Activation of Bacterial Porin Gene Expression by a Chimeric Signal Transducer in Response to Aspartate

Utsumi, Ryutaro; Brissette, Renée; Rampersaud, Arfaan; Forst, Steven; Oosawa, Kenji; Inouye, Masayori

doi:10.1126/science.2476847

Cited by 200 publications

(179 citation statements)

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“…The phenotypes of different Tar-EnvZ hybrid receptors in the present paper (Tez5, -6, -7, -8, and -9) as well as those of Taz1 and Taz2-1 in the previous works (9,12) suggest that both the Tar linker and the EnvZ linker need to be intact for fulfilling their function, and specific interactions between helix I and helix II in the linker is important for signal transduction. Particularly, helix II may serve as an effector element within the linker for further signal propagation, as it may form a long coiled-coil structure together with helix I of domain A of EnvZ based on LEARNCOIL prediction.…”

Section: Discussionmentioning

confidence: 98%

“…The resultant Taz (12) and Trz (13) are able to respond to aspartate and ribose in the medium, respectively, to activate ompC-lacZ in a concentration-dependent manner, suggesting that the chemoreceptors and EnvZ share a common signal transduction mechanism. Similar chimeric receptors have also been constructed using the periplasmic and transmembrane domain of Tar and the cytoplasmic domain of the human insulin receptor (14) or the periplasmic domain of the histidine kinase NarX and the cytoplasmic domain of Tar (15), further supporting a notion that there is a common mechanism widely used by signal transduction across the membrane in both prokaryotes and eukaryotes.…”

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confidence: 99%

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Analysis of the Role of the EnvZ Linker Region in Signal Transduction Using a Chimeric Tar/EnvZ Receptor Protein, Tez1

Zhu

Inouye

2003

Journal of Biological Chemistry

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Tez1 is a chimeric protein in which the periplasmic and transmembrane domains of Tar, a chemosensor, are fused to the cytoplasmic catalytic domain of EnvZ, an osmosensing histidine kinase, through the EnvZ linker. Unlike Taz1 (a similar hybrid with the Tar linker), Tez1 could not respond to Tar ligand, aspartate, whereas single Ala insertion at the transmembrane/linker junction, as seen in Tez1A1, restored the aspartate-regulatable phenotype. Analysis of the Ala insertion site requirement and the nature of the insertion residue on the phenotype of Tez1 indicated that a junction region between the transmembrane domain and the predicted helix I in the linker is critical to signal transduction. Random mutagenesis revealed that P185Q mutation in the Tez1 linker restored the aspartate-regulatable phenotype. Substitution mutations at Pro-185 further demonstrated that specific residues are required at this site for an aspartate response. None of the hybrid receptors constructed with different Tar/EnvZ fusion sites in the linker could respond to aspartate, suggesting that specific interactions between the two predicted helices in the linker are important for the linker function. In addition, a mutation (F220D) known to cause an OmpC c phenotype in EnvZ resulted in similar OmpC c phenotypes in both Tez1A1 and Tez1, indicating the importance of the predicted helix II in signal propagation. Together, we propose that the N-terminal junction region modulates the alignment between the two helices in the linker upon signal input. In turn helix II propagates the resultant conformational signal into the downstream catalytic domain of EnvZ to regulate its bifunctional enzymatic activities.EnvZ, a histidine kinase osmosensor, locates on the inner membrane of Escherichia coli. It is composed of a periplasmic domain, transmembrane domains, and a cytoplasmic domain (1, 2). The cytoplasmic domain has been further dissected into three subdomains, the linker region, domain A, and domain B, in which the latter two form the catalytic core of EnvZ, harboring both kinase and phosphatase functions (3). NMR structures of both domain A and domain B have been solved (4, 5). Biochemical analysis has revealed that the domain A of the EnvZ is responsible for the dimerization, phosphotransfer and phosphatase functions, and domain B binds ATP and catalytically assists the enzymatic function of domain A (3, 6). The spatial arrangement between these two domains appears to be crucial for the modulation of EnvZ enzymatic activities (6). Previous studies suggest that EnvZ senses the extracellular osmolarity changes, transmits the signal through its transmembrane domain, and then modulates the kinase/phosphatase ratio of the cytoplasmic catalytic domain, which controls the cellular concentration of phosphorylated OmpR to mediate the reciprocal expression of the two major outer membrane porin proteins OmpF and OmpC (2, 7-11).Although the exact ligand for EnvZ remains unknown, two kinds of chimeric receptors have been constructed in which the periplasmic an...

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Section: Discussionmentioning

confidence: 98%

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confidence: 99%

Analysis of the Role of the EnvZ Linker Region in Signal Transduction Using a Chimeric Tar/EnvZ Receptor Protein, Tez1

Zhu

Inouye

2003

Journal of Biological Chemistry

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“…To gain insight into transmembrane signal transduction mechanisms of EnvZ, several groups have constructed aspartate-and ribose-responsive chimaeric proteins consisting of the N-terminal periplasmic and transmembrane domains of the Tar or Trg chemoreceptors respectively, and the cytoplasmic catalytic domain of EnvZ [11,12]. Studies on these chimaeric proteins [13,14], combined with mutagenesis analysis [15,16], have shown that the transmembrane, as well as the linker helices, plays a role in signal propagation.…”

Section: Introductionmentioning

confidence: 99%

Structural characterization of Escherichia coli sensor histidine kinase EnvZ: the periplasmic C-terminal core domain is critical for homodimerization

Khorchid

Inouye

Ikura

2004

Biochemical Journal

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Escherichia coli EnvZ is a membrane sensor histidine kinase that plays a pivotal role in cell adaptation to changes in extracellular osmolarity. Although the cytoplasmic histidine kinase domain of EnvZ has been extensively studied, both biochemically and structurally, little is known about the structure of its periplasmic domain, which has been implicated in the mechanism underlying its osmosensing function. In the present study, we report the biochemical and biophysical characterization of the periplasmic region of EnvZ (Ala 38 -Arg 162 ). This region was found to form a dimer in solution, and to consist of two well-defined domains: an N-terminal α-helical domain and a C-terminal core domain (Glu 83 -Arg 162 ) containing both α-helical and β-sheet secondary structures. Our pull-down assays and analytical ultracentrifugation analysis revealed that dimerization of the periplasmic region is highly sensitive to the presence of CHAPS, but relatively insensitive to salt concentration, thus suggesting the significance of hydrophobic interactions between the homodimeric subunits. Periplasmic homodimerization is mediated predominantly by the C-terminal core domain, while a regulatory function may be attributed mainly to the N-terminal α-helical domain, whose mutations have been shown previously to produce a high-osmolarity phenotype.

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“…(2) Adapting the ability to rewire twocomponent pathways for synthetic biology efforts. Methods for rationally redirecting information flow within bacteria combined with advances in engineering histidine kinases with desired sensory capabilities [49][50][51] will enable the construction of sophisticated new signaling circuits.…”

Section: Discussionmentioning

confidence: 99%

Determinants of specificity in two-component signal transduction

Podgornaia

Laub

2013

Current Opinion in Microbiology

129

133

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Maintaining the faithful flow of information through signal transduction pathways is critical to the survival and proliferation of organisms. This problem is particularly challenging as many signaling proteins are part of large, paralogous families that are highly similar at the sequence and structural levels, increasing the risk of unwanted cross-talk. To detect environmental signals and process information, bacteria rely heavily on two-component signaling systems comprised of sensor histidine kinases and their cognate response regulators. Although most species encode dozens of these signaling pathways, there is relatively little cross-talk, indicating that individual pathways are well insulated and highly specific. Here, we review the molecular mechanisms that enforce this specificity. Further, we highlight recent studies that have revealed how these mechanisms evolve to accommodate the introduction of new pathways by gene duplication.3

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Activation of Bacterial Porin Gene Expression by a Chimeric Signal Transducer in Response to Aspartate

Cited by 200 publications

References 23 publications

Analysis of the Role of the EnvZ Linker Region in Signal Transduction Using a Chimeric Tar/EnvZ Receptor Protein, Tez1

Analysis of the Role of the EnvZ Linker Region in Signal Transduction Using a Chimeric Tar/EnvZ Receptor Protein, Tez1

Structural characterization of Escherichia coli sensor histidine kinase EnvZ: the periplasmic C-terminal core domain is critical for homodimerization

Determinants of specificity in two-component signal transduction

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