Interaction between sensor domain and histidine kinase domain of sensory histidine kinase in the two-component signaling system

2003 ◽  
Vol 96 (1) ◽  
pp. 173
Author(s):  
Hideyuki Kumita ◽  
Seiji Yamada ◽  
Hiro Nakamura ◽  
Yoshitsugu Shiro
Keyword(s):  
Histidine Kinase ◽  
Kinase Domain ◽  
Signaling System ◽  
Two Component

scholarly journals Feedback control of a two-component signaling system by an Fe-S-binding receiver domain

2019 ◽  
Author(s):  
Benjamin J. Stein ◽  
Aretha Fiebig ◽  
Sean Crosson
Keyword(s):  
Feedback Control ◽  
Histidine Kinase ◽  
Oxygen Sensor ◽  
Cell Physiology ◽  
Environmental Cues ◽  
Sensor Kinase ◽  
Signaling System ◽  
Receiver Domain ◽  
Two Component ◽  
Feedback Inhibitor

AbstractTwo-component signaling systems (TCSs) function to detect environmental cues and transduce this information into a change in transcription. In its simplest form, TCS-dependent regulation of transcription entails phosphoryl-transfer from a sensory histidine kinase to its cognate DNA-binding receiver protein. However, in certain cases, auxiliary proteins may modulate TCSs in response to secondary environmental cues. Caulobacter crescentus FixT is one such auxiliary regulator. FixT is composed of a single receiver domain and functions as a feedback inhibitor of the FixL-FixJ (FixLJ) TCS, which regulates the transcription of genes involved in adaptation to microaerobiosis. We sought to define the impact of fixT on Caulobacter cell physiology and to understand the molecular mechanism by which FixT represses FixLJ signaling. fixT deletion results in excess production of porphyrins and premature entry into stationary phase, demonstrating the importance of feedback inhibition of the FixLJ signaling system. Although FixT is a receiver domain, it does not affect dephosphorylation of the oxygen-sensor kinase FixL or phosphoryltransfer from FixL to its cognate receiver FixJ. Rather, FixT represses FixLJ signaling by inhibiting the FixL autophosphorylation reaction. We have further identified a 4-cysteine motif in Caulobacter FixT that binds an Fe-S cluster and protects the protein from degradation by the Lon protease. Our data support a model in which oxidation of this Fe-S cluster promotes degradation of FixT in vivo. This proteolytic mechanism facilitates clearance the of the FixT feedback inhibitor from the cell under normoxia and resets the FixLJ system for a future microaerobic signaling event.ImportanceTwo-component signal transduction systems (TCSs) are broadly conserved in the bacterial kingdom and generally contain two molecular components: a sensor histidine kinase and a receiver protein. Sensor histidine kinases alter their phosphorylation state in direct response to a physical or chemical cue, whereas receiver proteins “receive” the phosphoryl group from the kinase to regulate a change in cell physiology. We have discovered that a single-domain receiver protein, FixT, binds an Fe-S cluster and controls Caulobacter heme homeostasis though its function as a negative feedback regulator of the oxygen-sensor kinase, FixL. We provide evidence that the Fe-S cluster protects FixT from Lon-dependent proteolysis in the cell and endows FixT with the ability to function as a second, autonomous oxygen/redox sensor in the FixL-FixJ signaling pathway. This study introduces a novel mechanism of regulated TCS feedback control by an Fe-S-binding receiver domain.

scholarly journals Succinoglycan Production by Rhizobium meliloti Is Regulated through the ExoS-ChvI Two-Component Regulatory System

1998 ◽  
Vol 180 (1) ◽  
pp. 20-26 ◽  
Author(s):  
Hai-Ping Cheng ◽  
Graham C. Walker
Keyword(s):  
Histidine Kinase ◽  
Cytoplasmic Membrane ◽  
Rhizobium Meliloti ◽  
Response Regulator ◽  
Regulatory System ◽  
Kinase Domain ◽  
Cloning And Sequencing ◽  
System A ◽  
Two Component ◽  
Close Homolog

ABSTRACT The Rhizobium meliloti exoS gene is involved in regulating the production of succinoglycan, which plays a crucial role in the establishment of the symbiosis between R. melilotiRm1021 and its host plant, alfalfa. TheexoS96::Tn5 mutation causes the upregulation of the succinoglycan biosynthetic genes, thereby resulting in the overproduction of succinoglycan. Through cloning and sequencing, we found that the exoS gene is a close homolog of theAgrobacterium tumefaciens chvG gene, which has been proposed to encode the sensor protein of the ChvG-ChvI two-component regulatory system, a member of the EnvZ-OmpR family. Further analyses revealed the existence of a newly discovered A. tumefaciens chvI homolog located just upstream of the R. meliloti exoS gene. R. meliloti ChvI may serve as the response regulator of ExoS in a two-component regulatory system. By using ExoS-specific antibodies, it was found that the ExoS protein cofractionated with membrane proteins, suggesting that it is located in the cytoplasmic membrane. By using the same antibodies, it was shown that the exoS96::Tn5 allele encodes an N-terminal truncated derivative of ExoS. The cytoplasmic histidine kinase domain of ExoS was expressed in Escherichia coli and purified, as was the R. meliloti ChvI protein. The ChvI protein autophosphorylated in the presence of acetylphosphate, and the ExoS cytoplasmic domain fragment autophosphorylated at a histidine residue in the presence of ATP. The ChvI protein was phosphorylated in the presence of ATP only when the histidine kinase domain of ExoS was also present. We propose a model for regulation of succinoglycan production by R. meliloti through the ExoS-ChvI two-component regulatory system.

scholarly journals The Anaplasma phagocytophilum PleC Histidine Kinase and PleD Diguanylate Cyclase Two-Component System and Role of Cyclic Di-GMP in Host Cell Infection

2008 ◽  
Vol 191 (3) ◽  
pp. 693-700 ◽  
Author(s):  
Tzung-Huei Lai ◽  
Yumi Kumagai ◽  
Mamoru Hyodo ◽  
Yoshihiro Hayakawa ◽  
Yasuko Rikihisa
Keyword(s):  
Histidine Kinase ◽  
Anaplasma Phagocytophilum ◽  
Kinase Domain ◽  
Etiologic Agent ◽  
Diguanylate Cyclase ◽  
Response Regulators ◽  
Cell Infection ◽  
Granulocytic Anaplasmosis ◽  
Two Component

ABSTRACT Anaplasma phagocytophilum, the etiologic agent of human granulocytic anaplasmosis (HGA), has genes predicted to encode three sensor kinases, one of which is annotated PleC, and three response regulators, one of which is PleD. Prior to this study, the roles of PleC and PleD in the obligatory intracellular parasitism of A. phagocytophilum and their biochemical activities were unknown. The present study illustrates the relevance of these factors by demonstrating that both pleC and pleD were expressed in an HGA patient. During A. phagocytophilum development in human promyelocytic HL-60 cells, PleC and PleD were synchronously upregulated at the exponential growth stage and downregulated prior to extracellular release. A recombinant PleC kinase domain (rPleCHKD) has histidine kinase activity; no activity was observed when the conserved site of phosphorylation was replaced with alanine. A recombinant PleD (rPleD) has autokinase activity using phosphorylated rPleCHKD as the phosphoryl donor but not with two other recombinant histidine kinases. rPleCHKD could not serve as the phosphoryl donor for a mutant rPleD (with a conserved aspartic acid, the site of phosphorylation, replaced by alanine) or two other A. phagocytophilum recombinant response regulators. rPleD had diguanylate cyclase activity to generate cyclic (c) di-GMP from GTP in vitro. UV cross-linking of A. phagocytophilum lysate with c-di-[32P]GMP detected an ∼47-kDa endogenous protein, presumably c-di-GMP downstream receptor. A new hydrophobic c-di-GMP derivative, 2′-O-di(tert-butyldimethylsilyl)-c-di-GMP, inhibited A. phagocytophilum infection in HL-60 cells. Our results suggest that the two-component PleC-PleD system is a diguanylate cyclase and that a c-di-GMP-receptor complex regulates A. phagocytophilum intracellular infection.

scholarly journals Allosteric mechanism of signal transduction in the two-component system histidine kinase PhoQ

2021 ◽  
Author(s):  
Bruk Mensa ◽  
Nicholas F Polizzi ◽  
Kathleen S Molnar ◽  
Andrew M Natale ◽  
Thomas Lemmin ◽  
...  
Keyword(s):  
Histidine Kinase ◽  
Equilibrium Constants ◽  
Kinase Domain ◽  
Domain Model ◽  
Bistable System ◽  
E Coli ◽  
Allosteric Communication ◽  
Two Component ◽  
Cytoplasmic Kinase Domain ◽  
Semi Empirical

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 mutants distant from the sensor or catalytic site strongly influence PhoQ’s ligand-sensitivity as well as the magnitude and direction of the signal, endowing diverse signaling characteristics without need for epistasis. Data from 35 mutants are explained by a semi-empirical 3-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 favors the ‘off’ state; when coupled, they create a bistable system responsive to physiological [Mg2+]. Mutants alter signaling by locally modulating these intrinsic equilibrium constants and 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.

scholarly journals Pneumococcal HtrA Protease Mediates Inhibition of Competence by the CiaRH Two-Component Signaling System

2005 ◽  
Vol 187 (12) ◽  
pp. 3969-3979 ◽  
Author(s):  
M. E. Sebert ◽  
K. P. Patel ◽  
M. Plotnick ◽  
J. N. Weiser
Keyword(s):  
Histidine Kinase ◽  
Transformation Efficiency ◽  
Signaling System ◽  
Inhibitory Effects ◽  
Genetic Competence ◽  
Constitutive Activation ◽  
Protein Target ◽  
Protein Levels ◽  
Unknown Protein ◽  
Two Component

ABSTRACT Activation of the CiaRH two-component signaling system prevents the development of competence for genetic transformation in Streptococcus pneumoniae through a previously unknown mechanism. Earlier studies have shown that CiaRH controls the expression of htrA, which we show encodes a surface-expressed serine protease. We found that mutagenesis of the putative catalytic serine of HtrA, while not impacting the competence of a ciaRH + strain, restored a normal competence profile to a strain having a mutation that constitutively activates the CiaH histidine kinase. This result implies that activity of HtrA is necessary for the CiaRH system to inhibit competence. Consistent with this finding, recombinant HtrA (rHtrA) decreased the competence of pneumococcal cultures. The rHtrA-mediated decline in transformation efficiency could not be corrected with excess competence-stimulating peptide (CSP), suggesting that HtrA does not act through degradation of this signaling molecule. The inhibitory effects of rHtrA and activated CiaH, however, were largely overcome in a strain having constitutive activation of the competence pathway through a mutation in the cytoplasmic domain of the ComD histidine kinase. Although these results suggested that HtrA might act through degradation of the extracellular portion of the ComD receptor, Western immunoblots for ComD did not reveal changes in protein levels attributable to HtrA. We therefore postulate that HtrA may act on an unknown protein target that potentiates the activation of the ComDE system by CSP. These findings suggest a novel regulatory role for pneumococcal HtrA in modulating the activity of a two-component signaling system that controls the development of genetic competence.

scholarly journals Feedback Control of a Two-Component Signaling System by an Fe-S-Binding Receiver Domain

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Benjamin J. Stein ◽  
Aretha Fiebig ◽  
Sean Crosson
Keyword(s):  
Histidine Kinase ◽  
Oxygen Sensor ◽  
Cell Physiology ◽  
Phosphoryl Transfer ◽  
Environmental Cues ◽  
Sensor Kinase ◽  
Signaling System ◽  
Receiver Domain ◽  
Two Component ◽  
Feedback Inhibitor

ABSTRACT Two-component signaling systems (TCSs) function to detect environmental cues and transduce this information into a change in transcription. In its simplest form, TCS-dependent regulation of transcription entails phosphoryl-transfer from a sensory histidine kinase to its cognate DNA-binding receiver protein. However, in certain cases, auxiliary proteins may modulate TCSs in response to secondary environmental cues. Caulobacter crescentus FixT is one such auxiliary regulator. FixT is composed of a single receiver domain and functions as a feedback inhibitor of the FixL-FixJ (FixLJ) TCS, which regulates the transcription of genes involved in adaptation to microaerobiosis. We sought to define the impact of fixT on Caulobacter cell physiology and to understand the molecular mechanism by which FixT represses FixLJ signaling. fixT deletion results in excess production of porphyrins and premature entry into stationary phase, demonstrating the importance of feedback inhibition of the FixLJ signaling system. Although FixT is a receiver domain, it does not affect dephosphorylation of the oxygen sensor kinase FixL or phosphoryl-transfer from FixL to its cognate receiver FixJ. Rather, FixT represses FixLJ signaling by inhibiting the FixL autophosphorylation reaction. We have further identified a 4-cysteine motif in Caulobacter FixT that binds an Fe-S cluster and protects the protein from degradation by the Lon protease. Our data support a model in which the oxidation of this Fe-S cluster promotes the degradation of FixT in vivo. This proteolytic mechanism facilitates clearance of the FixT feedback inhibitor from the cell under normoxia and resets the FixLJ system for a future microaerobic signaling event. IMPORTANCE Two-component signal transduction systems (TCSs) are broadly conserved in the bacterial kingdom and generally contain two molecular components, a sensor histidine kinase and a receiver protein. Sensor histidine kinases alter their phosphorylation state in direct response to a physical or chemical cue, whereas receiver proteins “receive” the phosphoryl group from the kinase to regulate a change in cell physiology. We have discovered that a single-domain receiver protein, FixT, binds an Fe-S cluster and controls Caulobacter heme homeostasis though its function as a negative-feedback regulator of the oxygen sensor kinase FixL. We provide evidence that the Fe-S cluster protects FixT from Lon-dependent proteolysis in the cell and endows FixT with the ability to function as a second, autonomous oxygen/redox sensor in the FixL-FixJ signaling pathway. This study introduces a novel mechanism of regulated TCS feedback control by an Fe-S-binding receiver domain.

scholarly journals Comparative analysis of two paradigm bacteriophytochromes reveals opposite functionalities in two-component signaling

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Elina Multamäki ◽  
Rahul Nanekar ◽  
Dmitry Morozov ◽  
Topias Lievonen ◽  
David Golonka ◽  
...  
Keyword(s):  
Histidine Kinase ◽  
Deinococcus Radiodurans ◽  
Response Regulator ◽  
Red Light ◽  
Kinase Domain ◽  
Structural Level ◽  
Signaling Systems ◽  
Two Component ◽  
Cognate Response Regulator ◽  
Absorbing States

AbstractBacterial phytochrome photoreceptors usually belong to two-component signaling systems which transmit environmental stimuli to a response regulator through a histidine kinase domain. Phytochromes switch between red light-absorbing and far-red light-absorbing states. Despite exhibiting extensive structural responses during this transition, the model bacteriophytochrome from Deinococcus radiodurans (DrBphP) lacks detectable kinase activity. Here, we resolve this long-standing conundrum by comparatively analyzing the interactions and output activities of DrBphP and a bacteriophytochrome from Agrobacterium fabrum (Agp1). Whereas Agp1 acts as a conventional histidine kinase, we identify DrBphP as a light-sensitive phosphatase. While Agp1 binds its cognate response regulator only transiently, DrBphP does so strongly, which is rationalized at the structural level. Our data pinpoint two key residues affecting the balance between kinase and phosphatase activities, which immediately bears on photoreception and two-component signaling. The opposing output activities in two highly similar bacteriophytochromes suggest the use of light-controllable histidine kinases and phosphatases for optogenetics.

scholarly journals Allosteric mechanism of signal transduction in the two-component system histidine kinase PhoQ

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Bruk Mensa ◽  
Nicholas F Polizzi ◽  
Kathleen S Molnar ◽  
Andrew M Natale ◽  
Thomas Lemmin ◽  
...  
Keyword(s):  
Histidine Kinase ◽  
Equilibrium Constants ◽  
Kinase Domain ◽  
Domain Model ◽  
Bistable System ◽  
E Coli ◽  
Allosteric Communication ◽  
Two Component ◽  
Cytoplasmic Kinase Domain ◽  
Semi Empirical

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.

scholarly journals Illuminating a Phytochrome Paradigm – a Light-Activated Phosphatase in Two-Component Signaling Uncovered

2020 ◽  
Author(s):  
Elina Multamäki ◽  
Rahul Nanekar ◽  
Dmitry Morozov ◽  
Topias Lievonen ◽  
David Golonka ◽  
...  
Keyword(s):  
Histidine Kinase ◽  
Deinococcus Radiodurans ◽  
Response Regulator ◽  
Red Light ◽  
Kinase Domain ◽  
Structural Level ◽  
Signaling Systems ◽  
Two Component ◽  
Cognate Response Regulator ◽  
Absorbing States

ABSTRACTBacterial phytochrome photoreceptors usually belong to two-component signaling systems which transmit environmental stimuli to a response regulator through a histidine kinase domain. Phytochromes switch between red light-absorbing and far-red light-absorbing states. Despite exhibiting extensive structural responses during this transition, the model bacteriophytochrome from Deinococcus radiodurans (DrBphP) lacks detectable kinase activity. Here, we resolve this long-standing conundrum by comparatively analyzing the interactions and output activities of DrBphP and a bacteriophytochrome from Agrobacterium fabrum (AgP1). Whereas AgP1 acts as a conventional histidine kinase, we identify DrBphP as a light-sensitive phosphatase. While AgP1 binds its cognate response regulator only transiently, DrBphP does so strongly, which is rationalized at the structural level. Our data pinpoint two key residues affecting the balance between kinase and phosphatase activities, which immediately bears on photoreception and two-component signaling. The opposing output activities in two highly similar bacteriophytochromes inform the use of light-controllable histidine kinases and phosphatases for optogenetics.

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