Pili (Fimbriae) of Neisseria gonorrhoeae

This chapter discusses only the aspects of type IV piliation that are specific for N. gonorrhoeae. In particular, it reviews pilus-associated phenotypes, the regulation of pilin synthesis, pilus assembly, and pilus phase and antigenic variation. The major function of all bacterial pili is to express adhesive proteins away from the cell surface in order to mediate adherence to specific receptors. While piliation has been correlated with transformation competence, no direct role for pili in transformation has been discovered, and the molecular basis for the correlation remains unclear. There are some problems with the idea that PilA and PilB form a two-component system that regulates gonococcal pilin synthesis. The derived amino acid sequences of these proteins display little homology with those of known regulators and sensors. Using another approach, putative gonococcal pilus assembly genes have been identified by virtue of their DNA homology with the previously identified type IV pilus assembly genes of P.