The cyanobacterial circadian clock is based on the intrinsic ATPase activity of KaiC

McClung, C. Robertson

doi:10.1073/pnas.0708757104

Cited by 6 publications

(4 citation statements)

References 18 publications

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“…contributed equally to this work. 2 To whom correspondence should be addressed: Email: sgolden@ucsd.edu. To examine the effect of DBMIB on KaiA in vitro, we performed reactions using purified KaiA incubated for 20 min with either oxidized or reduced DBMIB and subjected the samples to native polyacrylamide gel electrophoresis (PAGE).…”

Section: Resultsmentioning

confidence: 99%

“…C ircadian rhythms of physiological processes occur in diverse prokaryotes and eukaryotes from cyanobacteria to humans (1,2). The biochemical nature of the endogenous clock that drives these rhythms has been described in rich detail for the cyanobacterium Synechococcus elongatus, which uses a circadian oscillator that is evolutionarily and mechanistically distinct from those of eukaryotic organisms.…”

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confidence: 99%

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The KaiA protein of the cyanobacterial circadian oscillator is modulated by a redox-active cofactor

Wood¹,

Bridwell‐Rabb

Kim

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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The circadian rhythms exhibited in the cyanobacterium Synechococcus elongatus are generated by an oscillator comprised of the proteins KaiA, KaiB, and KaiC. An external signal that commonly affects the circadian clock is light. Previously, we reported that the bacteriophytochrome-like protein CikA passes environmental signals to the oscillator by directly binding a quinone and using cellular redox state as a measure of light in this photosynthetic organism. Here, we report that KaiA also binds the quinone analog 2,5-dibromo-3-methyl-6-isopropyl- p -benzoquinone (DBMIB), and the oxidized form of DBMIB, but not its reduced form, decreases the stability of KaiA in vivo, causes multimerization in vitro, and blocks KaiA stimulation of KaiC phosphorylation, which is central to circadian oscillation. Our data suggest that KaiA directly senses environmental signals as changes in redox state and modulates the circadian clock.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

The KaiA protein of the cyanobacterial circadian oscillator is modulated by a redox-active cofactor

Wood¹,

Bridwell‐Rabb

Kim

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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“…This difference in single-cell precision and intercellular communication echoes two additional differences between the systems: (1) rhythmic transcriptional oscillations are global in cyanobacteria, because most if not all genes are controlled by the same fundamental mechanism (Liu et al 1995;Woelfle and Johnson 2006); in contrast, animal genes under circadian transcriptional regulation are regulated by different factors with only a minority apparently affected directly by the CLK-CYC heterodimer (McDonald and Rosbash 2001). (2) The KaiC kinase and phosphatase appear to be unique and of singular importance to timekeeping (McClung 2007;Terauchi et al 2007). In contrast, animal rhythms have recruited several common enzymes involved in many other cellular processes (Kloss et al 1998;Price et al 1998;Lin et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Transcriptional Feedback and Definition of the Circadian Pacemaker inDrosophilaand Animals

Rosbash¹,

Bradley²,

Kadener³

et al. 2007

Cold Spring Harbor Symposia on Quantitative Biology

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The modern era of Drosophila circadian rhythms began with the landmark Benzer and Konopka paper and its definition of the period gene. The recombinant DNA revolution then led to the cloning and sequencing of this gene. This work did not result in a coherent view of circadian rhythm biochemistry, but experiments eventually gave rise to a transcription-centric view of circadian rhythm generation. Although these circadian transcription-translation feedback loops are still important, their contribution to core timekeeping is under challenge. Indeed, kinases and posttranslational regulation may be more important, based in part on recent in vitro work from cyanobacteria. In addition, kinase mutants or suspected kinase substrate mutants have unusually large period effects in Drosophila. This chapter discusses our recent experiments, which indicate that circadian transcription does indeed contribute to period determination in this system. We propose that cyanobacteria and animal clocks reflect two independent origins of circadian rhythms.

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“…In Arabidopsis , a repressilator structure was recently identified as a core integrated element of the complex machinery of the circadian clock [ 45 ]. The cyanobacterium circadian clock is a unique transcription-independent oscillator (motif C) whose components KaiA, KaiB and KaiC have been demonstrated to compose a temperature-compensated circadian clock in the presence of ATP in vitro [ 52 ].…”

Section: Resultsmentioning

confidence: 99%

Robust network topologies for generating oscillations with temperature-independent periods

Ouyang

Wang

2017

PLoS ONE

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Nearly all living systems feature a temperature-independent oscillation period in circadian clocks. This ubiquitous property occurs at the system level and is rooted in the network architecture of the clock machinery. To investigate the mechanism of this prominent property of the circadian clock and provide general guidance for generating robust genetic oscillators with temperature-compensated oscillations, we theoretically explored the design principle and core network topologies preferred by oscillations with a temperature-independent period. By enumerating all topologies of genetic regulatory circuits with three genes, we obtained four network motifs, namely, a delayed negative feedback oscillator, repressilator, activator-inhibitor oscillator and substrate-depletion oscillator; hybrids of these motifs constitute the vast majority of target network topologies. These motifs are biased in their capacities for achieving oscillations and the temperature sensitivity of the period. The delayed negative feedback oscillator and repressilator are more robust for oscillations, whereas the activator-inhibitor and substrate-depletion oscillators are superior for maintaining a temperature-independent oscillation period. These results suggest that thermally robust oscillation can be more plausibly achieved by hybridizing these two categories of network motifs. Antagonistic balance and temperature insulation mechanisms for achieving temperature compensation are typically found in these topologies with temperature robustness. In the temperature insulation approach, the oscillation period relies on very few parameters, and these parameters are influenced only slightly by temperature. This approach prevents the temperature from affecting the oscillation period and generates circadian rhythms that are robust against environmental perturbations.

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The cyanobacterial circadian clock is based on the intrinsic ATPase activity of KaiC

Cited by 6 publications

References 18 publications

The KaiA protein of the cyanobacterial circadian oscillator is modulated by a redox-active cofactor

The KaiA protein of the cyanobacterial circadian oscillator is modulated by a redox-active cofactor

Transcriptional Feedback and Definition of the Circadian Pacemaker inDrosophilaand Animals

Robust network topologies for generating oscillations with temperature-independent periods

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