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. Author manuscript; available in PMC: 2018 Oct 5.
Published in final edited form as: Biochim Biophys Acta Gene Regul Mech. 2018 Oct 10;1861(10):952–961. doi: 10.1016/j.bbagrm.2018.08.006

Fig. 1. Cell cycle regulation in Caulobacter crescentus by the CckA-CtrA pathway.

Fig. 1

(A) Schematic representation of the dual switching of CckA between the kinase mode (blue) and the phosphatase mode (orange) in the swarmer and the stalked cell compartments, respectively. The graded bars indicate the time during which CtrA (black) is present during the cell cycle. (B) The bidirectional flow of phosphate between CckA, ChpT and CtrA. In the swarmer cells, CckA transfers the phosphate group to the phosphotranferase, ChpT, which further donates the phosphate to CtrA. The active phosphorylated form of CtrA (CtrA~P) can bind to various target promoters of several cell cycle regulated genes, as well as repress the initiation of chromosome replication. (C) Growth of ∆nstA cells overproducing NstADD, and harboring either wild-type cckA or cckA(L228P) or cckA(L228P) mutation back-crossed into a clean ∆nstA background [∆nstA cckA(L228P)-bc]. Cells, as indicated, were diluted five folds and spotted on media containing 0.5 mM vanillate. (D) Differential interference contrast (DIC) image of the suppressor mutant, ∆nstA cckA(L228P). Scale bar: 2 μm.