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An orphaned Mce-associated membrane protein of Mycobacterium tuberculosis is a virulence factor that stabilizes Mce

Ellen Foot Perkowski1, Brittany K Miller1, Jessica R McCann1

  • 1Department of Microbiology and Immunology, University of North Carolina.

Molecular Microbiology
|December 30, 2015
PubMed

Insights

Mycobacterium tuberculosis protein OmamA (Rv0199) is crucial for virulence, enabling cholesterol import and stabilizing Mce transporters. This research clarifies the function of OmamA and related Mam proteins in Mce transport systems.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Tuberculosis Research

Background:

  • Exported proteins of Mycobacterium tuberculosis are potential virulence factors, but their functions are often unknown.
  • Rv0199 was previously identified as an exported membrane protein with an uncharacterized role.

Purpose of the Study:

  • To investigate the function of Rv0199 in Mycobacterium tuberculosis virulence.
  • To characterize the role of Rv0199 within the Mce-associated membrane (Mam) protein family.

Main Methods:

  • Utilized an aerosol model of murine infection to assess M. tuberculosis virulence.
  • Investigated the role of Rv0199 in Mce transporter function and protein complex stabilization.
  • Employed structural similarity predictions (Phyre 2) to compare Mam proteins with known systems.

Main Results:

  • Rv0199, renamed OmamA, is essential for cholesterol import, a process dependent on the Mce4 transporter.
  • OmamA plays a role in stabilizing components of the Mce1 transporter complex.
  • Structural similarities suggest OmamA's function may be analogous to VirB8 in Type IV secretion systems.

Conclusions:

  • OmamA is a multifunctional protein involved in multiple Mce transporters within Mycobacterium tuberculosis.
  • This study elucidates the function of OmamA and provides insights into the broader role of Mam family proteins in Mce transport.
  • Understanding OmamA's function contributes to knowledge of M. tuberculosis virulence mechanisms.

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