Dynamics of two phosphorelays controlling cell cycle progression in 1 Caulobacter crescentus
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main article
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Author(s)
Chen, Y. Erin
Tsokos, Christos G.
Biondi, Emanuele G.
Perchuk, Barrett
Laub, Michael T
Date Issued
September 2009
Journal
Journal of Bacteriology
Publisher
American Society for Microbiology
Citation
Chen, Y. Erin et al. “Dynamics of Two Phosphorelays Controlling Cell Cycle Progression in Caulobacter crescentus.” The Journal of Bacteriology 191.24 (2009): 7417-7429. © 2009 Journal of Bacteriology.
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Author's final manuscript
Abstract
In Caulobacter crescentus, progression through the cell cycle is governed by the periodic activation and inactivation of the master regulator CtrA. Two phosphorelays, each initiating with the histidine kinase CckA, promote CtrA activation by driving its phosphorylation and by inactivating its proteolysis. Here, we examined whether the CckA phosphorelays also influence the downregulation of CtrA. We demonstrate that CckA is bifunctional, capable of acting as either a kinase or phosphatase to drive the activation or inactivation, respectively, of CtrA. By identifying mutations that uncouple these two activities, we show that CckA's phosphatase activity is important for downregulating CtrA prior to DNA replication initiation in vivo but that other phosphatases may exist. Our results demonstrate that cell cycle transitions in Caulobacter require and are likely driven by the toggling of CckA between its kinase and phosphatase states. More generally, our results emphasize how the bifunctional nature of histidine kinases can help switch cells between mutually exclusive states.
MIT Department
Massachusetts Institute of Technology. Department of Biology
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DOI of Published Version
https://doi.org/10.1128/JB.00992-09
