1
|
Schubert C, Unden G. Fumarate, a central electron acceptor for Enterobacteriaceae beyond fumarate respiration and energy conservation. Adv Microb Physiol 2023; 82:267-299. [PMID: 36948656 DOI: 10.1016/bs.ampbs.2022.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
C4-dicarboxylates (C4-DCs) such as fumarate, l-malate and l-aspartate are key substrates for Enterobacteria such as Escherichia coli or Salmonella typhimurium during anaerobic growth. In general, C4-DCs are oxidants during biosynthesis, e.g., of pyrimidine or heme, acceptors for redox balancing, a high-quality nitrogen source (l-aspartate) and electron acceptor for fumarate respiration. Fumarate reduction is required for efficient colonization of the murine intestine, even though the colon contains only small amounts of C4-DCs. However, fumarate can be produced endogenously by central metabolism, allowing autonomous production of an electron acceptor for biosynthesis and redox balancing. Bacteria possess a complex set of transporters for the uptake (DctA), antiport (DcuA, DcuB, TtdT) and excretion (DcuC) of C4-DCs. DctA and DcuB exert regulatory functions and link transport to metabolic control through interaction with regulatory proteins. The sensor kinase DcuS of the C4-DC two-component system DcuS-DcuR forms complexes with DctA (aerobic) or DcuB (anaerobic), representing the functional state of the sensor. Moreover, EIIAGlc from the glucose phospho-transferase system binds to DctA and presumably inhibits C4-DC uptake. Overall, the function of fumarate as an oxidant in biosynthesis and redox balancing explains the pivotal role of fumarate reductase for intestinal colonization, while the role of fumarate in energy conservation (fumarate respiration) is of minor importance.
Collapse
Affiliation(s)
- Christopher Schubert
- Institute for Molecular Physiology (IMP), Microbiology and Biotechnology; Johannes Gutenberg-University, Mainz, Germany; Institute of Microbiology, ETH Zurich, Zurich, Switzerland.
| | - Gottfried Unden
- Institute for Molecular Physiology (IMP), Microbiology and Biotechnology; Johannes Gutenberg-University, Mainz, Germany.
| |
Collapse
|
2
|
The role of sensory kinase proteins in two-component signal transduction. Biochem Soc Trans 2022; 50:1859-1873. [DOI: 10.1042/bst20220848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/02/2022] [Accepted: 11/08/2022] [Indexed: 11/19/2022]
Abstract
Two-component systems (TCSs) are modular signaling circuits that regulate diverse aspects of microbial physiology in response to environmental cues. These molecular circuits comprise a sensor histidine kinase (HK) protein that contains a conserved histidine residue, and an effector response regulator (RR) protein with a conserved aspartate residue. HKs play a major role in bacterial signaling, since they perceive specific stimuli, transmit the message across the cytoplasmic membrane, and catalyze their own phosphorylation, and the trans-phosphorylation and dephosphorylation of their cognate response regulator. The molecular mechanisms by which HKs co-ordinate these functions have been extensively analyzed by genetic, biochemical, and structural approaches. Here, we describe the most common modular architectures found in bacterial HKs, and address the operation mode of the individual functional domains. Finally, we discuss the use of these signaling proteins as drug targets or as sensing devices in whole-cell biosensors with medical and biotechnological applications.
Collapse
|
3
|
Tight Complex Formation of the Fumarate Sensing DcuS-DcuR Two-Component System at the Membrane and Target Promoter Search by Free DcuR Diffusion. mSphere 2022; 7:e0023522. [PMID: 35862816 PMCID: PMC9429925 DOI: 10.1128/msphere.00235-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Signaling of two-component systems by phosphoryl transfer requires interaction of the sensor kinase with the response regulator. Interaction of the C4-dicarboxylate-responsive and membrane-integral sensor kinase DcuS with the response regulator DcuR was studied. In vitro, the cytoplasmic part of DcuS (PASC-Kin) was employed. Stable complexes were formed, when either DcuS or DcuR were phosphorylated (Kd 22 ± 11 and 28 ± 7 nM, respectively). The unphosphorylated proteins produced a more labile complex (Kd 1380 ± 395 nM). Bacterial two-hybrid studies confirm interaction of DcuR with DcuS (and PASC-Kin) in vivo. The absolute contents of DcuR (197-979 pmol mg−1 protein) in the bacteria exceeded those of DcuS by more than 1 order of magnitude. According to the Kd values, DcuS exists in complex, with phosphorylated but also unphosphorylated DcuR. In live cell imaging, the predominantly freely diffusing DcuR becomes markedly less mobile after phosphorylation and activation of DcuS by fumarate. Portions of the low mobility fraction accumulated at the cell poles, the preferred location of DcuS, and other portions within the cell, representing phosphorylated DcuR bound to promoters. In the model, acitvation of DcuS increases the affinity toward DcuR, leading to DcuS-P × DcuR formation and phosphorylation of DcuR. The complex is stable enough for phosphate-transfer, but labile enough to allow exchange between DcuR from the cytosol and DcuR-P of the complex. Released DcuR-P diffuses to target promoters and binds. Uncomplexed DcuR-P in the cytosol binds to nonactivated DcuS and becomes dephosphorylated. The lower affinity between DcuR and DcuS avoids blocking of DcuS and allows rapid exchange of DcuR. IMPORTANCE Complex formation of membrane-bound sensor kinases with the response regulators represents an inherent step of signaling from the membrane to the promoters on the DNA. In the C4-dicarboxylate-sensing DcuS-DcuR two-component system, complex formation is strengthened by activation (phosphorylation) in vitro and in vivo, with trapping of the response regulator DcuR at the membrane. Single-molecule tracking of DcuR in the bacterial cell demonstrates two populations of DcuR with decreased mobility in the bacteria after activation: one at the membrane, but a second in the cytosol, likely representing DNA-bound DcuR. The data suggest a model with binding of DcuR to DcuS-P for phosphorylation, and of DcuR-P to DcuS for dephosphorylation, allowing rapid adaptation of the DcuR phosphorylation state. DcuR-P is released and transferred to DNA by 3D diffusion.
Collapse
|
4
|
C4-dicarboxylates as growth substrates and signaling molecules for commensal and pathogenic enteric bacteria in mammalian intestine. J Bacteriol 2022; 204:e0054521. [PMID: 34978458 DOI: 10.1128/jb.00545-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The C4-dicarboxylates (C4-DC) L-aspartate and L-malate have been identified as playing an important role in the colonization of mammalian intestine by enteric bacteria, such as Escherichia coli and Salmonella Typhimurium, and succinate as a signaling molecule for host-enteric bacteria interaction. Thus, endogenous and exogenous fumarate respiration and related functions are required for efficient initial growth of the bacteria. L-aspartate represents a major substrate for fumarate respiration in the intestine and a high-quality substrate for nitrogen assimilation. During nitrogen assimilation, DcuA catalyzes an L-aspartate/fumarate antiport and serves as a nitrogen shuttle for the net uptake of ammonium only, whereas DcuB acts as a redox shuttle that catalyzes the L-malate/succinate antiport during fumarate respiration. The C4-DC two-component system DcuS-DcuR is active in the intestine and responds to intestinal C4-DC levels. Moreover, in macrophages and in mice, succinate is a signal that promotes virulence and survival of S. Tm and pathogenic E. coli. On the other hand, intestinal succinate is an important signaling molecule for the host and activates response and protective programs. Therefore, C4-DCs play a major role in supporting colonization of enteric bacteria and as signaling molecules for the adaptation of host physiology.
Collapse
|
5
|
Mensa B, Polizzi NF, Molnar KS, Natale AM, Lemmin T, DeGrado WF. Allosteric mechanism of signal transduction in the two-component system histidine kinase PhoQ. eLife 2021; 10:73336. [PMID: 34904568 PMCID: PMC8719878 DOI: 10.7554/elife.73336] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 12/13/2021] [Indexed: 12/05/2022] Open
Abstract
Transmembrane signaling proteins couple extracytosolic sensors to cytosolic effectors. Here, we examine how binding of Mg2+ to the sensor domain of an E. coli two component histidine kinase (HK), PhoQ, modulates its cytoplasmic kinase domain. We use cysteine-crosslinking and reporter-gene assays to simultaneously and independently probe the signaling state of PhoQ’s sensor and autokinase domains in a set of over 30 mutants. Strikingly, conservative single-site mutations distant from the sensor or catalytic site strongly influence PhoQ’s ligand-sensitivity as well as the magnitude and direction of the signal. Data from 35 mutants are explained by a semi-empirical three-domain model in which the sensor, intervening HAMP, and catalytic domains can adopt kinase-promoting or inhibiting conformations that are in allosteric communication. The catalytic and sensor domains intrinsically favor a constitutively ‘kinase-on’ conformation, while the HAMP domain favors the ‘off’ state; when coupled, they create a bistable system responsive to physiological concentrations of Mg2+. Mutations alter signaling by locally modulating domain intrinsic equilibrium constants and interdomain couplings. Our model suggests signals transmit via interdomain allostery rather than propagation of a single concerted conformational change, explaining the diversity of signaling structural transitions observed in individual HK domains.
Collapse
Affiliation(s)
- Bruk Mensa
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States.,Cardiovascular Research Institute, University of California, San Francisco, San Francisco, United States.,Chemistry and Chemical Biology PhD program, University of California, San Francisco, San Francisco, United States
| | - Nicholas F Polizzi
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States
| | | | - Andrew M Natale
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States.,Cardiovascular Research Institute, University of California, San Francisco, San Francisco, United States.,Biophysics PhD program, University of California, San Francisco, San Francisco, United States
| | - Thomas Lemmin
- Euler Institute, Università della Svizzera Italiana, Lugano, Switzerland
| | - William F DeGrado
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States.,Cardiovascular Research Institute, University of California, San Francisco, San Francisco, United States
| |
Collapse
|
6
|
Diversity in Sensing and Signaling of Bacterial Sensor Histidine Kinases. Biomolecules 2021; 11:biom11101524. [PMID: 34680156 PMCID: PMC8534201 DOI: 10.3390/biom11101524] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/13/2021] [Accepted: 10/13/2021] [Indexed: 11/17/2022] Open
Abstract
Two-component signal transduction systems (TCSs) are widely conserved in bacteria to respond to and adapt to the changing environment. Since TCSs are also involved in controlling the expression of virulence, biofilm formation, quorum sensing, and antimicrobial resistance in pathogens, they serve as candidates for novel drug targets. TCSs consist of a sensor histidine kinase (HK) and its cognate response regulator (RR). Upon perception of a signal, HKs autophosphorylate their conserved histidine residues, followed by phosphotransfer to their partner RRs. The phosphorylated RRs mostly function as transcriptional regulators and control the expression of genes necessary for stress response. HKs sense their specific signals not only in their extracytoplasmic sensor domain but also in their cytoplasmic and transmembrane domains. The signals are sensed either directly or indirectly via cofactors and accessory proteins. Accumulating evidence shows that a single HK can sense and respond to multiple signals in different domains. The underlying molecular mechanisms of how HK activity is controlled by these signals have been extensively studied both biochemically and structurally. In this article, we introduce the wide diversity of signal perception in different domains of HKs, together with their recently clarified structures and molecular mechanisms.
Collapse
|
7
|
Stopp M, Steinmetz PA, Unden G. Properties of transmembrane helix TM1 of the DcuS sensor kinase of Escherichia coli, the stator for TM2 piston signaling. Biol Chem 2021; 402:1239-1246. [PMID: 34355547 DOI: 10.1515/hsz-2021-0254] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 07/05/2021] [Indexed: 11/15/2022]
Abstract
The sensor kinase DcuS of Escherichia coli perceives extracellular fumarate by a periplasmic PASP sensor domain. Transmembrane (TM) helix TM2, present as TM2-TM2' homo-dimer, transmits fumarate activation in a piston-slide across the membrane. The second TM helix of DcuS, TM1, is known to lack piston movement. Structural and functional properties of TM1 were analyzed. Oxidative Cys-crosslinking (CL) revealed homo-dimerization of TM1 over the complete membrane, but only the central part showed α-helical +3/+4 spacing of the CL maxima. The GALLEX bacterial two-hybrid system indicates TM1/TM1' interaction, and the presence of a TM1-TM1' homo-dimer is suggested. The peripheral TM1 regions presented CL in a spacing atypical for α-helical arrangement. On the periplasmic side the deviation extended over 11 AA residues (V32-S42) between the α-helical part of TM1 and the onset of PASP. In the V32-S42 region, CL efficiency decreased in the presence of fumarate. Therefore, TM1 exists as a homo-dimer with α-helical arrangement in the central membrane region, and non-α-helical arrangement in the connector to PASP. The fumarate induced structural response in the V32-S42 region is suggested to represent a structural adaptation to the shift of TM2 in the TM1-TM1'/TM2-TM2' four-helical bundle.
Collapse
Affiliation(s)
- Marius Stopp
- Microbiology and Wine Research, Institute for Molecular Physiology, Johannes Gutenberg University Mainz, BZ II, Hanns-Dieter-Hüsch-Weg 17, D-55128Mainz, Germany
| | - Philipp A Steinmetz
- Microbiology and Wine Research, Institute for Molecular Physiology, Johannes Gutenberg University Mainz, BZ II, Hanns-Dieter-Hüsch-Weg 17, D-55128Mainz, Germany
| | - Gottfried Unden
- Microbiology and Wine Research, Institute for Molecular Physiology, Johannes Gutenberg University Mainz, BZ II, Hanns-Dieter-Hüsch-Weg 17, D-55128Mainz, Germany
| |
Collapse
|
8
|
Stopp M, Schubert C, Unden G. Conversion of the Sensor Kinase DcuS to the Fumarate Sensitive State by Interaction of the Bifunctional Transporter DctA at the TM2/PAS C-Linker Region. Microorganisms 2021; 9:microorganisms9071397. [PMID: 34203512 PMCID: PMC8307970 DOI: 10.3390/microorganisms9071397] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/13/2021] [Accepted: 06/21/2021] [Indexed: 11/16/2022] Open
Abstract
The membrane-bound C4-dicarboxylate (C4DC) sensor kinase DcuS of Escherichia coli typically forms a protein complex with the C4DC transporter DctA. The DctA × DcuS complex is able to respond to C4DCs, whereas DcuS without DctA is in the permanent ON state. In DctA, the C-terminal helix 8b (H8b) serves as the site for interaction with DcuS. Here the interaction site in DcuS and the related structural and functional adaptation in DcuS were determined. The Linker connecting transmembrane helix 2 (TM2) and the cytosolic PASC (Per-ARNT-SIM) domain of DcuS, was identified as the major site for interaction with DctA-H8b by in vivo interaction studies. The Linker is known to convert the piston-type transmembrane signaling of TM2 to a tilting motion which relies on a resolution of the Linker-Linker’ homodimer in the presence of C4DCs. Absence of DctA caused decreased cross-linking in the Linker, as identified by oxidative Cys-cross-linking. This response resembled structurally and functionally that of fumarate activation in the DctA × DcuS complex. Overall, formation of the DctA × DcuS complex is based on the interaction of the DcuS Linker with DctA H8b; the interaction is required to set DcuS in the C4DC-responsive state by stabilizing the linker-linker’ homodimer in DcuS. This work identifies DctA as a structural co-regulator of DcuS sensor kinase.
Collapse
|
9
|
Signal Recognition Particle Suppressor Screening Reveals the Regulation of Membrane Protein Targeting by the Translation Rate. mBio 2021; 12:mBio.02373-20. [PMID: 33436432 PMCID: PMC7844537 DOI: 10.1128/mbio.02373-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The signal recognition particle (SRP) is conserved in all living organisms, and it cotranslationally delivers proteins to the inner membrane or endoplasmic reticulum. Recently, SRP loss was found not to be lethal in either the eukaryote Saccharomyces cerevisiae or the prokaryote Streptococcus mutans In Escherichia coli, the role of SRP in mediating inner membrane protein (IMP) targeting has long been studied. However, the essentiality of SRP remains a controversial topic, partly hindered by the lack of strains in which SRP is completely absent. Here we show that the SRP was nonessential in E. coli by suppressor screening. We identified two classes of extragenic suppressors-two translation initiation factors and a ribosomal protein-all of which are involved in translation initiation. The translation rate and inner membrane proteomic analyses were combined to define the mechanism that compensates for the lack of SRP. The primary factor that contributes to the efficiency of IMP targeting is the extension of the time window for targeting by pausing the initiation of translation, which further reduces translation initiation and elongation rates. Furthermore, we found that easily predictable features in the nascent chain determine the specificity of protein targeting. Our results show why the loss of the SRP pathway does not lead to lethality. We report a new paradigm in which the time delay in translation initiation is beneficial during protein targeting in the absence of SRP.IMPORTANCE Inner membrane proteins (IMPs) are cotranslationally inserted into the inner membrane or endoplasmic reticulum by the signal recognition particle (SRP). Generally, the deletion of SRP can result in protein targeting defects in Escherichia coli Suppressor screening for loss of SRP reveals that pausing at the translation start site is likely to be critical in allowing IMP targeting and avoiding aggregation. In this work, we found for the first time that SRP is nonessential in E. coli The time delay in initiation is different from the previous mechanism that only slows down the elongation rate. It not only maximizes the opportunity for untranslated ribosomes to be near the inner membrane but also extends the time window for targeting translating ribosomes by decreasing the speed of translation. We anticipate that our work will be a starting point for a more delicate regulatory mechanism of protein targeting.
Collapse
|
10
|
Stopp M, Steinmetz PA, Schubert C, Griesinger C, Schneider D, Unden G. Transmembrane signaling and cytoplasmic signal conversion by dimeric transmembrane helix 2 and a linker domain of the DcuS sensor kinase. J Biol Chem 2020; 296:100148. [PMID: 33277358 PMCID: PMC7857512 DOI: 10.1074/jbc.ra120.015999] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/30/2020] [Accepted: 12/04/2020] [Indexed: 01/16/2023] Open
Abstract
Transmembrane (TM) signaling is a key process of membrane-bound sensor kinases. The C4-dicarboxylate (fumarate) responsive sensor kinase DcuS of Escherichia coli is anchored by TM helices TM1 and TM2 in the membrane. Signal transmission across the membrane relies on the piston-type movement of the periplasmic part of TM2. To define the role of TM2 in TM signaling, we use oxidative Cys cross-linking to demonstrate that TM2 extends over the full distance of the membrane and forms a stable TM homodimer in both the inactive and fumarate-activated state of DcuS. An S186xxxGxxxG194 motif is required for the stability and function of the TM2 homodimer. The TM2 helix further extends on the periplasmic side into the α6-helix of the sensory PASP domain and on the cytoplasmic side into the α1-helix of PASC. PASC has to transmit the signal to the C-terminal kinase domain. A helical linker on the cytoplasmic side connecting TM2 with PASC contains an LxxxLxxxL sequence. The dimeric state of the linker was relieved during fumarate activation of DcuS, indicating structural rearrangements in the linker. Thus, DcuS contains a long α-helical structure reaching from the sensory PASP (α6) domain across the membrane to α1(PASC). Taken together, the results suggest piston-type TM signaling by the TM2 homodimer from PASP across the full TM region, whereas the fumarate-destabilized linker dimer converts the signal on the cytoplasmic side for PASC and kinase regulation.
Collapse
Affiliation(s)
- Marius Stopp
- Microbiology and Wine Research, Institute for Molecular Physiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Philipp Aloysius Steinmetz
- Microbiology and Wine Research, Institute for Molecular Physiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Christopher Schubert
- Microbiology and Wine Research, Institute for Molecular Physiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Christian Griesinger
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Gottingen, Germany
| | - Dirk Schneider
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Gottfried Unden
- Microbiology and Wine Research, Institute for Molecular Physiology, Johannes Gutenberg University Mainz, Mainz, Germany.
| |
Collapse
|
11
|
Koh A, Gibbon MJ, Van der Kamp MW, Pudney CR, Gebhard S. Conformation control of the histidine kinase BceS of Bacillus subtilis by its cognate ABC-transporter facilitates need-based activation of antibiotic resistance. Mol Microbiol 2020; 115:157-174. [PMID: 32955745 DOI: 10.1111/mmi.14607] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/09/2020] [Accepted: 09/09/2020] [Indexed: 12/15/2022]
Abstract
Bacteria closely control gene expression to ensure optimal physiological responses to their environment. Such careful gene expression can minimize the fitness cost associated with antibiotic resistance. We previously described a novel regulatory logic in Bacillus subtilis enabling the cell to directly monitor its need for detoxification. This cost-effective strategy is achieved via a two-component regulatory system (BceRS) working in a sensory complex with an ABC-transporter (BceAB), together acting as a flux-sensor where signaling is proportional to transport activity. How this is realized at the molecular level has remained unknown. Using experimentation and computation we here show that the histidine kinase is activated by piston-like displacements in the membrane, which are converted to helical rotations in the catalytic core via an intervening HAMP-like domain. Intriguingly, the transporter was not only required for kinase activation, but also to actively maintain the kinase in its inactive state in the absence of antibiotics. Such coupling of kinase activity to that of the transporter ensures the complete control required for transport flux-dependent signaling. Moreover, we show that the transporter likely conserves energy by signaling with sub-maximal sensitivity. These results provide the first mechanistic insights into transport flux-dependent signaling, a unique strategy for energy-efficient decision making.
Collapse
Affiliation(s)
- Alan Koh
- Department of Biology and Biochemistry, University of Bath, Bath, UK.,Milner Centre for Evolution, University of Bath, Bath, UK
| | - Marjorie J Gibbon
- Department of Biology and Biochemistry, University of Bath, Bath, UK.,Milner Centre for Evolution, University of Bath, Bath, UK
| | | | | | - Susanne Gebhard
- Department of Biology and Biochemistry, University of Bath, Bath, UK.,Milner Centre for Evolution, University of Bath, Bath, UK
| |
Collapse
|
12
|
Phosphoregulated orthogonal signal transduction in mammalian cells. Nat Commun 2020; 11:3085. [PMID: 32555187 PMCID: PMC7303213 DOI: 10.1038/s41467-020-16895-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 05/28/2020] [Indexed: 12/17/2022] Open
Abstract
Orthogonal tools for controlling protein function by post-translational modifications open up new possibilities for protein circuit engineering in synthetic biology. Phosphoregulation is a key mechanism of signal processing in all kingdoms of life, but tools to control the involved processes are very limited. Here, we repurpose components of bacterial two-component systems (TCSs) for chemically induced phosphotransfer in mammalian cells. TCSs are the most abundant multi-component signal-processing units in bacteria, but are not found in the animal kingdom. The presented phosphoregulated orthogonal signal transduction (POST) system uses induced nanobody dimerization to regulate the trans-autophosphorylation activity of engineered histidine kinases. Engineered response regulators use the phosphohistidine residue as a substrate to autophosphorylate an aspartate residue, inducing their own homodimerization. We verify this approach by demonstrating control of gene expression with engineered, dimerization-dependent transcription factors and propose a phosphoregulated relay system of protein dimerization as a basic building block for next-generation protein circuits. Phosphoregulation is a key mechanism of signal processing. Here the authors build a phosphoregulated relay system in mammalian cells for orthogonal signal transduction.
Collapse
|
13
|
Gushchin I, Orekhov P, Melnikov I, Polovinkin V, Yuzhakova A, Gordeliy V. Sensor Histidine Kinase NarQ Activates via Helical Rotation, Diagonal Scissoring, and Eventually Piston-Like Shifts. Int J Mol Sci 2020; 21:E3110. [PMID: 32354084 PMCID: PMC7247690 DOI: 10.3390/ijms21093110] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 04/19/2020] [Accepted: 04/24/2020] [Indexed: 12/20/2022] Open
Abstract
Membrane-embedded sensor histidine kinases (HKs) and chemoreceptors are used ubiquitously by bacteria and archaea to percept the environment, and are often crucial for their survival and pathogenicity. The proteins can transmit the signal from the sensor domain to the catalytic kinase domain reliably over the span of several hundreds of angstroms, and regulate the activity of the cognate response regulator proteins, with which they form two-component signaling systems (TCSs). Several mechanisms of transmembrane signal transduction in TCS receptors have been proposed, dubbed (swinging) piston, helical rotation, and diagonal scissoring. Yet, despite decades of studies, there is no consensus on whether these mechanisms are common for all TCS receptors. Here, we extend our previous work on Escherichia coli nitrate/nitrite sensor kinase NarQ. We determined a crystallographic structure of the sensor-TM-HAMP fragment of the R50S mutant, which, unexpectedly, was found in a ligand-bound-like conformation, despite an inability to bind nitrate. Subsequently, we reanalyzed the structures of the ligand-free and ligand-bound NarQ and NarX sensor domains, and conducted extensive molecular dynamics simulations of ligand-free and ligand-bound wild type and mutated NarQ. Based on the data, we show that binding of nitrate to NarQ causes, first and foremost, helical rotation and diagonal scissoring of the α-helices at the core of the sensor domain. These conformational changes are accompanied by a subtle piston-like motion, which is amplified by a switch in the secondary structure of the linker between the sensor and TM domains. We conclude that helical rotation, diagonal scissoring, and piston are simply different degrees of freedom in coiled-coil proteins and are not mutually exclusive in NarQ, and likely in other nitrate sensors and TCS proteins as well.
Collapse
Affiliation(s)
- Ivan Gushchin
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia
| | - Philipp Orekhov
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia
- Institute of Personalized Medicine, Sechenov University, 119146 Moscow, Russia
| | - Igor Melnikov
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, 52428 Jülich, Germany
- European Synchrotron Radiation Facility, 38000 Grenoble, France
| | - Vitaly Polovinkin
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, 52428 Jülich, Germany
- Institut de Biologie Structurale J.-P. Ebel, Université Grenoble Alpes-CEA-CNRS, 38000 Grenoble, France
| | - Anastasia Yuzhakova
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Valentin Gordeliy
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, 52428 Jülich, Germany
- Institut de Biologie Structurale J.-P. Ebel, Université Grenoble Alpes-CEA-CNRS, 38000 Grenoble, France
- JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, 52428 Jülich, Germany
| |
Collapse
|
14
|
Trajtenberg F, Buschiazzo A. Protein Dynamics in Phosphoryl-Transfer Signaling Mediated by Two-Component Systems. Methods Mol Biol 2020; 2077:1-18. [PMID: 31707648 DOI: 10.1007/978-1-4939-9884-5_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The ability to perceive the environment, an essential attribute in living organisms, is linked to the evolution of signaling proteins that recognize specific signals and execute predetermined responses. Such proteins constitute concerted systems that can be as simple as a unique protein, able to recognize a ligand and exert a phenotypic change, or extremely complex pathways engaging dozens of different proteins which act in coordination with feedback loops and signal modulation. To understand how cells sense their surroundings and mount specific adaptive responses, we need to decipher the molecular workings of signal recognition, internalization, transfer, and conversion into chemical changes inside the cell. Protein allostery and dynamics play a central role. Here, we review recent progress on the study of two-component systems, important signaling machineries of prokaryotes and lower eukaryotes. Such systems implicate a sensory histidine kinase and a separate response regulator protein. Both components exploit protein flexibility to effect specific conformational rearrangements, modulating protein-protein interactions, and ultimately transmitting information accurately. Recent work has revealed how histidine kinases switch between discrete functional states according to the presence or absence of the signal, shifting key amino acid positions that define their catalytic activity. In concert with the cognate response regulator's allosteric changes, the phosphoryl-transfer flow during the signaling process is exquisitely fine-tuned for proper specificity, efficiency and directionality.
Collapse
Affiliation(s)
- Felipe Trajtenberg
- Laboratory of Molecular and Structural Microbiology, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Alejandro Buschiazzo
- Laboratory of Molecular and Structural Microbiology, Institut Pasteur de Montevideo, Montevideo, Uruguay.
- Département de Microbiologie, Institut Pasteur, Paris, France.
| |
Collapse
|
15
|
Jacob-Dubuisson F, Mechaly A, Betton JM, Antoine R. Structural insights into the signalling mechanisms of two-component systems. Nat Rev Microbiol 2019; 16:585-593. [PMID: 30008469 DOI: 10.1038/s41579-018-0055-7] [Citation(s) in RCA: 139] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Two-component systems reprogramme diverse aspects of microbial physiology in response to environmental cues. Canonical systems are composed of a transmembrane sensor histidine kinase and its cognate response regulator. They catalyse three reactions: autophosphorylation of the histidine kinase, transfer of the phosphoryl group to the regulator and dephosphorylation of the phosphoregulator. Elucidating signal transduction between sensor and output domains is highly challenging given the size, flexibility and dynamics of histidine kinases. However, recent structural work has provided snapshots of the catalytic mechanisms of the three enzymatic reactions and described the conformation and dynamics of the enzymatic moiety in the kinase-competent and phosphatase-competent states. Insight into signalling mechanisms across the membrane is also starting to emerge from new crystal structures encompassing both sensor and transducer domains of sensor histidine kinases. In this Progress article, we highlight such important advances towards understanding at the molecular level the signal transduction mechanisms mediated by these fascinating molecular machines.
Collapse
Affiliation(s)
- Françoise Jacob-Dubuisson
- Université de Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204 - Center for Infection and Immunity of Lille, Lille, France.
| | - Ariel Mechaly
- Institut Pasteur, Plateforme de Cristallographie, CNRS-UMR3528, Paris, France
| | - Jean-Michel Betton
- Institut Pasteur, Unité de Microbiologie Structurale, CNRS-UMR3528, Paris, France
| | - Rudy Antoine
- Université de Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204 - Center for Infection and Immunity of Lille, Lille, France
| |
Collapse
|
16
|
Cellular Concentrations of the Transporters DctA and DcuB and the Sensor DcuS of Escherichia coli and the Contributions of Free and Complexed DcuS to Transcriptional Regulation by DcuR. J Bacteriol 2018; 200:JB.00612-17. [PMID: 29203472 DOI: 10.1128/jb.00612-17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 11/27/2017] [Indexed: 11/20/2022] Open
Abstract
In Escherichia coli, the catabolism of C4-dicarboxylates is regulated by the DcuS-DcuR two-component system. The functional state of the sensor kinase DcuS is controlled by C4-dicarboxylates (like fumarate) and complexation with the C4-dicarboxylate transporters DctA and DcuB, respectively. Free DcuS (DcuSF) is known to be constantly active even in the absence of fumarate, whereas the DcuB-DcuS and DctA-DcuS complexes require fumarate for activation. To elucidate the impact of the transporters on the functional state of DcuS and the concentrations of DcuSF and DcuB-DcuS (or DctA-DcuS), the absolute levels of DcuS, DcuB, and DctA were determined in aerobically or anaerobically grown cells by mass spectrometry. DcuS was present at a constant very low level (10 to 20 molecules DcuS/cell), whereas the levels of DcuB and DctA were higher (minimum, 200 molecules/cell) and further increased with fumarate (12.7- and 2.7-fold, respectively). Relating DcuS and DcuB contents with the functional state of DcuS allowed an estimation of the proportions of DcuS in the free (DcuSF) and the complexed (DcuB-DcuS) states. Unexpectedly, DcuSF levels were always low (<2% of total DcuS), ruling out earlier models that show DcuSF as the major species under noninducing conditions. In the absence of fumarate, when DcuSF is responsible for basal dcuB expression, up to 8% of the maximal DcuB levels are formed. These suffice for DcuB-DcuS complex formation and basal transport activity. In the presence of fumarate (>100 μM), the DcuB-DcuS complex drives the majority of dcuB expression and is thus responsible for induction.IMPORTANCE Two-component systems (TCS) are major devices for sensing by bacteria and adaptation to environmental cues. Membrane-bound sensor kinases of TCS often use accessory proteins of unknown function. The DcuS-DcuR TCS responds to C4-dicarboxylates and requires formation of the complex of DcuS with C4-dicarboxylate transporters DctA or DcuB. Free DcuS (DcuSF) is constitutively active in autophosphorylation and was supposed to have a major role under specific conditions. Here, absolute concentrations of DcuS, DcuB, and DctA were determined under activating and nonactivating conditions by mass spectrometry. The relationship of their absolute contents to the functional state of DcuS revealed their contribution to the control of DcuS-DcuR in vivo, which was not accessible by other approaches, leading to a revision of previous models.
Collapse
|
17
|
Gushchin I, Gordeliy V. Transmembrane Signal Transduction in Two-Component Systems: Piston, Scissoring, or Helical Rotation? Bioessays 2017; 40. [PMID: 29280502 DOI: 10.1002/bies.201700197] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 11/30/2017] [Indexed: 11/10/2022]
Abstract
Allosteric and transmembrane (TM) signaling are among the major questions of structural biology. Here, we review and discuss signal transduction in four-helical TM bundles, focusing on histidine kinases and chemoreceptors found in two-component systems. Previously, piston, scissors, and helical rotation have been proposed as the mechanisms of TM signaling. We discuss theoretically possible conformational changes and examine the available experimental data, including the recent crystallographic structures of nitrate/nitrite sensor histidine kinase NarQ and phototaxis system NpSRII:NpHtrII. We show that TM helices can flex at multiple points and argue that the various conformational changes are not mutually exclusive, and often are observed concomitantly, throughout the TM domain or in its part. The piston and scissoring motions are the most prominent motions in the structures, but more research is needed for definitive conclusions.
Collapse
Affiliation(s)
- Ivan Gushchin
- Moscow Institute of Physics and Technology, 141700, Dolgoprudniy, Russia
| | - Valentin Gordeliy
- Moscow Institute of Physics and Technology, 141700, Dolgoprudniy, Russia.,Université Grenoble Alpes, CEA, CNRS, IBS, F-38000, Grenoble, France.,Institute of Complex Systems (ICS), ICS-6: Structural Biochemistry, Research Centre Jülich, 52425, Jülich, Germany
| |
Collapse
|
18
|
Lesne E, Dupré E, Locht C, Antoine R, Jacob-Dubuisson F. Conformational Changes of an Interdomain Linker Mediate Mechanical Signal Transmission in Sensor Kinase BvgS. J Bacteriol 2017; 199:e00114-17. [PMID: 28507245 PMCID: PMC5573084 DOI: 10.1128/jb.00114-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 05/08/2017] [Indexed: 11/20/2022] Open
Abstract
The whooping cough agent, Bordetella pertussis, controls the expression of its large virulence regulon in a coordinated manner through the two-component system BvgAS. BvgS is a dimeric, multidomain sensor kinase. Each monomer comprises, in succession, tandem periplasmic Venus flytrap (VFT) domains, a transmembrane segment, a cytoplasmic Per-Arnt-Sim (PAS) domain, a kinase module, and additional phosphorelay domains. BvgS shifts between kinase and phosphatase modes of activity in response to chemical modulators that modify the clamshell motions of the VFT domains. We have shown previously that this regulation involves a shift between distinct states of conformation and dynamics of the two-helix coiled-coil linker preceding the enzymatic module. In this work, we determined the mechanism of signal transduction across the membrane via a first linker, which connects the VFT and PAS domains of BvgS, using extensive cysteine cross-linking analyses and other approaches. Modulator perception by the periplasmic domains appears to trigger a small, symmetrical motion of the transmembrane segments toward the periplasm, causing rearrangements of the noncanonical cytoplasmic coiled coil that follows. As a consequence, the interface of the PAS domains is modified, which affects the second linker and eventually causes the shift of enzymatic activity. The major features of this first linker are well conserved among BvgS homologs, indicating that the mechanism of signal transduction unveiled here is likely to be generally relevant for this family of sensor kinases.IMPORTANCEBordetella pertussis produces virulence factors coordinately regulated by the two-component system BvgAS. BvgS is a sensor kinase, and BvgA is a response regulator that activates gene transcription when phosphorylated by BvgS. Sensor kinases homologous to BvgS are also found in other pathogens. Our goal is to decipher the mechanisms of BvgS signaling, since these sensor kinases may represent new targets for antibacterial agents. Signal perception by the sensor domains of BvgS triggers small motions of the helical linker region underneath. The protein domain that follows this linker undergoes a large conformational change that amplifies the initial signal, causing a shift of activity from kinase to phosphatase. Because BvgS homologs harbor similar regions, these signaling mechanisms are likely to apply generally to that family of sensor kinases.
Collapse
Affiliation(s)
- Elodie Lesne
- Université Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL, Centre d'Infection et d'Immunité de Lille, Lille, France
| | - Elian Dupré
- Université Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL, Centre d'Infection et d'Immunité de Lille, Lille, France
| | - Camille Locht
- Université Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL, Centre d'Infection et d'Immunité de Lille, Lille, France
| | - Rudy Antoine
- Université Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL, Centre d'Infection et d'Immunité de Lille, Lille, France
| | - Françoise Jacob-Dubuisson
- Université Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL, Centre d'Infection et d'Immunité de Lille, Lille, France
| |
Collapse
|
19
|
Sensory domain contraction in histidine kinase CitA triggers transmembrane signaling in the membrane-bound sensor. Proc Natl Acad Sci U S A 2017; 114:3115-3120. [PMID: 28265100 DOI: 10.1073/pnas.1620286114] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacteria use membrane-integral sensor histidine kinases (HK) to perceive stimuli and transduce signals from the environment to the cytosol. Information on how the signal is transmitted across the membrane by HKs is still scarce. Combining both liquid- and solid-state NMR, we demonstrate that structural rearrangements in the extracytoplasmic, citrate-sensing Per-Arnt-Sim (PAS) domain of HK CitA are identical for the isolated domain in solution and in a longer construct containing the membrane-embedded HK and lacking only the kinase core. We show that upon citrate binding, the PAS domain contracts, resulting in a shortening of the C-terminal β-strand. We demonstrate that this contraction of the PAS domain, which is well characterized for the isolated domain, is the signal transmitted to the transmembrane (TM) helices in a CitA construct in liposomes. Putting the extracytoplasmic PAS domain into context of the membrane-embedded CitA construct slows down citrate-binding kinetics by at least a factor of 60, confirming that TM helix motions are linked to the citrate-binding event. Our results are confirmation of a hallmark of the HK signal transduction mechanism with atomic resolution on a full-length construct lacking only the kinase core domain.
Collapse
|
20
|
Piepenbreier H, Fritz G, Gebhard S. Transporters as information processors in bacterial signalling pathways. Mol Microbiol 2017; 104:1-15. [DOI: 10.1111/mmi.13633] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Hannah Piepenbreier
- LOEWE Center for Synthetic Microbiology; Philipps-University Marburg; Germany
| | - Georg Fritz
- LOEWE Center for Synthetic Microbiology; Philipps-University Marburg; Germany
| | - Susanne Gebhard
- Milner Centre for Evolution, Department of Biology and Biochemistry; University of Bath; UK
| |
Collapse
|
21
|
Wörner S, Strecker A, Monzel C, Zeltner M, Witan J, Ebert-Jung A, Unden G. Conversion of the sensor kinase DcuS of Escherichia coli of the DcuB/DcuS sensor complex to the C 4 -dicarboxylate responsive form by the transporter DcuB. Environ Microbiol 2016; 18:4920-4930. [PMID: 27318186 DOI: 10.1111/1462-2920.13418] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Accepted: 06/02/2016] [Indexed: 12/18/2022]
Abstract
The sensor kinase DcuS of Escherichia coli co-operates under aerobic conditions with the C4 -dicarboxylate transporter DctA to form the DctA/DcuS sensor complex. Under anaerobic conditions C4 -dicarboxylate transport in fumarate respiration is catalyzed by C4 -dicarboxylate/fumarate antiporter DcuB. (i) DcuB interacted with DcuS as demonstrated by a bacterial two-hybrid system (BACTH) and by co-chromatography of the solubilized membrane-proteins (mHPINE assay). (ii) In the DcuB/DcuS complex only DcuS served as the sensor since mutations in the substrate site of DcuS changed substrate specificity of sensing, and substrates maleate or 3-nitropropionate induced DcuS response without affecting the fumarate site of DcuB. (iii) The half-maximal concentration for induction of DcuS by fumarate (1 to 2 mM) and the corresponding Km for transport (50 µM) differ by a factor of 20 to 40. Therefore, the fumarate sites are different in transport and sensing. (iv) Increasing levels of DcuB converted DcuS from the permanent ON (DcuB deficient) state to the fumarate responsive form. Overall, the data show that DcuS and DcuB form a DcuB/DcuS complex representing the C4 -dicarboxylate responsive form, and that the sensory site of the complex is located in DcuS whereas DcuB is required for converting DcuS to the sensory competent state.
Collapse
Affiliation(s)
- Sebastian Wörner
- Institute for Microbiology and Wine Research, Johannes Gutenberg-University, Mainz, Germany
| | - Alexander Strecker
- Institute for Microbiology and Wine Research, Johannes Gutenberg-University, Mainz, Germany
| | - Christian Monzel
- Institute for Microbiology and Wine Research, Johannes Gutenberg-University, Mainz, Germany
| | - Matthias Zeltner
- Institute for Microbiology and Wine Research, Johannes Gutenberg-University, Mainz, Germany
| | - Julian Witan
- Institute for Microbiology and Wine Research, Johannes Gutenberg-University, Mainz, Germany
| | - Andrea Ebert-Jung
- Institute for Microbiology and Wine Research, Johannes Gutenberg-University, Mainz, Germany
| | - Gottfried Unden
- Institute for Microbiology and Wine Research, Johannes Gutenberg-University, Mainz, Germany
| |
Collapse
|
22
|
Unden G, Strecker A, Kleefeld A, Kim OB. C4-Dicarboxylate Utilization in Aerobic and Anaerobic Growth. EcoSal Plus 2016; 7. [PMID: 27415771 DOI: 10.1128/ecosalplus.esp-0021-2015] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Indexed: 06/06/2023]
Abstract
C4-dicarboxylates and the C4-dicarboxylic amino acid l-aspartate support aerobic and anaerobic growth of Escherichia coli and related bacteria. In aerobic growth, succinate, fumarate, D- and L-malate, L-aspartate, and L-tartrate are metabolized by the citric acid cycle and associated reactions. Because of the interruption of the citric acid cycle under anaerobic conditions, anaerobic metabolism of C4-dicarboxylates depends on fumarate reduction to succinate (fumarate respiration). In some related bacteria (e.g., Klebsiella), utilization of C4-dicarboxylates, such as tartrate, is independent of fumarate respiration and uses a Na+-dependent membrane-bound oxaloacetate decarboxylase. Uptake of the C4-dicarboxylates into the bacteria (and anaerobic export of succinate) is achieved under aerobic and anaerobic conditions by different sets of secondary transporters. Expression of the genes for C4-dicarboxylate metabolism is induced in the presence of external C4-dicarboxylates by the membrane-bound DcuS-DcuR two-component system. Noncommon C4-dicarboxylates like l-tartrate or D-malate are perceived by cytoplasmic one-component sensors/transcriptional regulators. This article describes the pathways of aerobic and anaerobic C4-dicarboxylate metabolism and their regulation. The citric acid cycle, fumarate respiration, and fumarate reductase are covered in other articles and discussed here only in the context of C4-dicarboxylate metabolism. Recent aspects of C4-dicarboxylate metabolism like transport, sensing, and regulation will be treated in more detail. This article is an updated version of an article published in 2004 in EcoSal Plus. The update includes new literature, but, in particular, the sections on the metabolism of noncommon C4-dicarboxylates and their regulation, on the DcuS-DcuR regulatory system, and on succinate production by engineered E. coli are largely revised or new.
Collapse
Affiliation(s)
- Gottfried Unden
- Institute for Microbiology und Wine Research, Johannes Gutenberg-University, 55099 Mainz, Germany
| | - Alexander Strecker
- Institute for Microbiology und Wine Research, Johannes Gutenberg-University, 55099 Mainz, Germany
| | - Alexandra Kleefeld
- Institute for Microbiology und Wine Research, Johannes Gutenberg-University, 55099 Mainz, Germany
| | - Ok Bin Kim
- Department of Life Sciences, Ewha Womans University, 120-750 Seoul, Korea
| |
Collapse
|
23
|
Heininger A, Yusuf R, Lawrence RJ, Draheim RR. Identification of transmembrane helix 1 (TM1) surfaces important for EnvZ dimerisation and signal output. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1868-75. [PMID: 27155567 DOI: 10.1016/j.bbamem.2016.05.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 04/12/2016] [Accepted: 05/03/2016] [Indexed: 02/06/2023]
Abstract
The Escherichia coli sensor kinase EnvZ modulates porin expression in response to various stimuli, including extracellular osmolarity, the presence of procaine and interaction with an accessory protein, MzrA. Two major outer membrane porins, OmpF and OmpC, act as passive diffusion-limited pores that allow compounds, including certain classes of antibiotics such as β-lactams and fluoroquinolones, to enter the bacterial cell. Even though the mechanisms by which EnvZ detects and processes the presence of various stimuli are a fundamental component of microbial physiology, they are not yet fully understood. Here, we assess the role of TM1 during signal transduction in response to the presence of extracellular osmolarity. Various mechanisms of transmembrane communication have been proposed including rotation of individual helices within the transmembrane domain, dynamic movement of the membrane-distal portion of the cytoplasmic domain and regulated intra-protein unfolding. To assess these possibilities, we have created a library of single-Cys-containing EnvZ proteins in order to facilitate sulfhydryl-reactivity experimentation. Our results demonstrate that the major TM1-TM1' interface falls along a single surface consisting of residue positions 19, 23, 26, 30 and 34. In addition, we show that Cys substitutions within the N- and C-terminal regions of TM1 result in drastic changes to EnvZ signal output. Finally, we demonstrate that core residues within TM1 are responsible for both TM1 dimerisation and maintenance of steady-state signal output. Overall, our results suggest that no major rearrangement of the TM1-TM1' interface occurs during transmembrane communication in response to extracellular osmolarity. We conclude by discussing these results within the frameworks of several proposed models for transmembrane communication.
Collapse
Affiliation(s)
- Annika Heininger
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, D-60438 Frankfurt, Germany.
| | - Rahmi Yusuf
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth PO1 2DT, England, UK.
| | - Robert J Lawrence
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth PO1 2DT, England, UK.
| | - Roger R Draheim
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth PO1 2DT, England, UK; Institute of Biomedical and Biomolecular Science, University of Portsmouth, Portsmouth PO1 2DT, England, UK.
| |
Collapse
|
24
|
Unden G, Wörner S, Monzel C. Cooperation of Secondary Transporters and Sensor Kinases in Transmembrane Signalling: The DctA/DcuS and DcuB/DcuS Sensor Complexes of Escherichia coli. Adv Microb Physiol 2016; 68:139-67. [PMID: 27134023 DOI: 10.1016/bs.ampbs.2016.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Many membrane-bound sensor kinases require accessory proteins for function. The review describes functional control of membrane-bound sensors by transporters. The C4-dicarboxylate sensor kinase DcuS requires the aerobic or anaerobic C4-dicarboxylate transporters DctA or DcuB, respectively, for function and forms DctA/DcuS or DcuB/DcuS sensor complexes. Free DcuS is in the permanent (ligand independent) ON state. The DctA/DcuS and DcuB/DcuS complexes, on the other hand, control expression in response to C4-dicarboxylates. In DctA/DcuS, helix 8b of DctA and the PASC domain of DcuS are involved in interaction. The stimulus is perceived by the extracytoplasmic sensor domain (PASP) of DcuS. The signal is transmitted across the membrane by a piston-type movement of TM2 of DcuS which appears to be pulled (by analogy to the homologous citrate sensor CitA) by compaction of PASP after C4-dicarboxylate binding. In the cytoplasm, the signal is perceived by the PASC domain of DcuS. PASC inhibits together with DctA the kinase domain of DcuS which is released after C4-dicarboxylate binding. DcuS exhibits two modes for regulating expression of target genes. At higher C4-dicarboxylate levels, DcuS is part of the DctA/DcuS complex and in the C4-dicarboxylate-responsive form which stimulates expression of target genes in response to the concentration of the C4-dicarboxylates (catabolic use of C4-dicarboxylates, mode I regulation). At limiting C4-dicarboxylate concentrations (≤0.05mM), expression of DctA drops and free DcuS appears. Free DcuS is in the permanent ON state (mode II regulation) and stimulates low level (C4-dicarboxylate independent) DctA synthesis for DctA/DcuS complex formation and anabolic C4-dicarboxylate uptake.
Collapse
Affiliation(s)
- G Unden
- Institute for Microbiology and Wine Research, University of Mainz, Mainz, Germany.
| | - S Wörner
- Institute for Microbiology and Wine Research, University of Mainz, Mainz, Germany
| | - C Monzel
- Institute for Microbiology and Wine Research, University of Mainz, Mainz, Germany
| |
Collapse
|