Pilus phase variation switches gonococcal adherence to invasion by caveolin-1-dependent host cell signaling

PLoS Pathog. 2013;9(5):e1003373. doi: 10.1371/journal.ppat.1003373. Epub 2013 May 23.

Abstract

Many pathogenic bacteria cause local infections but occasionally invade into the blood stream, often with fatal outcome. Very little is known about the mechanism underlying the switch from local to invasive infection. In the case of Neisseria gonorrhoeae, phase variable type 4 pili (T4P) stabilize local infection by mediating microcolony formation and inducing anti-invasive signals. Outer membrane porin PorB(IA), in contrast, is associated with disseminated infection and facilitates the efficient invasion of gonococci into host cells. Here we demonstrate that loss of pili by natural pilus phase variation is a prerequisite for the transition from local to invasive infection. Unexpectedly, both T4P-mediated inhibition of invasion and PorB(IA)-triggered invasion utilize membrane rafts and signaling pathways that depend on caveolin-1-Y14 phosphorylation (Cav1-pY14). We identified p85 regulatory subunit of PI3 kinase (PI3K) and phospholipase Cγ1 as new, exclusive and essential interaction partners for Cav1-pY14 in the course of PorBIA-induced invasion. Active PI3K induces the uptake of gonococci via a new invasion pathway involving protein kinase D1. Our data describe a novel route of bacterial entry into epithelial cells and offer the first mechanistic insight into the switch from local to invasive gonococcal infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Adhesion*
  • Caveolin 1 / genetics
  • Caveolin 1 / metabolism*
  • Cell Line
  • Fimbriae, Bacterial / genetics
  • Fimbriae, Bacterial / metabolism*
  • Gonorrhea / genetics
  • Gonorrhea / metabolism*
  • Humans
  • Membrane Microdomains / genetics
  • Membrane Microdomains / metabolism
  • Membrane Microdomains / microbiology
  • Neisseria gonorrhoeae / genetics
  • Neisseria gonorrhoeae / metabolism*
  • Neisseria gonorrhoeae / pathogenicity
  • Phosphatidylinositol 3-Kinases / genetics
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phospholipase C gamma / genetics
  • Phospholipase C gamma / metabolism
  • Protein Kinase C / genetics
  • Protein Kinase C / metabolism
  • Signal Transduction*

Substances

  • CAV1 protein, human
  • Caveolin 1
  • protein kinase D
  • Protein Kinase C
  • Phospholipase C gamma

Grants and funding

This work was supported by ERA-NET PathoGenoMics 2 to TFM and to TR (BMBF/PTJ FKZ 0315435B) and SFB630 to TR. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.