scholarly journals Cognate sensor kinase‐independent activation of Mycobacterium tuberculosis response regulator DevR (DosR) by acetyl phosphate: implications in anti‐mycobacterial drug design

2019 ◽  
Vol 111 (5) ◽  
pp. 1182-1194 ◽  
Author(s):  
Saurabh Sharma ◽  
Priyanka Kumari ◽  
Atul Vashist ◽  
Chanchal Kumar ◽  
Malobi Nandi ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Drug Design ◽  
Response Regulator ◽  
Sensor Kinase ◽  
Acetyl Phosphate

scholarly journals Mycobacterium tuberculosis DosS binds H2S through its Fe3+ heme iron to regulate the Dos dormancy regulon

2021 ◽  
Author(s):  
Ritesh R Sevalkar ◽  
Joel N Glasgow ◽  
Martin Pettinati ◽  
Marcelo A Martin ◽  
Vineel P Reddy ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Response Regulator ◽  
Heme Iron ◽  
Sensor Kinase ◽  
New Paradigm ◽  
Heme Pocket ◽  
Expression Of Genes ◽  
Sensor Kinases ◽  
Dynamics Simulations ◽  
Autokinase Activity

Mycobacterium tuberculosis (Mtb) senses and responds to host-derived gasotransmitters NO and CO via heme-containing sensor kinases DosS and DosT and the response regulator DosR. Hydrogen sulfide (H2S) is an important signaling molecule in mammals, but its role in Mtb physiology is unclear. We have previously shown that exogenous H2S can modulate expression of genes in the Dos dormancy regulon via an unknown mechanism(s). Here, we tested the hypothesis that Mtb senses and responds to H2S via the DosS/T/R system. Using UV-Vis and EPR spectroscopy, we show that H2S binds directly to the ferric (Fe3+) heme of DosS (KD = 5.64 uM) but not the ferrous (Fe2+) form. No interaction with DosT was detected. Thus, the mechanism by which DosS senses H2S is different from that for sensing NO and CO, which bind only the ferrous forms of DosS and DosT. Steered Molecular Dynamics simulations show that H2S, and not the charged HS- species, can enter the DosS heme pocket. We also show that H2S increases DosS autokinase activity and subsequent phosphorylation of DosR, and H2S-mediated increases in Dos regulon gene expression is lost in Mtb lacking DosS. Finally, we demonstrate that physiological levels of H2S in macrophages can induce Dos regulon genes via DosS. Overall, these data reveal a novel mechanism whereby Mtb senses and responds to a third host gasotransmitter, H2S, via DosS-Fe3+. These findings highlight the remarkable plasticity of DosS and establish a new paradigm for how bacteria can sense multiple gasotransmitters through a single heme sensor kinase.

scholarly journals Mycobacterium tuberculosis sensor kinase DosS modulates the autophagosome in a DosR-independent manner

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Uma S. Gautam ◽  
Smriti Mehra ◽  
Priyanka Kumari ◽  
Xavier Alvarez ◽  
Tianhua Niu ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Life Cycle ◽  
Nitrogen Metabolism ◽  
Response Regulator ◽  
Infection Process ◽  
Molybdenum Cofactor ◽  
Sensor Kinase ◽  
Independent Manner ◽  
Tnf Α ◽  
Hypoxia Adaptation

Abstract Dormancy is a key characteristic of the intracellular life-cycle of Mtb. The importance of sensor kinase DosS in mycobacteria are attributed in part to our current findings that DosS is required for both persistence and full virulence of Mtb. Here we show that DosS is also required for optimal replication in macrophages and involved in the suppression of TNF-α and autophagy pathways. Silencing of these pathways during the infection process restored full virulence in MtbΔdosS mutant. Notably, a mutant of the response regulator DosR did not exhibit the attenuation in macrophages, suggesting that DosS can function independently of DosR. We identified four DosS targets in Mtb genome; Rv0440, Rv2859c, Rv0994, and Rv0260c. These genes encode functions related to hypoxia adaptation, which are not directly controlled by DosR, e.g., protein recycling and chaperoning, biosynthesis of molybdenum cofactor and nitrogen metabolism. Our results strongly suggest a DosR-independent role for DosS in Mtb.

scholarly journals Inhibiting Mycobacterium tuberculosis DosRST Signaling by Targeting Response Regulator DNA Binding and Sensor Kinase Heme

2019 ◽  
Vol 15 (1) ◽  
pp. 52-62 ◽  
Author(s):  
Huiqing Zheng ◽  
John T. Williams ◽  
Bilal Aleiwi ◽  
Edmund Ellsworth ◽  
Robert B. Abramovitch
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Dna Binding ◽  
Response Regulator ◽  
Sensor Kinase

scholarly journals Phosphatase-defective DevS sensor kinase mutants permit constitutive expression of DevR-regulated dormancy genes in Mycobacterium tuberculosis

2020 ◽  
Vol 477 (9) ◽  
pp. 1669-1682
Author(s):  
Priyanka Kumari ◽  
Sudhir Kumar ◽  
Kohinoor Kaur ◽  
Umesh Datta Gupta ◽  
Sameer Suresh Bhagyawant ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Response Regulator ◽  
Constitutive Expression ◽  
Culture Conditions ◽  
Negative Control ◽  
Adaptation To Hypoxia ◽  
Sensor Kinase ◽  
Site Mutation ◽  
Aerobic Conditions ◽  
Mutant Strains

The DevR–DevS/DosR–DosS two-component system of Mycobacterium tuberculosis, that comprises of DevS sensor kinase and DevR response regulator, is essential for bacterial adaptation to hypoxia by inducing dormancy regulon expression. The dominant phosphatase activity of DevS under aerobic conditions enables tight negative control, whereas its kinase function activates DevR under hypoxia to induce the dormancy regulon. A net balance in these opposing kinase and phosphatase activities of DevS calibrates the response output of DevR. To gain mechanistic insights into the kinase-phosphatase balance of DevS, we generated alanine substitution mutants of five residues located in DHp α1 helix of DevS, namely Phe-403, Gly-406, Leu-407, Gly-411 and His-415. For the first time, we have identified kinase positive phosphatase negative (K+P−) mutants in DevS by a single-site mutation in either Gly-406 or Leu-407. M. tuberculosis Gly-406A and Leu-407A mutant strains constitutively expressed the DevR regulon under aerobic conditions despite the presence of negative signal, oxygen. These mutant proteins exhibited ∼2-fold interaction defect with DevR. We conclude that Gly-406 and Leu-407 residues are individually essential for the phosphatase function of DevS. Our study provides new insights into the negative control mechanism of DevS by demonstrating the importance of an optimal interaction between DevR and DevS, and local changes associated with individual residues, Gly-406 and Leu-407, which mimic ligand-free DevS. These K+P− mutant strains are expected to facilitate the rapid aerobic screening of DevR antagonists in M. tuberculosis, thereby eliminating the requirement for hypoxic culture conditions.

scholarly journals The α10 helix of DevR, the Mycobacterium tuberculosis dormancy response regulator, regulates its DNA binding and activity

FEBS Journal ◽  
2016 ◽  
Vol 283 (7) ◽  
pp. 1286-1299 ◽  
Author(s):  
Atul Vashist ◽  
D. Prithvi Raj ◽  
Umesh Datta Gupta ◽  
Rajiv Bhat ◽  
Jaya Sivaswami Tyagi
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Dna Binding ◽  
Response Regulator

scholarly journals Evolutionary rewiring: a modified prokaryotic gene-regulatory pathway in chloroplasts

2013 ◽  
Vol 368 (1622) ◽  
pp. 20120260 ◽  
Author(s):  
Sujith Puthiyaveetil ◽  
Iskander M. Ibrahim ◽  
John F. Allen
Keyword(s):  
Green Algae ◽  
Gene Transcription ◽  
Response Regulator ◽  
Regulatory System ◽  
Photosynthetic Electron Transport ◽  
Sensor Kinase ◽  
Ps I ◽  
Component Systems ◽  
Two Component Systems ◽  
Gene Regulatory

Photosynthetic electron transport regulates chloroplast gene transcription through the action of a bacterial-type sensor kinase known as chloroplast sensor kinase (CSK). CSK represses photosystem I (PS I) gene transcription in PS I light and thus initiates photosystem stoichiometry adjustment. In cyanobacteria and in non-green algae, CSK homologues co-exist with their response regulator partners in canonical bacterial two-component systems. In green algae and plants, however, no response regulator partner of CSK is found. Yeast two-hybrid analysis has revealed interaction of CSK with sigma factor 1 (SIG1) of chloroplast RNA polymerase. Here we present further evidence for the interaction between CSK and SIG1. We also show that CSK interacts with quinone. Arabidopsis SIG1 becomes phosphorylated in PS I light, which then specifically represses transcription of PS I genes. In view of the identical signalling properties of CSK and SIG1 and of their interactions, we suggest that CSK is a SIG1 kinase. We propose that the selective repression of PS I genes arises from the operation of a gene-regulatory phosphoswitch in SIG1. The CSK-SIG1 system represents a novel, rewired chloroplast-signalling pathway created by evolutionary tinkering. This regulatory system supports a proposal for the selection pressure behind the evolutionary stasis of chloroplast genes.

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