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PPE and PE_PGRS proteins of Mycobacterium marinum are transported via the type VII secretion system ESX-5

Abdallah M Abdallah1, Theo Verboom, Eveline M Weerdenburg

  • 1Department of Medical Microbiology and Infection Control, VU University Medical Centre, Amsterdam, the Netherlands.

Molecular Microbiology
|July 16, 2009
PubMed

Insights

The ESX-5 secretion system in mycobacteria is crucial for transporting PE_PGRS and PPE proteins. This study reveals ESX-5

Area of Science:

  • Microbiology
  • Molecular Biology
  • Proteomics

Background:

  • Mycobacteria possess five type VII secretion systems, including ESX-5.
  • PE and PPE protein families are unique to mycobacteria and linked to virulence.
  • ESX-5 is an ESAT-6-like secretion system.

Purpose of the Study:

  • To determine the secretome of the ESX-5 secretion system in Mycobacterium marinum.
  • To identify proteins transported by ESX-5, focusing on PE_PGRS and PPE families.

Main Methods:

  • Proteomic analysis of wild-type and ESX-5 mutant strains of Mycobacterium marinum.
  • Utilized a monoclonal antibody targeting the PGRS domain of PE_PGRS proteins.

Main Results:

  • ESX-5 is essential for the transport of numerous PE_PGRS and PPE-MPTR proteins.
  • Nearly all recognized PE_PGRS proteins were absent in the supernatant of ESX-5 mutants.
  • ESX-5 also secretes ESAT-6-like proteins.

Conclusions:

  • ESX-5 is a major secretion pathway in mycobacteria.
  • This system facilitates the secretion of recently evolved PE_PGRS and PPE proteins.
  • ESX-5 plays a significant role in the virulence of pathogenic mycobacteria.

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