FIG. 7.

Gingipain-mediated adhesion and detachment of P. gingivalis to epithelial cells. We hypothesize that adhesion is mediated by gingipain adhesin peptides localized at the surface of the outer membrane and in membrane vesicles. Rgp catalytic activities, either noncovalently linked with adhesin domains or as soluble proteins, modulate adhesion through digestion of binding substrate. With the parent strain, ATCC 33277, the monolayer adhesion assay measures the net reaction of bacterial attachment to and detachment from receptors or extracellular matrix proteins at the epithelial cell surface. When catalytic activity is reduced by mutation (KDP112), the assay measures the large number of bacteria that attach (via Kgp or HagA adhesin peptides) and accumulate on the monolayers but do not detach or do so very slowly.