A monomeric histidine kinase derived from EnvZ, an <i>Escherichia coli</i> osmosensor

Dutta, Rinku; Kurokawa, H.; Ikura, Mitsuhiko; Inouye, Masayori

doi:10.1046/j.1365-2958.2000.01837.x

Cited by 38 publications

(40 citation statements)

References 27 publications

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“…GAF, as well as the DHp subdomain of HPK, may also contribute to CikA dimerization as do the GAF domains of an adenylyl cyclase whose structure has been solved (Qin et al, 2000;Martinez et al, 2005). Thus, the lack of complementation of TH-CikA∆G, and loss of kinase activity, may result from loss of dimerization activity, as natural HPKs are not known to function as monomers (Qin et al, 2000).…”

Section: Model For Function Of Cikamentioning

confidence: 99%

“…Thus, the lack of complementation of TH-CikA∆G, and loss of kinase activity, may result from loss of dimerization activity, as natural HPKs are not known to function as monomers (Qin et al, 2000). Alternatively, the importance of GAF may lie with its binding of an unidentified ligand and regulatory aspects associated with bound and unbound changes in conformation of the protein, or through physical interaction with protein partners of its own.…”

Section: Model For Function Of Cikamentioning

confidence: 99%

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The pseudo‐receiver domain of CikA regulates the cyanobacterial circadian input pathway

Zhang

Dong

Golden

2006

Molecular Microbiology

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SummaryCikA (circadian input kinase) is a component of the cyanobacterial circadian clock that aids in synchronizing the endogenous oscillator with the external environment. cikA mutants of the prokaryotic circadian model organism Synechococcus elongatus PCC 7942 fail to reset the phase of the circadian rhythm of gene expression after an environmental time cue, and also exhibit reduced amplitude and shortened period of circadian oscillation. CikA has histidine protein kinase (HPK) activity that is modulated in vitro by GAF and pseudo -receiver (PsR) domains. Here we show that the PsR domain negatively regulates HPK activity in vivo and also serves as an interaction module to dock CikA at a specific subcellular location. Phenotypes conferred by alleles that encode CikA variants showed that all domains except the featureless Nterminus are required for CikA function. Overexpression of all alleles that encode the PsR domain, whether or not the HPK is functional, caused a dominant arrhythmic phenotype, whereas overexpressed variants that lack PsR did not. Subcellular localization of intact CikA identified a polar focus whereas a variant without PsR showed uniform distribution in the cell, consistent with a model in which PsR mediates interaction with other input pathway components.

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Section: Model For Function Of Cikamentioning

confidence: 99%

Section: Model For Function Of Cikamentioning

confidence: 99%

The pseudo‐receiver domain of CikA regulates the cyanobacterial circadian input pathway

Zhang

Dong

Golden

2006

Molecular Microbiology

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“…GST fusion proteins and control samples (0.5-5 l) were analyzed on hydrophobic (H4) chips, whereas WhiB3 (his) was analyzed on immobilized metal affinity capture (IMAC-3) chips. In vitro interaction between GST-RpoV and immobilized WhiB3 (his) was performed essentially as described (22) except that PBS with 0.2% Triton X-100 was used as incubation buffer. A saturated solution of ␣-cyano-4-hydroxycinnamic acid in 50% acetonitrile and 0.5% trifluoroacetic acid or ferulic acid in 50% isopropanol and 0.5% trifluoroacetic was used as matrix.…”

Section: Seldi-tofmentioning

confidence: 99%

Mycobacterium tuberculosis WhiB3 interacts with RpoV to affect host survival but is dispensable for in vivo growth

Steyn

Collins

Hondalus

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

223

210

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Previous work established that the principal sigma factor (RpoV) of virulent Mycobacterium bovis, a member of the Mycobacterium tuberculosis complex, restores virulence to an attenuated strain containing a point mutation (Arg-5153 His) in the 4.2 domain of RpoV. We used the 4.2 domain of RpoV as bait in a yeast two-hybrid screen of an M. tuberculosis H37Rv library and identified a putative transcription factor, WhiB3, which selectively interacts with the 4.2 domain of RpoV in virulent strains but not with the mutated (Arg-5153 His) allele. Infection of mice and guinea pigs with a M. tuberculosis H37Rv whiB3 deletion mutant strain showed that whiB3 is not necessary for in vivo bacterial replication in either animal model. In contrast, an M. bovis whiB3 deletion mutant was completely attenuated for growth in guinea pigs. However, we found that immunocompetent mice infected with the M. tuberculosis H37Rv whiB3 mutant strain had significantly longer mean survival times as compared with mice challenged with wild-type M. tuberculosis. Remarkably, the bacterial organ burdens of both mutant and wild-type infected mice were identical during the acute and persistent phases of infection. Our results imply that M. tuberculosis replication per se is not a sufficient condition for virulence in vivo. They also indicate a different role for M. bovis and M. tuberculosis whiB3 genes in pathogenesis generated in different animal models. We propose that M. tuberculosis WhiB3 functions as a transcription factor regulating genes that influence the immune response of the host.T he increased susceptibility of HIV-infected individuals and the emergence of multidrug-resistant strains of Mycobacterium tuberculosis (MTB) results in the death of 2-3 million people each year (1) and underscores the urgency of deciphering the molecular mechanisms of virulence of this pathogen. The highly variable protective efficacy of Mycobacterium bovis bacillus Calmette-Guérin in adults (0-80%; ref. 2) emphasizes the urgency for developing second-generation antituberculosis antimicrobial agents and vaccines. With these aims in mind, research stimulated by the advances in mycobacterial genetics (3, 4) has led to the identification of several genes that have been implicated in virulence (5-12).MTB requires sophisticated genetic mechanisms to recognize appropriate environmental signals and to convey this information to the transcriptional apparatus of the organism. The activation of bacterial sigma factors to regulate gene expression is an effective response mechanism that enables pathogens to respond instantly to a multitude of environmental signals. Bacterial 70 -type sigma factors are composed of four major regions, called regions 1, 2, 3 and 4 (13). Region 4 is subdivided further into sub regions 4.1 and 4.2; the latter is known to interact with the Ϫ35 region of promoters (13) and other transcription factors. Mutations in or close to the helix-turn-helix (HTH) motif in region 4.2 can result in either positive or negative effects on activation by transcri...

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“…(lanes [25][26][27][28] with all the other experiments], the reason for which is not known at present.…”

Section: Resultsmentioning

confidence: 85%

“…The association of OmpR and EnvZc has been observed by the Ni-nitrilotriacetic acid resin-binding method, either by using His-tagged EnvZc (H. Park & M.I., unpublished data) or His-tagged OmpR (25). Recently, we found that native PAGE is another approach to detecting the interaction between OmpR and EnvZc.…”

Section: Resultsmentioning

confidence: 99%

The critical role of DNA in the equilibrium between OmpR and phosphorylated OmpR mediated by EnvZ in Escherichiacoli

Qin¹

2001

Proceedings of the National Academy of Sciences

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Escherichia coli modulates its porin expression through a histidine kinase, EnvZ, and its cognate response regulator, OmpR. EnvZ is a bifunctional enzyme that possesses both OmpR kinase and phosphorylated OmpR (OmpR-P) phosphatase activities and thus controls the cellular level of OmpR-P. In an in vitro-assay system, the addition of OmpR to the reaction mixture consisting of the cytoplasmic domain of EnvZ (EnvZc) and ATP produces a barely detectable amount of OmpR-P because of the dual activities of EnvZ. Here we report that DNA fragments containing the upstream promoter regions of the porin genes (ompF and ompC) can shift the equilibrium between OmpR and OmpR-P dramatically toward OmpR-P. Among the four reactions occurring in the mixture, only the EnvZ phosphatase activity was inhibited severely by the specific DNA, in contrast to the previous report by Kenney and her associates that The autophosphorylation of EnvZc and the phosphotransfer from phosphorylated EnvZc to OmpR were not affected by DNA, whereas the autodephosphorylation of OmpR-P was inhibited slightly. We propose that the apparent inhibitory effect of DNA on the EnvZ phosphatase function is caused by sequestrating OmpR-P from the reaction as a result of OmpR-P binding to DNA.

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A monomeric histidine kinase derived from EnvZ, an Escherichia coli osmosensor

Cited by 38 publications

References 27 publications

The pseudo‐receiver domain of CikA regulates the cyanobacterial circadian input pathway

The pseudo‐receiver domain of CikA regulates the cyanobacterial circadian input pathway

Mycobacterium tuberculosis WhiB3 interacts with RpoV to affect host survival but is dispensable for in vivo growth

The critical role of DNA in the equilibrium between OmpR and phosphorylated OmpR mediated by EnvZ in Escherichiacoli

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