Fimbrial biogenesis genes of Pseudomonas aeruginosa: pilW and pilX increase the similarity of type 4 fimbriae to the GSP protein-secretion systems and pilY1 encodes a gonococcal PilC homologue

Mol Microbiol. 1996 Oct;22(1):161-73. doi: 10.1111/j.1365-2958.1996.tb02665.x.


Type 4 fimbriae of Pseudomonas aeruginosa are surface filaments involved in host colonization. They mediate both attachment to host epithelial cells and flagelia-independent twitching motility. Four additional genes, pilW, pilX, pilY1 and pilY2, are located on Spel fragment E in the 5 kb intergenic region between the previously characterized genes pilV and pilE, which encode prepilin-like proteins involved in type 4 fimbrial biogenesis. The phenotypes of a transposon insertion and other mutations constructed by allelic exchange show that these genes are involved in the assembly of type 4 fimbriae. The PilW and PilX proteins are membrane located, possess the hydrophobic N-terminus characteristic of prepilin-like proteins, and appear to belong to the GspJ and GspK group of proteins that are required for protein secretion in a wide range of Gram-negative bacteria. These findings increase the similarities between the fimbrial biogenesis and the Gsp-based protein-secretion supersystems. PilY1 is a large protein with C-terminal homology to the PilC2 protein of Neisseria gonorrhoeae, thought to be a fimbrial tip-associated adhesin, and which, like PilY1, is involved in fimbrial assembly. PilY1 appears to be located in both the membrane and the external fimbrial fractions. PilY2 is a small protein that appears to play a subtle role in fimbrial biogenesis and represents a new class of protein.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Amino Acid Sequence
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • DNA, Bacterial / genetics
  • Fimbriae Proteins*
  • Fimbriae, Bacterial / genetics*
  • Gene Expression
  • Genes, Bacterial*
  • Genetic Complementation Test
  • Membrane Proteins / genetics*
  • Molecular Sequence Data
  • Mutagenesis, Insertional
  • Mutation
  • Neisseria gonorrhoeae / genetics
  • Open Reading Frames
  • Phenotype
  • Pseudomonas aeruginosa / genetics*
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid


  • Bacterial Proteins
  • DNA, Bacterial
  • Membrane Proteins
  • PilX protein, Pseudomonas aeruginosa
  • PilY1 protein, Pseudomonas aeruginosa
  • pilC protein, Neisseria gonorrhoeae
  • Fimbriae Proteins

Associated data

  • GENBANK/M29691
  • GENBANK/M32613
  • GENBANK/U27184
  • GENBANK/X66504
  • GENBANK/X70049
  • GENBANK/Z49120