Mycobacterium marinum down-regulates miR-148a in macrophages in an EsxA-dependent manner

Wu, Haichong; Bao, Yanqing; Wang, Lin; Li, Xiujun; Sun, Jianjun

doi:10.1016/j.intimp.2019.04.056

Cited by 14 publications

(16 citation statements)

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“…Protein expression was induced by adding 0.2% (w/v) acetamide for 12-16 h. The cells were harvested. The soluble heterodimer proteins were purified with immobilized metal ion affinity chromatography by passing through a Ni 2+column, followed by a sizing exclusion chromatography as previously described (27,(42)(43)(44)(45). Typical yield averaged between 20-40 mg/L of culture.…”

Section: Generation Of T2x Mutations On the Mtb Esxa Gene For Expressmentioning

confidence: 99%

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Nα-Acetylation of the virulence factor EsxA is required for mycobacterial cytosolic translocation and virulence

Aguilera

Karki

et al. 2020

Journal of Biological Chemistry

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The Mycobacterium tuberculosis virulence factor EsxA and its chaperone EsxB are secreted as a heterodimer (EsxA:B) and are crucial for mycobacterial escape from phagosomes and cytosolic translocation. Current findings support the idea that for EsxA to interact with host membranes, EsxA must dissociate from EsxB at low pH. However, the molecular mechanism by which the EsxA:B heterodimer separates is not clear. In the present study, using liposome-leakage and cytotoxicity assays, LC-MS/MS–based proteomics, and CCF-4 FRET analysis, we obtained evidence that the Nα-acetylation of the Thr-2 residue on EsxA, a post-translational modification that is present in mycobacteria but absent in Escherichia coli, is required for the EsxA:B separation. Substitutions at Thr-2 that precluded Nα-acetylation inhibited the heterodimer separation and hence prevented EsxA from interacting with the host membrane, resulting in attenuated mycobacterial cytosolic translocation and virulence. Molecular dynamics simulations revealed that at low pH, the Nα-acetylated Thr-2 makes direct and frequent “bind-and-release” contacts with EsxB, which generates a force that pulls EsxB away from EsxA. In summary, our findings provide evidence that the Nα-acetylation at Thr-2 of EsxA facilitates dissociation of the EsxA:B heterodimer required for EsxA membrane permeabilization and mycobacterial cytosolic translocation and virulence.

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Section: Generation Of T2x Mutations On the Mtb Esxa Gene For Expressmentioning

confidence: 99%

“…The mutations were confirmed by DNA sequencing. The mutated plasmids were electroporated into MmDEsxA:B as previously described (44).…”

Section: Generation Of T2x Mutations On the Mtb Esxa Gene For Expressmentioning

confidence: 99%

Nα-Acetylation of the virulence factor EsxA is required for mycobacterial cytosolic translocation and virulence

Aguilera

Karki

et al. 2020

Journal of Biological Chemistry

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Section: Generation Of T2x Mutations On the Esxa Gene For Expression mentioning

confidence: 99%

“…The mutations were confirmed by DNA sequencing. The mutated plasmids were electroporated into MmDEsxA:B as previously described (32).…”

Section: Generation Of T2x Mutations On the Esxa Gene For Expression mentioning

confidence: 99%

N^α-acetylation of EsxA is required for mycobacterial cytosolic translocation and virulence

Aguilera

et al. 2020

Preprint

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Mycobacterium tuberculosis virulence factors, EsxA and EsxB, are secreted as a heterodimer (EsxA:B) and play an essential role in mycobacterial phagosomal escape and cytosolic translocation. Current studies support a model that EsxA must dissociate from its chaperon EsxB at low pH in order for EsxA to interact with host membranes. However, the mechanism of the heterodimer separation is not clear. In the present study, we have obtained evidence that the N αacetylation of Thr2 on EsxA, a post-translational modification that is present in mycobacteria, but absent in E. coli, is required for the heterodimer separation. The point mutations at Thr2 without N α -acetylation inhibited the heterodimer separation and hence prevented EsxA from interacting with the membranes, which resulted in attenuated mycobacterial cytosolic translocation and virulence. Molecular dynamic simulation showed that at low pH the N αacetylated Thr2 made direct and frequent "bindand-release" contacts with EsxB, which generates a dragging force to pull EsxB away from EsxA. Conflicts of Interest:The authors declare there is no conflicts of interest in the content of this article.

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“…ESAT-6 (6-kDa early secreted antigenic target), a well-documented Mtb virulence factor, is essential for Mtb pathogenesis, including phagosomal rupture, mycobacterial cytosolic translocation and cell-to-cell spreading (Hsu et al, 2003; Stanley et al, 2003; Abdallah et al, 2007; van der Wel et al, 2007; Houben et al, 2012; Manzanillo et al, 2012; Simeone et al, 2012, 2015; Zhang et al, 2016). ESAT-6 appears to function as an important modulator of host inflammatory responses by manipulating several intracellular signaling pathways in macrophages, T cells, and epithelial cells (Tsao et al, 1999; Giacomini et al, 2001; Junqueira-Kipnis et al, 2006; Pathak et al, 2007; Koo et al, 2008; Kurenuma et al, 2009; Mishra et al, 2010; Samten et al, 2011; Wong and Jacobs, 2011; Wu et al, 2019). Here, Refai et al report a new role of ESAT-6 in macrophage differentiation and polarization.…”

Section: Introductionmentioning

confidence: 99%

Editorial: Cellular and Molecular Mechanisms of Mycobacterium tuberculosis Virulence

Sun

Champion

Bigi

2019

Front. Cell. Infect. Microbiol.

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Mycobacterium marinum down-regulates miR-148a in macrophages in an EsxA-dependent manner

Cited by 14 publications

References 62 publications

Nα-Acetylation of the virulence factor EsxA is required for mycobacterial cytosolic translocation and virulence

Nα-Acetylation of the virulence factor EsxA is required for mycobacterial cytosolic translocation and virulence

N^α-acetylation of EsxA is required for mycobacterial cytosolic translocation and virulence

Editorial: Cellular and Molecular Mechanisms of Mycobacterium tuberculosis Virulence

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Mycobacterium marinum down-regulates miR-148a in macrophages in an EsxA-dependent manner

Cited by 14 publications

References 62 publications

Nα-Acetylation of the virulence factor EsxA is required for mycobacterial cytosolic translocation and virulence

Nα-Acetylation of the virulence factor EsxA is required for mycobacterial cytosolic translocation and virulence

Nα-acetylation of EsxA is required for mycobacterial cytosolic translocation and virulence

Editorial: Cellular and Molecular Mechanisms of Mycobacterium tuberculosis Virulence

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Product

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N^α-acetylation of EsxA is required for mycobacterial cytosolic translocation and virulence