title: Metabolic compensation and circadian resilience in prokaryotic cyanobacteria.
abstract: For a biological oscillator to function as a circadian pacemaker that confers a fitness advantage, its timing functions must be stable in response to environmental and metabolic fluctuations. One such stability enhancer, temperature compensation, has long been a defining characteristic of these timekeepers. However, an accurate biological timekeeper must also resist changes in metabolism, and this review suggests that temperature compensation is actually a subset of a larger phenomenon, namely metabolic compensation, which maintains the frequency of circadian oscillators in response to a host of factors that impinge on metabolism and would otherwise destabilize these clocks. The circadian system of prokaryotic cyanobacteria is an illustrative model because it is composed of transcriptional and nontranscriptional oscillators that are coupled to promote resilience. Moreover, the cyanobacterial circadian program regulates gene activity and metabolic pathways, and it can be manipulated to improve the expression of bioproducts that have practical value.
authors.affiliation: Departments of 1Biological Sciences.
authors.forename: Carl Hirschie
authors.initials: CH
authors.lastname: Johnson
authors.forename: Martin
authors.initials: M
authors.lastname: Egli
mesh_terms: D001426:Bacterial Proteins / Q000502:physiology; D057906:Circadian Clocks; D002940:Circadian Rhythm / Q000502:physiology*; D056925:Circadian Rhythm Signaling Peptides and Proteins / Q000502:physiology; D000458:Cyanobacteria / Q000502:physiology*; D025461:Feedback, Physiological; D015964:Gene Expression Regulation, Bacterial; D006706:Homeostasis; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational; D013696:Temperature; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D056925:Circadian Rhythm Signaling Peptides and Proteins; C114271:KaiC protein, cyanobacteria
keywords: Kai; KaiABC; cell division; circadian; cyanobacteria; homeostasis; in vitro oscillator; metabolism; nontranscriptional oscillator; oscillator; robustness; stability; temperature compensation