KaiA-stimulated KaiC phosphorylation in circadian timing loops in cyanobacteria
Open Access
- 21 October 2002
- journal article
- research article
- Published by National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 99 (24) , 15788-15793
Abstract
Cyanobacterial clock proteins KaiA and KaiC are proposed as positive and negative regulators in the autoregulatory circadiankaiBCexpression, respectively. Here, we show that activation ofkaiBCexpression bykaiArequires KaiC, suggesting a positive feedback control in the cyanobacterial clockwork. We found that robust circadian phosphorylation of KaiC. KaiA was essential forin vivoKaiC phosphorylation and activatedin vitroKaiC autophosphorylation. These effects of KaiA were attenuated by thekaiA2long period mutation. Both the long period phenotype and the abnormal KaiC phosphorylation in this mutant were suppressed by a previously undocumentedkaiCmutation. We propose that KaiA-stimulated circadian KaiC phosphorylation is important for circadian timing.Keywords
This publication has 17 references indexed in Scilit:
- Structure and function from the circadian clock protein KaiA of Synechococcus elongatus : A potential clock input mechanismProceedings of the National Academy of Sciences, 2002
- Mutations in KaiA, a clock protein, extend the period of circadian rhythm in the cyanobacterium Synechococcus elongatus PCC 7942Microbiology, 2002
- Circadian programming in cyanobacteriaSeminars in Cell & Developmental Biology, 2001
- Circadian clock‐protein expression in cyanobacteria: rhythms and phase settingThe EMBO Journal, 2000
- A KaiC-Interacting Sensory Histidine Kinase, SasA, Necessary to Sustain Robust Circadian Oscillation in CyanobacteriaCell, 2000
- Physical interactions among circadian clock proteins KaiA, KaiB and KaiC in cyanobacteriaThe EMBO Journal, 1999
- Expression of a Gene Cluster kaiABC as a Circadian Feedback Process in CyanobacteriaScience, 1998
- Circadian Clock Mutants of CyanobacteriaScience, 1994
- Negative Feedback Defining a Circadian Clock: Autoregulation of the Clock Gene frequencyScience, 1994
- Discovery of a protein phosphatase activity encoded in the genome of bacteriophage λ. Probable identity with open reading frame 221Biochemical Journal, 1989