism contributes to circadian period determination. In addition, we have identified a dbt mRNA that exhibits light-induced changes in translational status, in a LARK-dependent manner. Our study is the first to analyze the translational regulation of DBT, setting the stage for similar studies in other contexts and model systems.
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Affiliation(s)
- Yanmei Huang
- Department of Neuroscience, Sackler School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Gerard P McNeil
- Department of Biology, York College, Jamaica, New York, New York, United States of America
| | - F Rob Jackson
- Department of Neuroscience, Sackler School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, United States of America
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37
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Rethinking the clockwork: redox cycles and non-transcriptional control of circadian rhythms. Biochem Soc Trans 2014; 42:1-10. [PMID: 24450621 DOI: 10.1042/bst20130169] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Circadian rhythms are a hallmark of living organisms, observable in all walks of life from primitive bacteria to highly complex humans. They are believed to have evolved to co-ordinate the timing of biological and behavioural processes to the changing environmental needs brought on by the progression of day and night through the 24-h cycle. Most of the modern study of circadian rhythms has centred on so-called TTFLs (transcription-translation feedback loops), wherein a core group of 'clock' genes, capable of negatively regulating themselves, produce oscillations with a period of approximately 24 h. Recently, however, the prevalence of the TTFL paradigm has been challenged by a series of findings wherein circadian rhythms, in the form of redox reactions, persist in the absence of transcriptional cycles. We have found that circadian cycles of oxidation and reduction are conserved across all domains of life, strongly suggesting that non-TTFL mechanisms work in parallel with the canonical genetic processes of timekeeping to generate the cyclical cellular and behavioural phenotypes that we commonly recognize as circadian rhythms.
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38
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Hindle MM, Martin SF, Noordally ZB, van Ooijen G, Barrios-Llerena ME, Simpson TI, Le Bihan T, Millar AJ. The reduced kinome of Ostreococcus tauri: core eukaryotic signalling components in a tractable model species. BMC Genomics 2014; 15:640. [PMID: 25085202 PMCID: PMC4143559 DOI: 10.1186/1471-2164-15-640] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 07/08/2014] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The current knowledge of eukaryote signalling originates from phenotypically diverse organisms. There is a pressing need to identify conserved signalling components among eukaryotes, which will lead to the transfer of knowledge across kingdoms. Two useful properties of a eukaryote model for signalling are (1) reduced signalling complexity, and (2) conservation of signalling components. The alga Ostreococcus tauri is described as the smallest free-living eukaryote. With less than 8,000 genes, it represents a highly constrained genomic palette. RESULTS Our survey revealed 133 protein kinases and 34 protein phosphatases (1.7% and 0.4% of the proteome). We conducted phosphoproteomic experiments and constructed domain structures and phylogenies for the catalytic protein-kinases. For each of the major kinases families we review the completeness and divergence of O. tauri representatives in comparison to the well-studied kinomes of the laboratory models Arabidopsis thaliana and Saccharomyces cerevisiae, and of Homo sapiens. Many kinase clades in O. tauri were reduced to a single member, in preference to the loss of family diversity, whereas TKL and ABC1 clades were expanded. We also identified kinases that have been lost in A. thaliana but retained in O. tauri. For three, contrasting eukaryotic pathways - TOR, MAPK, and the circadian clock - we established the subset of conserved components and demonstrate conserved sites of substrate phosphorylation and kinase motifs. CONCLUSIONS We conclude that O. tauri satisfies our two central requirements. Several of its kinases are more closely related to H. sapiens orthologs than S. cerevisiae is to H. sapiens. The greatly reduced kinome of O. tauri is therefore a suitable model for signalling in free-living eukaryotes.
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Affiliation(s)
| | | | | | | | | | | | | | - Andrew J Millar
- SynthSys and School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JD, UK.
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39
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Kitayama Y, Nishiwaki-Ohkawa T, Sugisawa Y, Kondo T. KaiC intersubunit communication facilitates robustness of circadian rhythms in cyanobacteria. Nat Commun 2014; 4:2897. [PMID: 24305644 PMCID: PMC3863973 DOI: 10.1038/ncomms3897] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 11/08/2013] [Indexed: 02/08/2023] Open
Abstract
The cyanobacterial circadian clock is the only model clock to have been reconstituted in vitro. KaiC, the central clock component, is a homohexameric ATPase with autokinase and autophosphatase activities. Changes in phosphorylation state have been proposed to switch KaiC’s activity between autokinase and autophosphatase. Here we analyse the molecular mechanism underlying the regulation of KaiC’s activity, in the context of its hexameric structure. We reconstitute KaiC hexamers containing different variant protomers, and measure their autophosphatase and autokinase activities. We identify two types of regulatory mechanisms with distinct functions. First, local interactions between adjacent phosphorylation sites regulate KaiC’s activities, coupling the ATPase and nucleotide-binding states at subunit interfaces of the CII domain. Second, the phosphorylation states of the protomers affect the overall activity of KaiC hexamers via intersubunit communication. Our findings indicate that intra-hexameric interactions play an important role in sustaining robust circadian rhythmicity. The cyanobacterial circadian oscillator comprises an autoregulatory loop that is driven by phosphorylation and dephosphorylation of the hexameric kinase KaiC. Kitayama et al. reveal how interactions between KaiC subunits regulate its catalytic activities and ensure robust circadian behaviour.
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Affiliation(s)
- Yohko Kitayama
- Division of Biological Science, Graduate School of Science, Nagoya University and CREST, Japan Science and Technology Agency (JST), Furo-cho, Chikusa-ku, Nagoya 464 8602, Japan
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40
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Spoel SH, van Ooijen G. Circadian redox signaling in plant immunity and abiotic stress. Antioxid Redox Signal 2014; 20:3024-39. [PMID: 23941583 PMCID: PMC4038994 DOI: 10.1089/ars.2013.5530] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 08/13/2013] [Indexed: 11/12/2022]
Abstract
SIGNIFICANCE Plant crops are critically important to provide quality food and bio-energy to sustain a growing human population. Circadian clocks have been shown to deliver an adaptive advantage to plants, vastly increasing biomass production by efficient anticipation to the solar cycle. Plant stress, on the other hand, whether biotic or abiotic, prevents crops from reaching maximum productivity. RECENT ADVANCES Stress is associated with fluctuations in cellular redox and increased phytohormone signaling. Recently, direct links between circadian timekeeping, redox fluctuations, and hormone signaling have been identified. A direct implication is that circadian control of cellular redox homeostasis influences how plants negate stress to ensure growth and reproduction. CRITICAL ISSUES Complex cellular biochemistry leads from perception of stress via hormone signals and formation of reactive oxygen intermediates to a physiological response. Circadian clocks and metabolic pathways intertwine to form a confusing biochemical labyrinth. Here, we aim to find order in this complex matter by reviewing current advances in our understanding of the interface between these networks. FUTURE DIRECTIONS Although the link is now clearly defined, at present a key question remains as to what extent the circadian clock modulates redox, and vice versa. Furthermore, the mechanistic basis by which the circadian clock gates redox- and hormone-mediated stress responses remains largely elusive.
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Affiliation(s)
- Steven H. Spoel
- Institute for Molecular Plant Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Gerben van Ooijen
- Institute for Molecular Plant Sciences, University of Edinburgh, Edinburgh, United Kingdom
- SythSys, University of Edinburgh, Edinburgh, United Kingdom
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Huang Y, Ainsley JA, Reijmers LG, Jackson FR. Translational profiling of clock cells reveals circadianly synchronized protein synthesis. PLoS Biol 2013; 11:e1001703. [PMID: 24348200 PMCID: PMC3864454 DOI: 10.1371/journal.pbio.1001703] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 09/24/2013] [Indexed: 12/03/2022] Open
Abstract
This study describes, for the first time, the rhythmic translational program within circadian
clock cells. The results indicate that most clock cell mRNAs are translated at low-energy times of
either mid-day or mid-night, and also that related cellular functions are coordinately regulated by
the synchronized translation of relevant mRNAs at the same time of day. Genome-wide studies of circadian transcription or mRNA translation have been hindered by the
presence of heterogeneous cell populations in complex tissues such as the nervous system. We
describe here the use of a Drosophila cell-specific translational profiling
approach to document the rhythmic “translatome” of neural clock cells for the first time
in any organism. Unexpectedly, translation of most clock-regulated transcripts—as assayed by
mRNA ribosome association—occurs at one of two predominant circadian phases, midday or
mid-night, times of behavioral quiescence; mRNAs encoding similar cellular functions are translated
at the same time of day. Our analysis also indicates that fundamental cellular
processes—metabolism, energy production, redox state (e.g., the thioredoxin system), cell
growth, signaling and others—are rhythmically modulated within clock cells via synchronized
protein synthesis. Our approach is validated by the identification of mRNAs known to exhibit
circadian changes in abundance and the discovery of hundreds of novel mRNAs that show translational
rhythms. This includes Tdc2, encoding a neurotransmitter synthetic enzyme, which we
demonstrate is required within clock neurons for normal circadian locomotor activity. The circadian clock controls daily rhythms in physiology and behavior via mechanisms that
regulate gene expression. While numerous studies have examined the clock regulation of gene
transcription and documented rhythms in mRNA abundance, less is known about how circadian changes in
protein synthesis contribute to the orchestration of physiological and behavioral programs. Here we
have monitored mRNA ribosomal association (as a proxy for translation) to globally examine the
circadian timing of protein synthesis specifically within clock cells of
Drosophila. The results reveal, for the first time in any organism, the complete
circadian program of protein synthesis (the “circadian translatome”) within these cells.
A novel finding is that most mRNAs within clock cells are translated at one of two predominant
circadian phases—midday or mid-night—times of low energy expenditure. Our work also
finds that many clock cell processes, including metabolism, redox state, signaling,
neurotransmission, and even protein synthesis itself, are coordinately regulated such that mRNAs
required for similar cellular functions are translated in synchrony at the same time of day.
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Affiliation(s)
- Yanmei Huang
- Department of Neuroscience, Sackler School of Biomedical Sciences, Tufts
University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail: (Y.H.);
(F.R.J.)
| | - Joshua A. Ainsley
- Department of Neuroscience, Sackler School of Biomedical Sciences, Tufts
University School of Medicine, Boston, Massachusetts, United States of America
| | - Leon G. Reijmers
- Department of Neuroscience, Sackler School of Biomedical Sciences, Tufts
University School of Medicine, Boston, Massachusetts, United States of America
| | - F. Rob Jackson
- Department of Neuroscience, Sackler School of Biomedical Sciences, Tufts
University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail: (Y.H.);
(F.R.J.)
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van Ooijen G, Martin SF, Barrios-Llerena ME, Hindle M, Le Bihan T, O'Neill JS, Millar AJ. Functional analysis of the rodent CK1tau mutation in the circadian clock of a marine unicellular alga. BMC Cell Biol 2013; 14:46. [PMID: 24127907 PMCID: PMC3852742 DOI: 10.1186/1471-2121-14-46] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 10/04/2013] [Indexed: 11/18/2022] Open
Abstract
Background Casein Kinase 1 (CK1) is one of few proteins known to affect cellular timekeeping across metazoans, and the naturally occurring CK1tau mutation shortens circadian period in mammals. Functional conservation of a timekeeping function for CK1 in the green lineage was recently identified in the green marine unicell Ostreococcus tauri, in spite of the absence of CK1's transcriptional targets known from other species. The short-period phenotype of CK1tau mutant in mammals depends specifically on increased CK1 activity against PERIOD proteins. To understand how CK1 acts differently upon the algal clock, we analysed the cellular and proteomic effects of CK1tau overexpression in O. tauri. Results Overexpression of the CK1tau in O. tauri induces period lengthening identical to overexpression of wild-type CK1, in addition to resistance to CK1 inhibitor IC261. Label-free quantitative mass spectrometry of CK1tau overexpressing algae revealed a total of 58 unique phospho-sites that are differentially responsive to CK1tau. Combined with CK1 phosphorylation site prediction tools and previously published wild-type CK1-responsive peptides, this study results in a highly stringent list of upregulated phospho-sites, derived from proteins containing ankyrin repeats, kinase proteins, and phosphoinositide-binding proteins. Conclusions The identical phenotype for overexpression of wild-type CK1 and CK1tau is in line with the absence of critical targets for rodent CK1tau in O. tauri. Proteomic analyses reveal that two thirds of previously reported CK1 overexpression-responsive phospho-sites are shared with CK1tau. These results indicate that the two alleles are functionally indiscriminate in O. tauri, and verify the identified cellular CK1 target proteins in a minimal circadian model organism.
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Affiliation(s)
- Gerben van Ooijen
- SynthSys, University of Edinburgh, Waddington Building, The King's Buildings, Mayfield Road, Edinburgh EH9 3JD, UK.
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van Ooijen G, Hindle M, Martin SF, Barrios-Llerena M, Sanchez F, Bouget FY, O’Neill JS, Le Bihan T, Millar AJ. Functional analysis of Casein Kinase 1 in a minimal circadian system. PLoS One 2013; 8:e70021. [PMID: 23936135 PMCID: PMC3723912 DOI: 10.1371/journal.pone.0070021] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 06/14/2013] [Indexed: 12/04/2022] Open
Abstract
The Earth's rotation has driven the evolution of cellular circadian clocks to facilitate anticipation of the solar cycle. Some evidence for timekeeping mechanism conserved from early unicellular life through to modern organisms was recently identified, but the components of this oscillator are currently unknown. Although very few clock components appear to be shared across higher species, Casein Kinase 1 (CK1) is known to affect timekeeping across metazoans and fungi, but has not previously been implicated in the circadian clock in the plant kingdom. We now show that modulation of CK1 function lengthens circadian rhythms in Ostreococcustauri, a unicellular marine algal species at the base of the green lineage, separated from humans by ~1.5 billion years of evolution. CK1 contributes to timekeeping in a phase-dependent manner, indicating clock-mediated gating of CK1 activity. Label-free proteomic analyses upon overexpression as well as inhibition revealed CK1-responsive phosphorylation events on a set of target proteins, including highly conserved potentially clock-relevant cellular regulator proteins. These results have major implications for our understanding of cellular timekeeping and can inform future studies in any circadian organism.
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Affiliation(s)
- Gerben van Ooijen
- SynthSys, University of Edinburgh, Edinburgh, United Kingdom
- Institute for Molecular Plant Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Institute of Structural and Molecular Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Matthew Hindle
- SynthSys, University of Edinburgh, Edinburgh, United Kingdom
| | - Sarah F. Martin
- SynthSys, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Frédéric Sanchez
- Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, Paris, France
- Laboratoire d’Océanographie Microbienne, Observatoire Océanologique, Banyuls-sur-Mer, France
| | - François-Yves Bouget
- Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, Paris, France
- Laboratoire d’Océanographie Microbienne, Observatoire Océanologique, Banyuls-sur-Mer, France
| | - John S. O’Neill
- Medical Research Council Laboratory for Molecular Biology, Cambridge, United Kingdom
| | - Thierry Le Bihan
- SynthSys, University of Edinburgh, Edinburgh, United Kingdom
- Institute of Structural and Molecular Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Andrew J. Millar
- SynthSys, University of Edinburgh, Edinburgh, United Kingdom
- Institute of Structural and Molecular Biology, University of Edinburgh, Edinburgh, United Kingdom
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Forsyth CB, Voigt RM, Shaikh M, Tang Y, Cederbaum AI, Turek FW, Keshavarzian A. Role for intestinal CYP2E1 in alcohol-induced circadian gene-mediated intestinal hyperpermeability. Am J Physiol Gastrointest Liver Physiol 2013; 305:G185-95. [PMID: 23660503 PMCID: PMC3725682 DOI: 10.1152/ajpgi.00354.2012] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have shown that alcohol increases Caco-2 intestinal epithelial cell monolayer permeability in vitro by inducing the expression of redox-sensitive circadian clock proteins CLOCK and PER2 and that these proteins are necessary for alcohol-induced hyperpermeability. We hypothesized that alcohol metabolism by intestinal Cytochrome P450 isoform 2E1 (CYP2E1) could alter circadian gene expression (Clock and Per2), resulting in alcohol-induced hyperpermeability. In vitro Caco-2 intestinal epithelial cells were exposed to alcohol, and CYP2E1 protein, activity, and mRNA were measured. CYP2E1 expression was knocked down via siRNA and alcohol-induced hyperpermeability, and CLOCK and PER2 protein expression were measured. Caco-2 cells were also treated with alcohol or H₂O₂ with or without N-acetylcysteine (NAC) anti-oxidant, and CLOCK and PER2 proteins were measured at 4 or 2 h. In vivo Cyp2e1 protein and mRNA were also measured in colon tissue from alcohol-fed mice. Alcohol increased CYP2E1 protein by 93% and enzyme activity by 69% in intestinal cells in vitro. Alcohol feeding also increased mouse colonic Cyp2e1 protein by 73%. mRNA levels of Cyp2e1 were not changed by alcohol in vitro or in mouse intestine. siRNA knockdown of CYP2E1 in Caco-2 cells prevented alcohol-induced hyperpermeability and induction of CLOCK and PER2 proteins. Alcohol-induced and H₂O₂-induced increases in intestinal cell CLOCK and PER2 were significantly inhibited by treatment with NAC. We concluded that our data support a novel role for intestinal CYP2E1 in alcohol-induced intestinal hyperpermeability via a mechanism involving CYP2E1-dependent induction of oxidative stress and upregulation of circadian clock proteins CLOCK and PER2.
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Affiliation(s)
- Christopher B. Forsyth
- Departments of 1Internal Medicine, Division of Digestive Diseases and Nutrition, ,2Biochemistry,
| | - Robin M. Voigt
- Departments of 1Internal Medicine, Division of Digestive Diseases and Nutrition,
| | - Maliha Shaikh
- Departments of 1Internal Medicine, Division of Digestive Diseases and Nutrition,
| | - Yueming Tang
- Departments of 1Internal Medicine, Division of Digestive Diseases and Nutrition,
| | - Arthur I. Cederbaum
- 3Mount Sinai School of Medicine, Department of Pharmacology and System Therapeutics, New York, New York;
| | - Fred W. Turek
- 8Northwestern University Feinberg School of Medicine, Chicago; ,4Center for Sleep and Circadian Biology, Department of Neurobiology, Northwestern University, Evanston, Illinois;
| | - Ali Keshavarzian
- Departments of 1Internal Medicine, Division of Digestive Diseases and Nutrition, ,5Pharmacology, and ,6Molecular Biophysics and Physiology, Rush University Medical Center, Chicago; ,7Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, The Netherlands
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Ruan HB, Singh JP, Li MD, Wu J, Yang X. Cracking the O-GlcNAc code in metabolism. Trends Endocrinol Metab 2013; 24:301-9. [PMID: 23647930 PMCID: PMC3783028 DOI: 10.1016/j.tem.2013.02.002] [Citation(s) in RCA: 178] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 02/16/2013] [Accepted: 02/17/2013] [Indexed: 12/15/2022]
Abstract
Nuclear, cytoplasmic, and mitochondrial proteins are extensively modified by O-linked β-N-acetylglucosamine (O-GlcNAc) moieties. This sugar modification regulates fundamental cellular processes in response to diverse nutritional and hormonal cues. The enzymes O-GlcNAc transferase (OGT) and O-linked β-N-acetylglucosaminase (O-GlcNAcase) mediate the addition and removal of O-GlcNAc, respectively. Aberrant O-GlcNAcylation has been implicated in a plethora of human diseases, including diabetes, cancer, aging, cardiovascular disease, and neurodegenerative disease. Because metabolic dysregulation is a vital component of these diseases, unraveling the roles of O-GlcNAc in metabolism is of emerging importance. Here, we review the current understanding of the functions of O-GlcNAc in cell signaling and gene transcription involved in metabolism, and focus on its relevance to diabetes, cancer, circadian rhythm, and mitochondrial function.
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Affiliation(s)
- Hai-Bin Ruan
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06519, U.S.A
- Section of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06519, U.S.A
| | - Jay Prakash Singh
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06519, U.S.A
- Section of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06519, U.S.A
| | - Min-Dian Li
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06519, U.S.A
- Section of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06519, U.S.A
- Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06519, U.S.A
| | - Jing Wu
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06519, U.S.A
- Section of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06519, U.S.A
- School of Life Science and Technology, Xi'an Jiaotong University Xi'an, Shaanxi 710049, China
| | - Xiaoyong Yang
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06519, U.S.A
- Section of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06519, U.S.A
- Department of Cellular & Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06519, U.S.A
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Rey G, Reddy AB. Connecting cellular metabolism to circadian clocks. Trends Cell Biol 2013; 23:234-41. [PMID: 23391694 DOI: 10.1016/j.tcb.2013.01.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 01/04/2013] [Accepted: 01/04/2013] [Indexed: 12/31/2022]
Abstract
The circadian clock is a cellular timekeeping mechanism that helps organisms to organize their behaviour and physiology around daily alternations of days and nights. In humans, misalignment of an individual's internal clock with its environment is associated with adverse health consequences, including metabolic disorders and cancers. In current models of the eukaryotic circadian oscillator, transcription/translation feedback loops (TTFLs) are considered the prime mechanism sustaining intracellular rhythms. The discovery of many cytosolic loops has extended the TTFL model by embedding it in cellular physiology. Recently, however, several studies have revealed metabolic rhythms that are independent of transcription, questioning the TTFL model as the sole cellular timekeeping mechanism. Thus, the time has come to carefully reassess these models of the clockwork in a broad cellular context to integrate its genetic, cytosolic, and metabolic components.
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Affiliation(s)
- Guillaume Rey
- Department of Clinical Neurosciences, University of Cambridge Metabolic Research Laboratories, NIHR Biomedical Research Centre, Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
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Shi M, Zheng X. Interactions between the circadian clock and metabolism: there are good times and bad times. Acta Biochim Biophys Sin (Shanghai) 2013; 45:61-9. [PMID: 23257295 DOI: 10.1093/abbs/gms110] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
An endogenous circadian (∼24 h) clock regulates rhythmic processes of physiology, metabolism and behavior in most living organisms. While able to free-run under constant conditions, the circadian clock is coupled to day : night cycles to increase its amplitude and align the phase of circadian rhythms to the right time of the day. Disruptions of the circadian clock are correlated with brain dysfunctions, cardiovascular diseases and metabolic disorders. In this review, we focus on the interactions between the circadian clock and metabolism. We discuss recent findings on circadian clock regulation of feeding behavior and rhythmic expression of metabolic genes, and present evidence of metabolic input to the circadian clock. We emphasize how misalignment of circadian clocks within the body and with environmental cycles or daily schedules leads to the increasing prevalence of metabolic syndromes in modern society.
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Affiliation(s)
- Mi Shi
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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48
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Hwang W, Lang MJ. Nucleotide-dependent control of internal strains in ring-shaped AAA+ motors. Cell Mol Bioeng 2012; 6:65-73. [PMID: 23526741 DOI: 10.1007/s12195-012-0264-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The AAA+ (ATPase Associated with various cellular Activities) machinery represents an extremely successful and widely used design plan for biological motors. Recently found crystal structures are beginning to reveal nucleotide-dependent conformational changes in the canonical hexameric rings of the AAA+ motors. However, the physical mechanism by which ATP binding on one subunit allosterically propagates across the entire ring remains to be found. Here we analyze and compare structural organization of three ring-shaped AAA+ motors, ClpX, HslU, and dynein. By constructing multimers using subunits of identical conformations, we find that individual subunits locally possess helical geometries with varying pitch, radius, chirality, and symmetry number. These results suggest that binding of an ATP to a subunit imposes conformational constraint that must be accommodated by more flexible nucleotide-free subunits to relieve mechanical strain on the ring. Local deformation of the ring contour and subsequent propagation of strains may be a general strategy that AAA+ motors adopt to generate force while achieving functional diversity.
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Affiliation(s)
- Wonmuk Hwang
- Department of Biomedical Engineering, Materials Science & Engineering Program, Texas A&M University, College Station, TX 77843, U.S.A
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Partonen T. Hypothesis: Cryptochromes and Brown Fat are Essential for Adaptation and Affect Mood and Mood-Related Behaviors. Front Neurol 2012; 3:157. [PMID: 23133436 PMCID: PMC3488760 DOI: 10.3389/fneur.2012.00157] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 10/16/2012] [Indexed: 01/04/2023] Open
Abstract
Solar radiation and ambient temperature have acted as selective physical forces among populations and thereby guided species distributions in the globe. Circadian clocks are universal and evolve when subjected to selection, and their properties contribute to variations in fitness within specific environments. Concerning humans, as compared to the remaining, the "evening owls" have a greater deviation from the 24 h cycle, are under a greater pressure to circadian desynchrony and more prone to a cluster of health hazards with the increased mortality. Because of their position in the hierarchy and repressive actions, cryptochromes are the key components of the feedback loops on which circadian clocks are built. Based on the evidence a new hypothesis is formulated in which brown adipocytes with their cryptochromes are responsive to a broad range of physical stimuli from the habitat and through their activity ensure adaptation of the individual. The over-activated brown adipose tissue with deficient cryptochromes might induce disrupted thermoregulation and circadian desynchrony, and thereby contribute to lowered mood and pronounced depressive behaviors.
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Affiliation(s)
- Timo Partonen
- Department of Mental Health and Substance Abuse Services, National Institute for Health and Welfare Helsinki, Finland ; Department of Psychiatry, University of Helsinki Helsinki, Finland
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