Self-protective responses to norvaline-induced stress in a leucyl-tRNA synthetase editing-deficient yeast strain

Ji, Qiu; Fang, Zhipeng; Ye, Qing; Chi, Cheng-Wu; Wang, En‐Duo

doi:10.1093/nar/gkx487

Cited by 15 publications

(11 citation statements)

References 62 publications

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“…Leucine but not isoleucine or valine rescued growth (Fig 5B). These observations corroborate the results that LeuRSs contain natural selectivity with their aminoacylation site for leucine and can discriminate against isoleucine and valine, but to a lesser extent against norvaline as non-cognate amino acids [34].…”

Section: Norvaline Is Toxic To Editing-deficient Ept Mutantssupporting

confidence: 89%

Efficacy of epetraborole against Mycobacterium abscessus is increased with norvaline

et al. 2021

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Mycobacterium abscessus is the most common rapidly growing non-tuberculous mycobacteria to cause pulmonary disease in patients with impaired lung function such as cystic fibrosis. M. abscessus displays high intrinsic resistance to common antibiotics and inducible resistance to macrolides like clarithromycin. As such, M. abscessus is clinically resistant to the entire regimen of front-line M. tuberculosis drugs, and treatment with antibiotics that do inhibit M. abscessus in the lab results in cure rates of 50% or less. Here, we identified epetraborole (EPT) from the MMV pandemic response box as an inhibitor against the essential protein leucyl-tRNA synthetase (LeuRS) in M. abscessus. EPT protected zebrafish from lethal M. abscessus infection and did not induce self-resistance nor against clarithromycin. Contrary to most antimycobacterials, the whole-cell activity of EPT was greater against M. abscessus than M. tuberculosis, but crystallographic and equilibrium binding data showed that EPT binds LeuRSMabs and LeuRSMtb with similar residues and dissociation constants. Since EPT-resistant M. abscessus mutants lost LeuRS editing activity, these mutants became susceptible to misaminoacylation with leucine mimics like the non-proteinogenic amino acid norvaline. Proteomic analysis revealed that when M. abscessus LeuRS mutants were fed norvaline, leucine residues in proteins were replaced by norvaline, inducing the unfolded protein response with temporal changes in expression of GroEL chaperonins and Clp proteases. This supports our in vitro data that supplementation of media with norvaline reduced the emergence of EPT mutants in both M. abscessus and M. tuberculosis. Furthermore, the combination of EPT and norvaline had improved in vivo efficacy compared to EPT in a murine model of M. abscessus infection. Our results emphasize the effectiveness of EPT against the clinically relevant cystic fibrosis pathogen M. abscessus, and these findings also suggest norvaline adjunct therapy with EPT could be beneficial for M. abscessus and other mycobacterial infections like tuberculosis.

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Section: Norvaline Is Toxic To Editing-deficient Ept Mutantssupporting

confidence: 89%

Efficacy of epetraborole against Mycobacterium abscessus is increased with norvaline

et al. 2021

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“…These observations corroborate the results from Ji et al (2017) that LeuRSs contain natural selectivity with their aminoacylation site for leucine and can discriminate against isoleucine and valine, but to a lesser extent against norvaline as non-cognate amino acids. 31…”

Section: Resultsmentioning

confidence: 99%

Efficacy of epetraborole against Mycobacterium abscessus is increased with norvaline

Sullivan

Lupien

Kalthoff

et al. 2021

Preprint

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Certain aminoacyl-tRNA synthetases developed a proofreading mechanism to ensure aminoacylation of tRNAs with cognate amino acids. Epetraborole (EPT) was identified as an inhibitor of the leucyl-tRNA synthetase (LeuRS) editing site in Mycobacterium abscessus. EPT displayed enhanced activity against M. abscessus over Mycobacterium tuberculosis. Crystallographic and equilibrium binding data showed that EPT binds LeuRSMabs and LeuRSMtb with similar Kd. Proteomic analysis revealed that when M. abscessus LeuRS mutants were fed the non-proteinogenic amino acid norvaline, leucine residues in proteins were replaced by norvaline, inducing expression of GroEL chaperonins and Clp proteases. In vitro data revealed that supplementation of media with norvaline reduced the emergence of EPT mutants in both M. abscessus and M. tuberculosis. The combination of EPT and norvaline had improved in vivo efficacy compared to EPT in a murine model of M. abscessus infection.

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“…We also show that ablating AlaRS editing attenuates the heatshock response and causes heat sensitivity (Figures 1 , 4 and 7 ). In contrast, LeuRS editing deficiency as well as Ala misincorporation at Pro codons activate the heatshock response ( 20 , 62 ). It becomes increasingly clear that the editing function of different aaRSs may regulate distinct cellular response pathways.…”

Section: Discussionmentioning

confidence: 99%

“…Editing deficiency in phenylalanyl-tRNA synthetase (PheRS) also shows no growth effect in E. coli unless an oxidized form of tyrosine ( meta -tyrosine) accumulates ( 19 ). In yeast, leucyl-tRNA synthetase (LeuRS) editing defects does not affect growth under normal conditions ( 20 ). In contrast, mild editing defects in alanyl-tRNA synthetase (AlaRS) lead to neurodegeneration (loss of Purkinje cells) and cardiac proteinopathy in mice, and a more severe AlaRS editing defect is embryonic lethal ( 21 , 22 ).…”

Section: Introductionmentioning

confidence: 99%

Impact of alanyl-tRNA synthetase editing deficiency in yeast

Zhang

Lyu

et al. 2021

Nucleic Acids Research

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Aminoacyl-tRNA synthetases (aaRSs) are essential enzymes that provide the ribosome with aminoacyl-tRNA substrates for protein synthesis. Mutations in aaRSs lead to various neurological disorders in humans. Many aaRSs utilize editing to prevent error propagation during translation. Editing defects in alanyl-tRNA synthetase (AlaRS) cause neurodegeneration and cardioproteinopathy in mice and are associated with microcephaly in human patients. The cellular impact of AlaRS editing deficiency in eukaryotes remains unclear. Here we use yeast as a model organism to systematically investigate the physiological role of AlaRS editing. Our RNA sequencing and quantitative proteomics results reveal that AlaRS editing defects surprisingly activate the general amino acid control pathway and attenuate the heatshock response. We have confirmed these results with reporter and growth assays. In addition, AlaRS editing defects downregulate carbon metabolism and attenuate protein synthesis. Supplying yeast cells with extra carbon source partially rescues the heat sensitivity caused by AlaRS editing deficiency. These findings are in stark contrast with the cellular effects caused by editing deficiency in other aaRSs. Our study therefore highlights the idiosyncratic role of AlaRS editing compared with other aaRSs and provides a model for the physiological impact caused by the lack of AlaRS editing.

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Self-protective responses to norvaline-induced stress in a leucyl-tRNA synthetase editing-deficient yeast strain

Cited by 15 publications

References 62 publications

Efficacy of epetraborole against Mycobacterium abscessus is increased with norvaline

Efficacy of epetraborole against Mycobacterium abscessus is increased with norvaline

Efficacy of epetraborole against Mycobacterium abscessus is increased with norvaline

Impact of alanyl-tRNA synthetase editing deficiency in yeast

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