title: Metabolic Cycles in Yeast Share Features Conserved among Circadian Rhythms.
abstract: Cell-autonomous circadian rhythms allow organisms to temporally orchestrate their internal state to anticipate and/or resonate with the external environment. Although ∼24-hr periodicity is observed across aerobic eukaryotes, the central mechanism has been hard to dissect because few simple models exist, and known clock proteins are not conserved across phylogenetic kingdoms. In contrast, contributions to circadian rhythmicity made by a handful of post-translational mechanisms, such as phosphorylation of clock proteins by casein kinase 1 (CK1) and glycogen synthase kinase 3 (GSK3), appear conserved among phyla. These kinases have many other essential cellular functions and are better conserved in their contribution to timekeeping than any of the clock proteins they phosphorylate. Rhythmic oscillations in cellular redox state are another universal feature of circadian timekeeping, e.g., over-oxidation cycles of abundant peroxiredoxin proteins. Here, we use comparative chronobiology to distinguish fundamental clock mechanisms from species and/or tissue-specific adaptations and thereby identify features shared between circadian rhythms in mammalian cells and non-circadian temperature-compensated respiratory oscillations in budding yeast. We find that both types of oscillations are coupled with the cell division cycle, exhibit period determination by CK1 and GSK3, and have peroxiredoxin over-oxidation cycles. We also explore how peroxiredoxins contribute to YROs. Our data point to common mechanisms underlying both YROs and circadian rhythms and suggest two interpretations: either certain biochemical systems are simply permissive for cellular oscillations (with frequencies from hours to days) or this commonality arose via divergence from an ancestral cellular clock.
authors: Department of Biological Sciences, Columbia University, 617 Fairchild Building, 1212 Amsterdam Avenue, Mail Code 2442, New York, NY 10027, USA. Electronic address: hc2415@columbia.edu.
authors: Helen C
authors: HC
authors: Causton
authors: MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
authors: Kevin A
authors: KA
authors: Feeney
authors: Department of Biological Sciences, Columbia University, 617 Fairchild Building, 1212 Amsterdam Avenue, Mail Code 2442, New York, NY 10027, USA.
authors: Christine A
authors: CA
authors: Ziegler
authors: MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK. Electronic address: oneillj@mrc-lmb.cam.ac.uk.
authors: John S
authors: JS
authors: O'Neill
mesh_terms: D000818:Animals; D056926:CLOCK Proteins / Q000378:metabolism*; D047389:Casein Kinase I / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division / Q000235:genetics; D057906:Circadian Clocks / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D038362:Glycogen Synthase Kinase 3 / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D054464:Peroxiredoxins / Q000378:metabolism; D010766:Phosphorylation; D010802:Phylogeny; D015003:Yeasts
chemical_list: D054464:Peroxiredoxins; D056926:CLOCK Proteins; D047389:Casein Kinase I; D038362:Glycogen Synthase Kinase 3