CikA, a bacteriophytochrome that resets the cyanobacterial circadian clock.
The circadian oscillator of the cyanobacterium Synechococcus elongatus, like those in eukaryotes, is entrained by environmental cues. Inactivation of the gene cikA (circadian input kinase) shortens the circadian period of gene expression rhythms in S. elongatus by approximately 2 hours, changes the phasing of a subset of rhythms, and nearly abolishes resetting of phase by a pulse of darkness. The CikA protein sequence reveals that it is a divergent bacteriophytochrome with characteristic histidine protein kinase motifs and a cryptic response regulator motif. CikA is likely a key component of a pathway that provides environmental input to the circadian oscillator in S. elongatus.
Department of Biology, Texas A&M University, College Station, TX 77843-3258, USA.
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Schmitz
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Katayama
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Williams
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Kondo
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Golden
D000483:Alleles; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D001683:Biological Clocks / Q000235:genetics / Q000502:physiology; D002940:Circadian Rhythm / Q000235:genetics / Q000502:physiology; D000458:Cyanobacteria / Q000235:genetics / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D017930:Genes, Reporter; D008163:Luminescent Measurements; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D016415:Sequence Alignment
D001426:Bacterial Proteins; D011494:Protein Kinases; C411989:CikA protein, bacteria