Roles of PilC and PilE Proteins in Pilus-Mediated Adherence of Neisseria gonorrhoeae and Neisseria meningitidis to Human Erythrocytes and Endothelial and Epithelial Cells

Abstract

Unlike other type 4 pili, the neisserial pili consist of at least two distinct proteins, the highly variable major subunit PilE forming the pilus fiber and the tip-associated adhesin PilC. PilC protein purified either from gonococci or from Escherichia coliinteracted with different human epithelial cell lines, primary epithelial and endothelial cells. The binding of PilC protein efficiently prevented the attachment of piliated Neisseria gonorrhoeae and Neisseria meningitidis to these cell types. Fluorescent beads coated with pili prepared from piliated wild-type N. gonorrhoeae also adhered to these cells, in contrast to beads coated with pili prepared from a piliated PilC-deficient mutant. In the latter case, the binding of fluorescent beads was restored after pretreatment of the pilus-loaded beads with purified PilC. Piliated wild-type N. gonorrhoeae, the piliated PilC-deficient mutant, and N. gonorrhoeae pili assembled in Pseudomonas aeruginosa agglutinated human erythrocytes, while nonpiliated gonococci did not. Consistently, purified PilC did not agglutinate or bind to human erythrocytes, suggesting that N. gonorrhoeae PilE is responsible for pilus-mediated hemagglutination.

Surface organelles assembled by secretion systems of Gram-negative bacteria: diversity in structure and function

“…For example, the PilC1 and PilC2 proteins of Neisseria spp. function as tip-located adhesins and also localize to the outer membrane to regulate pilus retraction (Nassif et al, 1994;Rudel et al, 1995a;Scheuerpflug et al, 1999;Morand et al, 2004).…”

“…use their T4P for colonization of human mucosal surfaces. PilC localizes to the pilus tip, and purified PilC has been shown to bind various human epithelial and endothelial cells (Scheuerpflug et al, 1999). The role of PilC is still controversial, however, as a direct requirement for PilC in host cell binding by Neisseria spp.…”

A conserved set of pilin‐like molecules controls type IV pilus dynamics and organelle‐associated functions in Neisseria gonorrhoeae

“…PilC influences Tfp dynamics and appears to promote adherence by virtue of its physical association with Tfp (Wolfgang et al, 1998b;Scheuerpflug et al, 1999). Given the similar alterations in Tfp dynamics and adherence defects in mutants lacking products of the pilH-L locus, we examined the influence of each gene product as well as PilC on the capacity of each protein to fractionate with Tfp in the pilT suppressor backgrounds (Fig.…”

“…The ability of PilT to impact on Tfp biogenesis was first observed in Ng pilC mutants (Wolfgang et al ., 1998b). Both biochemical and genetic data strongly implicate PilC as the Tfp associated adhesin for human epithelial cells (Wolfgang et al ., 1998b;Scheuerpflug et al ., 1999). In addition, PilC influences organelle expression as null mutants have extremely low Tfp levels (Jonsson et al ., 1991;Rudel et al ., 1995a).…”

T-cell stimulating protein A (TspA) of Neisseria meningitidis is required for optimal adhesion to human cells

“…Overall, our results suggest that the effect of the tspA mutation on adhesion is unlikely to be directly linked to the function of Tfp because all known Tfp-related phenotypes except adhesion appeared to be unaffected. Although levels of adherence of the tspA mutant were reduced several fold, by contrast meningoccci with impaired Tfp have levels of adherence typically~100-fold lower than the wild type (Scheuerpflug et al, 1999;Hélaine et al, 2005), depending on the cell type and methodology used. Furthermore, meningococcal and gonococcal Tfp are highly similar in their biosynthesis, architecture and function, and yet the genome of the gonococcal strain FA1090 does not contain a functional tspA gene.…”