Tetratricopeptide Repeat Protein-Associated Proteins Contribute to the Virulence ofPorphyromonas gingivalis

Abstract

Porphyromonas gingivalis is one of the most etiologically important microorganisms in periodontal disease. We found in a previous study that PG1385 (TprA) protein, a tetratricopeptide repeat (TPR) protein, was upregulated in P. gingivalis wild-type cells placed in a mouse subcutaneous chamber and that a tprA mutant was clearly less virulent in the mouse subcutaneous abscess model (M. Yoshimura et al., Oral Microbiol. Immunol. 23:413-418, 2008). In the present study, we investigated the gene expression profile of tprA mutant cells placed in a mouse subcutaneous chamber and found that 9 genes, including PG2102 (tapA), PG2101 (tapB), and PG2100 (tapC) genes, were downregulated in the tprA mutant compared with those in the wild type. Expression of a cluster of tapA, tapB, and tapC genes of the mutant was also downregulated in an in vitro culture with enriched brain heart infusion medium. The TprA protein has three TPR motifs known as a protein-protein interaction module. Yeast two-hybrid system analysis and in vitro protein binding assays with immunoprecipitation and surface plasmon resonance detection revealed that the TprA protein could bind to TapA and TapB proteins. TprA and TapB proteins were located in the periplasmic space, whereas TapA, which appeared to be one of the C-terminal domain family proteins, was located at the outer membrane. We constructed tapA, tapB, and tapC single mutants and a tapA-tapB-tapC deletion mutant. In the mouse subcutaneous infection experiment, all of the mutants were less virulent than the wild type. These results suggest that TprA, TapA, TapB, and TapC are cooperatively involved in P. gingivalis virulence.Periodontal disease, the major cause of tooth loss in the general population of industrial nations (21, 37), is a chronic inflammatory disease of the periodontium that leads to erosion of the attachment apparatus and supporting bone for the teeth (1) and is one of the most common infectious diseases of humans (36). The obligately anaerobic Gram-negative bacterium Porphyromonas gingivalis has become recognized as a major pathogen for chronic periodontitis (7). P. gingivalis has been found to express numerous potential virulence factors, such as fimbriae, hemagglutinins, lipopolysaccharides, and various proteases that are capable of hydrolyzing collagen, immunoglobulins, iron-binding proteins, and complement factors (16,17). Expression of these virulence factors is thought to be tightly regulated in response to environmental cues. In recent years, the search for virulence factors has been greatly facilitated by molecular genetics (27). Although a number of studies have shown gene expression of P. gingivalis being regulated by environmental stresses (13,19,35,38,41,46,55), gene expression of P. gingivalis cells in in vivo lesions is not completely understood. Our previous study (54) using a subcutaneous chamber model showed that 10 P. gingivalis proteins were upregulated in host tissues whereas four proteins were downregulated. Among the upregulated proteins, PG1089 (DNAbinding res...

Fimbriae‐mediated outer membrane vesicle production and invasion of Porphyromonas gingivalis

“…; Kondo et al. ) although the mechanism remains to be clarified. Our study also revealed an enrichment of HGP44 (an adhesive domain of gingipains) in vesicles.…”

Adsorption of Components of the Plasma Kinin-Forming System on the Surface ofPorphyromonas gingivalisInvolves Gingipains as the Major Docking Platforms

“…Although several P. gingivalis proteins bearing a conservative C-terminal domain (54,78) are apparently secreted by the PorT/Sov-dependent pathway (38), only the surface exposure of RgpA and Kgp was shown to be essential for HK and FXII binding by P. gingivalis. Interestingly, deficiency of a single gingipain, either RgpA or Kgp, exerted only a modest effect, suggesting that neither gingipain alone is absolutely essential for binding of the contact system proteins but that together, RgpA, RgpB, and Kgp seem to cooperate for maximal sorption of the contact system components (Fig.…”

Proteinaceous determinants of surface colonization in bacteria: bacterial adhesion and biofilm formation from a protein secretion perspective

“…Gliding involves the rapid movement of the semiredundant motility adhesins SprB and RemA along the cell surface (Shrivastava et al, 2013). T9SS-secreted proteins exhibit C-terminal domains (CTDs) considered essential for attachment to the bacterial cell surface by an A-LPS anchor containing anionic polysaccharide repeating units (Kondo et al, 2010; Shoji et al, 2011; Slakeski et al, 2011; Shrivastava et al, 2013). CTD region function as a recognition signal for the T9SS and glycosylation occurs after removal of the CTD region (Shoji et al, 2011; Glew et al, 2012).…”