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Pseudomonas aeruginosa minor pilins are incorporated into type IV pili

Carmen L Giltner1, Marc Habash, Lori L Burrows

  • 1Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada L8N 3Z5.

Journal of Molecular Biology
|March 27, 2010
PubMed

Insights

Minor pilins are essential components of Type IV pili, crucial for bacterial adhesion and twitching motility. This study reveals their role in initiating pilus assembly, not its termination.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Bacterial Cell Biology

Background:

  • Type IV pili are vital for bacterial adhesion and twitching motility.
  • Five conserved 'minor' pilins (FimU, PilV, PilW, PilX, PilE) are involved in pilus function but their specific roles remain unclear.
  • Maintaining a precise stoichiometric ratio of minor pilins is critical for pilus functionality.

Purpose of the Study:

  • To elucidate the specific functions of the five conserved minor pilins in Type IV pilus assembly and function.
  • To investigate the incorporation of minor pilins into the pilus structure.
  • To determine the role of minor pilins in the initiation and termination of pilus assembly.

Main Methods:

  • Genetic manipulation of minor pilin genes and the AlgR regulator in Pseudomonas aeruginosa.
  • Analysis of pilus production and piliation levels in mutant strains, including those with blocked pilus retraction (pilT inactivation).
  • Immunological detection using specific antibodies to confirm the processing and incorporation of minor pilins by the PilD peptidase.

Main Results:

  • Disruption of individual minor pilin genes or AlgR reduced piliation levels, indicating their importance in pilus biogenesis.
  • FimU and PilX were identified as key promoters of pilus assembly on the cell surface.
  • All five minor pilins were shown to be processed by PilD and incorporated into the pilus fiber.

Conclusions:

  • The minor pilins are integral components of Type IV pili, incorporated throughout the pilus filament.
  • These proteins play a crucial role in the initiation of pilus assembly.
  • This study provides the first evidence for the incorporation of these conserved minor pilins into the pilus fiber and their function in assembly initiation.

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