Type IV pili and twitching motility

Annu Rev Microbiol. 2002:56:289-314. doi: 10.1146/annurev.micro.56.012302.160938. Epub 2002 Jan 30.


Twitching motility is a flagella-independent form of bacterial translocation over moist surfaces. It occurs by the extension, tethering, and then retraction of polar type IV pili, which operate in a manner similar to a grappling hook. Twitching motility is equivalent to social gliding motility in Myxococcus xanthus and is important in host colonization by a wide range of plant and animal pathogens, as well as in the formation of biofilms and fruiting bodies. The biogenesis and function of type IV pili is controlled by a large number of genes, almost 40 of which have been identified in Pseudomonas aeruginosa. A number of genes required for pili assembly are homologous to genes involved in type II protein secretion and competence for DNA uptake, suggesting that these systems share a common architecture. Twitching motility is also controlled by a range of signal transduction systems, including two-component sensor-regulators and a complex chemosensory system.

Publication types

  • Review

MeSH terms

  • Bacteria / genetics
  • Bacterial Adhesion / physiology
  • Fimbriae, Bacterial / genetics
  • Fimbriae, Bacterial / physiology*
  • Fimbriae, Bacterial / ultrastructure*
  • Models, Biological
  • Movement / physiology*
  • Signal Transduction