title: Neisseria gonorrhoeae PilV, a type IV pilus-associated protein essential to human epithelial cell adherence.
abstract: Type IV pili (Tfp) of Neisseria gonorrhoeae, the Gram-negative etiologic agent of gonorrhea, facilitate colonization of the human host. Tfp are assumed to play a key role in the initial adherence to human epithelial cells by virtue of the associated adhesin protein PilC. To examine the structural and functional basis for adherence in more detail, we identified potential genes encoding polypeptides sharing structural similarities to PilE (the Tfp subunit) within the N. gonorrhoeae genome sequence database. We show here that a fiber subunit-like protein, termed PilV, is essential to organelle-associated adherence but dispensable for Tfp biogenesis and other pilus-related phenotypes, including autoagglutination, competence for natural transformation, and twitching motility. The adherence defect in pilV mutants cannot be attributed to reduced levels of piliation, defects in fiber anchoring to the bacterial cell surface, or to unstable pilus expression related to organelle retraction. PilV is expressed at low levels relative to PilE and copurifies with Tfp fibers in a PilC-dependent fashion. Purified Tfp from pilV mutants contain PilC adhesin at reduced levels. Taken together, these data support a model in which PilV functions in adherence by promoting the functional display of PilC in the context of the pilus fiber.
authors.affiliation: Biotechnology Center of Oslo and Department of Microbiology, Institute of Pharmacy, University of Oslo, 0316 Oslo, Norway.
authors.forename: H C
authors.initials: HC
authors.lastname: Winther-Larsen
authors.forename: F T
authors.initials: FT
authors.lastname: Hegge
authors.forename: M
authors.initials: M
authors.lastname: Wolfgang
authors.forename: S F
authors.initials: SF
authors.lastname: Hayes
authors.forename: J P
authors.initials: JP
authors.lastname: van Putten
authors.forename: M
authors.initials: M
authors.lastname: Koomey
mesh_terms: D000595:Amino Acid Sequence; D001422:Bacterial Adhesion / Q000502:physiology*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D001483:Base Sequence; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D004847:Epithelial Cells / Q000382:microbiology; D036781:Fimbriae Proteins; D010861:Fimbriae, Bacterial; D006801:Humans; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009344:Neisseria gonorrhoeae / Q000502:physiology* / Q000648:ultrastructure; D016366:Open Reading Frames; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; C077573:PilV protein, Bacteria; C079208:pilC protein, Neisseria gonorrhoeae; D036781:Fimbriae Proteins