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Mycoplasma pneumoniae J-domain protein required for terminal organelle function

Jason M Cloward1, Duncan C Krause

  • 1Department of Microbiology, University of Georgia, Athens, GA 30602, USA.

Molecular Microbiology
|February 3, 2009
PubMed

Insights

Mycoplasma pneumoniae uses a J-domain protein, TopJ, to assemble its terminal organelle, essential for motility and adherence. Loss of TopJ disrupts organelle formation, impacting colonization.

Area of Science:

  • Microbiology
  • Cell Biology
  • Protein Biochemistry

Background:

  • Mycoplasma pneumoniae, a wall-less bacterium, causes respiratory infections.
  • Successful colonization relies on a polar terminal organelle for adherence and motility.
  • J-domain proteins are crucial for protein folding and assembly, often interacting with Hsp70 chaperones.

Purpose of the Study:

  • To investigate the function of the J-domain protein TopJ in Mycoplasma pneumoniae.
  • To determine TopJ's role in the assembly and function of the terminal organelle.
  • To elucidate the mechanism by which TopJ contributes to bacterial pathogenesis.

Main Methods:

  • Genetic manipulation to create a topJ deletion mutant.
  • Western immunoblotting to assess protein levels.
  • Fluorescence microscopy to evaluate protein localization and organelle assembly.
  • Complementation assays to restore gene function.

Main Results:

  • topJ mutant exhibited a non-motile and adherence-deficient phenotype.
  • Terminal organelle proteins failed to localize correctly in the mutant.
  • Complementation restored terminal organelle development, motility, and adherence.
  • TopJ localizes to the base of the terminal organelle in wild-type cells.

Conclusions:

  • TopJ is essential for the proper assembly and positioning of the Mycoplasma pneumoniae terminal organelle.
  • This J-domain protein plays a critical role in late-stage organelle development.
  • TopJ is vital for bacterial colonization of the respiratory epithelium through its role in terminal organelle function.

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