The gingipains are also responsible for a number of necessary functions related to host invasion and colonization. Rgp gingipains are necessary for adhesion and invasion as they processed precursor proteins of long fimbriae. The "P. gingivalis" genes encoding RgpA, Kgp, and hemagglutinin A (HagA) were strongly expressed after incubation with "T. denticola". The hemagglutinin adhesion domain-containing proteins act to increase adhesive capacities of "P. gingivalis" with other bacterial species. They are also associated with coordinating the integrity of the biofilm in the developing and maturation phase. Lys- gingipains (Kgp) can bind to immobilized matrix proteins fibrinogen and fibronectin and may have a role in host colonization.