Sci. STKE, 18 December 2007
Biochemistry Circadian Rhythm Methods
L. Bryan Ray1 and Pamela J. Hines2
1Science, Sciences STKE, AAAS, Washington, DC 20005, USA
Circadian rhythms in plants and animals appear to be coupled to periodic changes in activity of metabolic pathways (see the Perspective by Imaizumi et al.). Yin et al. describe a molecular mechanism that may contribute to the coordination of these biochemical processes. Rev-erb controls transcription of the gene encoding the circadian clock component Bmal1. Rev-erb binds to and is regulated by heme, which stabilizes Rev-erb in a repressor complex, which in turn can block production of gluconeogenic enzymes. Thus, Rev-erb acts as a heme sensor to coordinate the cellular clock, glucose homeostasis, and energy metabolism in human liver cells. Studying Arabidopsis, Dodd et al. now show that a cytoplasmic signaling molecule, cyclic adenosine diphosphate ribose (cADPR), is also a component of the clock mechanism. Perturbations to the feedback loop including cADPR result in instabilities in the clock and disruptions in the daily oscillations of cytoplasmic Ca2+ release.
L. Yin, N. Wu, J. C. Curtin, M. Qatanani, N. R. Szwergold, R. A. Reid, G. M. Waitt, D. J. Parks, K. H. Pearce, G. B. Wisely, M. A. Lazar, Rev-erb, a heme sensor that coordinates metabolic and circadian pathways. Science 318, 1786-1789 (2007). [Abstract] [Full Text]
A. N. Dodd, M. J. Gardner, C. T. Hotta, K. E. Hubbard, N. Dalchau, J. Love, J.-M. Assie, F. C. Robertson, M. K. Jakobsen, J. Gonçalves, D. Sanders, A. A. R. Webb, The Arabidopsis circadian clock incorporates a cADPR-based feedback loop. Science 318, 1789-1792 (2007). [Abstract] [Full Text]
Citation: L. B. Ray, P. J. Hines, Circadian Rhythm Methods. Sci. STKE 2007, tw460 (2007).
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