PilC of pathogenic <i>Neisseria</i> is associated with the bacterial cell surface

Rahman, Motiur; Källström, Helena; Normark, Staffan; Jonsson, Ann‐Beth

doi:10.1046/j.1365-2958.1997.4601823.x

Cited by 108 publications

(120 citation statements)

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“…Similarly, two fusion proteins containing fragments of MS11 PilC1 were constructed and purified. PilC.A contains the N-terminal part of the PilC1 protein (aa 1-257), whereas PilC.C is composed of the C-terminal part of the PilC1 (aa 501-1016), both followed by the MBP fusion partner (32). Concentrations of fusion proteins were measured using the Bio-Rad protein assay (Hercules, CA).…”

Section: Proteinsmentioning

confidence: 99%

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A Novel Interaction Between Type IV Pili ofNeisseria gonorrhoeaeand the Human Complement Regulator C4b-Binding Protein

Blom

Rytkönen

Vásquez

et al. 2001

The Journal of Immunology

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C4b-binding protein (C4BP) is an important plasma inhibitor of the classical pathway of complement activation. Several bacterial pathogens bind C4BP, which may contribute to their virulence. In the present report we demonstrate that isolated type IV pili from Neisseria gonorrhoeae bind human C4BP in a dose-dependent and saturable manner. C4BP consists of seven identical α-chains and one β-chain linked together with disulfide bridges. We found that pili bind to the α-chain of C4BP, which is composed of eight homologous complement control protein (CCP) domains. From the results of an inhibition assay with C4b and a competition assay in which we tested mutants of C4BP lacking individual CCPs, we concluded that the binding area for pili is localized to CCP1 and CCP2 of the α-chain. The binding between pili and C4BP was abolished at 0.25 M NaCl, implying that it is based mostly on ionic interactions, similarly to what have been observed for C4b-C4BP binding. Furthermore, the N-terminal part of PilC, a structural component of pili, appeared to be responsible for binding of C4BP. Membrane cofactor protein, previously shown to be a receptor for pathogenic N. gonorrhoeae on the surface of epithelial cells, competed with C4BP for binding to pili only at high concentrations, suggesting that different parts of pili are involved in these two interactions. Accordingly, high concentrations of C4BP were required to inhibit binding of N. gonorrhoeae to Chang conjunctiva cells, and no inhibition of binding was observed with cervical epithelial cells.

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Section: Proteinsmentioning

confidence: 99%

“…Concentrations of fusion proteins were measured using the Bio-Rad protein assay (Hercules, CA). A polyclonal anti-PilC Ab was generated against a fusion protein containing the C-terminal half of MS11 PilC1 (32).…”

Section: Proteinsmentioning

confidence: 99%

A Novel Interaction Between Type IV Pili ofNeisseria gonorrhoeaeand the Human Complement Regulator C4b-Binding Protein

Blom

Rytkönen

Vásquez

et al. 2001

The Journal of Immunology

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“…Two other homologous proteins, PilC1 and PilC2, are also involved in pilus assembly and adhesion (Nassif et al, 1994;Rudel et al, 1995;Rahman et al, 1997).…”

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confidence: 99%

Down‐regulation of pili and capsule of Neisseria meningitidis upon contact with epithelial cells is mediated by CrgA regulatory protein

Deghmane¹,

Giorgini²,

Larribe³

et al. 2002

Molecular Microbiology

131

146

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SummaryThe initial attachment of Neisseria meningitidis to the target cell surface appears to be largely pilus dependent in capsulated bacteria. Intimate adhesion subsequently occurs to permit colonization. We recently reported that insertional inactivation of the crgA gene, which encodes a transcriptional regulator belonging to the LysR family, decreased meningococcal adhesion to epithelial cells and abolished intimate adhesion. In this report, we analyse expression of the pilE and sia genes, which are involved in the biosynthesis of pili and capsule respectively, during bacteria-host cell interactions. Western blotting, transcriptional fusion and reverse transcriptase polymerase chain reaction (RT-PCR) analysis showed that the expression of these genes was downregulated during intimate adhesion. DNA-binding assays, footprinting and RT-PCR analysis indicated that this downregulation was directly mediated by the CrgA protein. The pilE and sia promoters were found to have a CrgA binding motif in common. These results strongly suggest that N. meningitidis displays an adaptive response upon cell contact. CrgA may play a central regulatory role in meningococcal adhesion, particularly in switching from initial to intimate adhesion by downregulating the bacterial surface structures that hinder this adhesion.

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“…Gonococcal fimbriae can be fully reconstituted from cloned PilE protein in a heterologous species. Along with these subunits of fimbriae, several co-localized accessory genes have been identified and implicated in fimbrial assembly or function (Darzins and Russell, 1997). PilC is located at the tips of fimbriae as a minor subunit and is also found at the base of the fiber (Rahman et al, 1997 (Lory, 1998). This suggests that these pseudopilin subunits may form a structure similar to that ofType 4 pili.…”

Section: (B) Type 4 Fimbriaementioning

confidence: 94%

Molecular Strategies for Fimbrial Expression and Assembly

Fives-Taylor

2001

Critical Reviews in Oral Biology & Medicine

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Fimbriae or pili are long, filamentous, multimeric macromolecules found on the bacterial cell surface. Bacteria express a diverse array of fimbriae or pili that are involved in bacterial adherence and invasion. Fimbriae can be categorized based on their modes of expression and assembly. Type 1 fimbriae and P pili are distributed peritrichously and translocated to the cell surface by a chaperone/usher pathway. Type 4 pili are located at the pole of the cell and assembled via the type 11 secretion system. Curli fimbriae are coiled surface structures assembled by an extracellular nucleation/precipitation pathway. Fimbriae of oral Gram-negative and Gram-positive bacteria have not been well-studied as compared with the fimbriae of enteric pathogens. Oral pathogens, such as Eikenella corrodens, Actinobacillus actinomycetemcomitans, and Porphyromonas gingivalis, possess fimbriae that have been implicated in bacterial adhesion and invasion. These fimbriae are potential virulence factors in oral infectious processes. A. actinomycetemcomitans and E. corrodens have Type 4-like fimbriae, whereas P. gingivalis displays a unique type of fimbriae. To date, fimbriae of the oral primary colonizers, Actinomyces naeslundii and Streptococcus parasanguis, represent the only fimbriae characterized for any Gram-positive bacteria. The putative major fimbrial subunits, FimA and FimP of A. naeslundii and FapI of S. parasanguis, contain a signal sequence and cell-wall-sorting signal. The presence of extensive dipeptide repeats in FapI makes it unique among fimbrial molecules. Based on experimental data, a nucleation/precipitation pathway is proposed for fimbrial biogenesis of both S. parasanguis and A. naeslundii, although we cannot rule out an alternative covalent linkage model. The model systems described in this review served as a framework for hypotheses for how the known molecular factors of fimbriae on oral bacteria may be expressed and assembled.

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PilC of pathogenic Neisseria is associated with the bacterial cell surface

Cited by 108 publications

References 50 publications

A Novel Interaction Between Type IV Pili ofNeisseria gonorrhoeaeand the Human Complement Regulator C4b-Binding Protein

A Novel Interaction Between Type IV Pili ofNeisseria gonorrhoeaeand the Human Complement Regulator C4b-Binding Protein

Down‐regulation of pili and capsule of Neisseria meningitidis upon contact with epithelial cells is mediated by CrgA regulatory protein

Molecular Strategies for Fimbrial Expression and Assembly

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