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Analysis of SecA2-dependent substrates in Mycobacterium marinum identifies protein kinase G (PknG) as a virulence

Aniek D van der Woude1, Esther J M Stoop, Michael Stiess

  • 1Department of Medical Microbiology and Infection Control, VU University Medical Center, van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands; Department of Molecular Microbiology, Institute of Molecular Cell Biology, VU University, de Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands.

Cellular Microbiology
|October 15, 2013
PubMed

Insights

Mycobacterium marinum

Area of Science:

  • Microbiology
  • Molecular Biology
  • Pathogenesis

Background:

  • Mycobacterial pathogenicity relies on exporting virulence factors.
  • The SecA2 secretion pathway is crucial for virulence but its effectors are unknown.
  • SecA2 pathway mutants exhibit impaired granuloma formation in zebrafish.

Purpose of the Study:

  • To identify SecA2-dependent effector proteins in Mycobacterium marinum.
  • To elucidate the role of SecA2 in the localization and function of virulence factors.
  • To understand the contribution of SecA2-dependent protein secretion to mycobacterial virulence.

Main Methods:

  • Comparative proteomics of wild-type and secA2 mutant M. marinum.
  • Immunoblotting to confirm protein localization.
  • Phenotypic analysis of secA2 mutants and PknG overexpression in zebrafish models.

Main Results:

  • Identified putative SecA2-dependent substrates, including protein kinase G (PknG).
  • Confirmed SecA2-dependent membrane localization of PknG.
  • Demonstrated that PknG overexpression partially restores virulence and phagosomal maturation inhibition in secA2 mutants.

Conclusions:

  • SecA2-dependent membrane localization of PknG is critical for Mycobacterium marinum virulence.
  • The SecA2 pathway contributes to virulence by secreting effectors like PknG.
  • PknG plays a significant role in the pathogenesis of M. marinum infections.

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