Cited by 215Tuberculosis Research and EpidemiologyBacterial Genetics and BiotechnologyMycobacterium research and diagnosis

Separable roles for Mycobacterium tuberculosis ESX-3 effectors in iron acquisition and virulence

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Tufariello, JoAnn M., Chapman, Jessica R., Kerantzas, Christopher A., Wong, Ka-Wing, Vilchèze, Catherine, Jones, Christopher M., Cole, Laura E., Tinaztepe, Emir +6 more·2016·Proceedings of the National Academy of Sciences

Abstract

Mycobacterium tuberculosis (Mtb) encodes five type VII secretion systems (T7SS), designated ESX-1-ESX-5, that are critical for growth and pathogenesis. The best characterized is ESX-1, which profoundly impacts host cell interactions. In contrast, the ESX-3 T7SS is implicated in metal homeostasis, but efforts to define its function have been limited by an inability to recover deletion mutants. We overcame this impediment using medium supplemented with various iron complexes to recover mutants with deletions encompassing select genes within esx-3 or the entire operon. The esx-3 mutants were defective in uptake of siderophore-bound iron and dramatically accumulated cell-associated mycobactin siderophores. Proteomic analyses of culture filtrate revealed that secretion of EsxG and EsxH was codependent and that EsxG-EsxH also facilitated secretion of several members of the proline-glutamic acid (PE) and proline-proline-glutamic acid (PPE) protein families (named for conserved PE and PPE N-terminal motifs). Substrates that depended on EsxG-EsxH for secretion included PE5, encoded within the esx-3 locus, and the evolutionarily related PE15-PPE20 encoded outside the esx-3 locus. In vivo characterization of the mutants unexpectedly showed that the ESX-3 secretion system plays both iron-dependent and -independent roles in Mtb pathogenesis. PE5-PPE4 was found to be critical for the siderophore-mediated iron-acquisition functions of ESX-3. The importance of this iron-acquisition function was dependent upon host genotype, suggesting a role for ESX-3 secretion in counteracting host defense mechanisms that restrict iron availability. Further, we demonstrate that the ESX-3 T7SS secretes certain effectors that are important for iron uptake while additional secreted effectors modulate virulence in an iron-independent fashion.

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Authors
Tufariello, J. M., Chapman, J. R., Kerantzas, C. A., Wong, K.-W., Vilchèze, C., Jones, C. M., Cole, L. E., Tinaztepe, E., Thompson, V., Fenyö, D., Niederweis, M., Ueberheide, B., Philips, J. A., & Jacobs, W. R.
Affiliations
  • Albert Einstein College of Medicine (US)
  • New York University (US)
  • Shanghai Medical College of Fudan University (CN)
  • University of Alabama at Birmingham (US)
  • NYU Langone Health (US)
Venue
Proceedings of the National Academy of Sciences
Published
2016-01-04
Volume
113
Issue
3
Pages
E348-57
ISSN
  • 0027-8424 (ISSN-L)
  • 1091-6490
OpenAlex
W2225338927
Cited by
215
References
78
Citations by year
2026: 20 · 2025: 26 · 2024: 15 · 2023: 20 · 2022: 23 · 2021: 20 · 2020: 18 · 2019: 25 · 2018: 19 · 2017: 17 · 2016: 12
FWCI
22.45
Type
journal article
Language
en
Open access
Locations
  • Proceedings of the National Academy of Sciences (publishedVersion)
  • Europe PMC (PubMed Central) (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • HHS | NIH | National Institute of Allergy and Infectious Diseases (AI26170, AI098925, AI087682)
  • Doris Duke Charitable Foundation (0000000)
  • New York University School of Medicine (0000000)
Topics
  • Health Sciences › Medicine › Infectious Diseases › Tuberculosis Research and Epidemiology
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Bacterial Genetics and Biotechnology
  • Health Sciences › Medicine › Epidemiology › Mycobacterium research and diagnosis
Keywords
Mycobacterium tuberculosis, type VII secretion system, iron acquisition, siderophores, mycobactin, virulence, host-pathogen interaction, metal homeostasis, culture filtrate proteins
MeSH terms
Aerosols, Animals, Bacterial Proteins, Genotype, Hemin, Humans, Iron, Macrophages, Mice, Inbred C57BL, Mutation, Mycobacterium tuberculosis, Oxazoles, Phenotype, Mass Spectrometry, Substrate Specificity, Virulence, Mice, SCID, Cell Polarity, Siderophores, Mice, Knockout, Homeodomain Proteins, Proteomics, Host-Pathogen Interactions

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