HigB1 Toxin in Mycobacterium tuberculosis Is Upregulated During Stress and Required to Establish Infection in Guinea Pigs

Sharma, Arun; Sagar, Kalpana; Chauhan, Neeraj; Venkataraman, Balaji; Gupta, Nidhi; Gosain, Tannu Priya; Bhalla, Nikhil; Singh, Ramandeep; Gupta, Amita

doi:10.3389/fmicb.2021.748890

Cited by 10 publications

(8 citation statements)

References 102 publications

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“…These observations imply that MenT2 is essential for successful colonization or bacterial dissemination from the lungs to the spleens. Other mutant strains of M. tuberculosis, such as Δhbha, ΔrelA, ΔdevR, ΔhigB1 and ΔmymA, have shown similarly attenuated phenotypes [76,[78][79][80]. The tissue damage was similar in the spleens and lungs of guinea pigs infected with the parental and complemented strains.…”

Section: Discussionmentioning

confidence: 89%

“…We have also previously reported that M. tuberculosis with individual deletion of either toxins or TA complexes are impaired for growth in animals [20, 23, 24, 27, 76]. However, the growth of the parental, Δ vapC28 , Δ vapC21 and ΔdarTG mutant strains was similar in animal tissues [20, 25, 77].…”

Section: Discussionmentioning

confidence: 91%

“…Other mutant strains of M. tuberculosis , such as Δ hbha , Δ relA , Δ devR , Δ higB1 and Δ mymA , have shown similarly attenuated phenotypes [76, 78–80]. The tissue damage was similar in the spleens and lungs of guinea pigs infected with the parental and complemented strains.…”

Section: Discussionmentioning

confidence: 99%

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Disruption of MenT2 toxin impairs the growth of Mycobacterium tuberculosis in guinea pigs

Gosain

Singh

et al. 2022

Microbiology

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Toxin–antitoxin (TA) systems are abundantly present in the genomes of various bacterial pathogens. TA systems have been implicated in either plasmid maintenance or protection against phage infection, stress adaptation or disease pathogenesis. The genome of Mycobacterium tuberculosis encodes for more than 90 TA systems and 4 of these belong to the type IV subfamily (MenAT family). The toxins and antitoxins belonging to type IV TA systems share sequence homology with the AbiEii family of nucleotidyl transferases and the AbiEi family of putative transcriptional regulators, respectively. Here, we have performed experiments to understand the role of MenT2, a toxin from the type IV TA system, in mycobacterial physiology and disease pathogenesis. The ectopic expression of MenT2 using inducible vectors does not inhibit bacterial growth in liquid cultures. Bioinformatic and molecular modelling analysis suggested that the M. tuberculosis genome has an alternative start site upstream of the annotated menT2 gene. The overexpression of the reannotated MenT2 resulted in moderate growth inhibition of Mycobacterium smegmatis . We show that both menT2 and menA2 transcript levels are increased when M. tuberculosis is exposed to nitrosative stress, in vitro. When compared to the survival of the wild-type and the complemented strain, the ΔmenT2 mutant strain of M. tuberculosis was more resistant to being killed by nitrosative stress. However, the survival of both the ΔmenT2 mutant and the wild-type strain was similar in macrophages and when exposed to other stress conditions. Here, we show that MenT2 is required for the establishment of disease in guinea pigs. Gross pathology and histopathology analysis of lung tissues from guinea pigs infected with the ∆menT2 strain revealed significantly reduced tissue damage and inflammation. In summary, these results provide new insights into the role of MenT2 in mycobacterial pathogenesis.

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Section: Discussionmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 91%

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Disruption of MenT2 toxin impairs the growth of Mycobacterium tuberculosis in guinea pigs

Gosain

Singh

et al. 2022

Microbiology

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“…Typically, Type II modules are composed of a protein toxin and a cognate antitoxin protein that interact via protein-protein interaction (17). While several Type II systems have been evaluated in E. coli and M. smegmatis for their cytotoxicity (18)(19)(20)(21) others such as VapBC, MazEF, ParDE, RelBE and HigAB have been implicated in stress-induced survival of M. tuberculosis (19,(22)(23)(24)(25).…”

Section: Introductionmentioning

confidence: 99%

Ser/Thr Phosphorylation ofMycobacterium tuberculosisType II Rel TA module by Protein Kinase K interferes with toxin neutralization: A novel mode of TA regulation

Sarah,

Garg,

Korch

et al. 2023

Preprint

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Toxin-Antitoxin (TA) modules represent genetic elements implicated in bacterial persistence and antibiotic tolerance. Remarkably,Mycobacterium tuberculosisencodes 90+ TA modules, the majority of which are Type II TA comprising of a toxin component and an antitoxin counterpart that neutralizes the toxin. Upon exposure to stress, the antitoxin is degraded, releasing the toxin which then acts to halt cellular growth. Given that TA modules dictate social behavior of a population, we hypothesize that their regulation must be exquisitely controlled to avoid superfluous growth inhibition and initiation of persistence. However, the regulation and coordination of TA modules is poorly understood. Herein, we describe for the first time, a novel regulatory mechanism for Type II TA modules involving post-translational modification (PTM). Using computational tools, we observed that over 85 % of theM. tuberculosisTA proteins possess potential Ser/Thr phosphosites highlighting them as putative substrates forM. tuberculosisSer/Thr protein kinases (STPK). We demonstrate that members of the RelBE family are subjected toO-phosphorylation by PknK, a stress-responsive growth regulatory STPK. Mass spectrometry confirmed multiple sites of PknK-mediated phosphorylation in the RelJK TA module. To gain insights into the functional impact of this PTM, we conductedin vitrobinding and phenotypic growth studies with the wild type and mutant RelJK proteins. Our findings indicate that phosphorylation of Thr77 residue in RelK toxin compromises its binding to the RelJ antitoxin. These results suggest a potential role forO-phosphorylation in influencing the interaction dynamics of the TA module components.ImportanceBacterial pathogens rely on the phenomenon of persistence as a survival strategy to combat the adverse environmental conditions encountered during infection. As a stochastic process, the driving force(s) that potentiate the formation of persisters in a bacterial population are largely unclear. This study is a step towards the discovery of intricate regulatory mechanisms that coordinate a synchronized TA cellular program. We propose a model wherein the TA module is regulated post translationally, specifically via Ser/Thr phosphorylation disrupting the interaction between the toxin and antitoxin proteins as a mechanism to regulate TA function.

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“…The TAC chaperone, which is homologous to the export chaperone SecB of E. coli 32,33 , specifically interacts with the C-terminal chaperoneaddiction region of the antitoxin to prevent its aggregation and degradation, and to facilitate subsequent inhibition of the toxin by the antitoxin [34][35][36] . Although transcription of TAC is induced under relevant stresses for M. tuberculosis, including nutritional starvation, hypoxia, antibiotics treatment, and drug-induced persistence 22,23,[37][38][39] , very little is known about its possible involvement in M. tuberculosis physiology and virulence 40 . Deletion of the HigA TAC antitoxin is lethal, possibly due to the synthesis of free active toxin 39 .…”

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confidence: 99%

Substrate recognition and cryo-EM structure of the ribosome-bound TAC toxin of Mycobacterium tuberculosis

Mansour

Giudice

et al. 2022

Nat Commun

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Toxins of toxin-antitoxin systems use diverse mechanisms to control bacterial growth. Here, we focus on the deleterious toxin of the atypical tripartite toxin-antitoxin-chaperone (TAC) system of Mycobacterium tuberculosis, whose inhibition requires the concerted action of the antitoxin and its dedicated SecB-like chaperone. We show that the TAC toxin is a bona fide ribonuclease and identify exact cleavage sites in mRNA targets on a transcriptome-wide scale in vivo. mRNA cleavage by the toxin occurs after the second nucleotide of the ribosomal A-site codon during translation, with a strong preference for CCA codons in vivo. Finally, we report the cryo-EM structure of the ribosome-bound TAC toxin in the presence of native M. tuberculosis cspA mRNA, revealing the specific mechanism by which the TAC toxin interacts with the ribosome and the tRNA in the P-site to cleave its mRNA target.

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HigB1 Toxin in Mycobacterium tuberculosis Is Upregulated During Stress and Required to Establish Infection in Guinea Pigs

Cited by 10 publications

References 102 publications

Disruption of MenT2 toxin impairs the growth of Mycobacterium tuberculosis in guinea pigs

Disruption of MenT2 toxin impairs the growth of Mycobacterium tuberculosis in guinea pigs

Ser/Thr Phosphorylation ofMycobacterium tuberculosisType II Rel TA module by Protein Kinase K interferes with toxin neutralization: A novel mode of TA regulation

Substrate recognition and cryo-EM structure of the ribosome-bound TAC toxin of Mycobacterium tuberculosis

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