VimA is part of the maturation pathway for the major gingipains of Porphyromonas gingivalis W83

The authors have shown previously that the vimA gene, which is part of the bcp-recA-vimA operon, plays an important role in protease activation in Porphyromonas gingivalis. The gingipain RgpB proenzyme is secreted in the vimA-defective mutant P. gingivalis FLL92. An important question that is raised is whether the vimA gene product could directly interact with the proteases for their activation or regulate a pathway responsible for protease activation. To further study the mechanism(s) of VimA-dependent protease activation, the vimA gene product was further characterized. A 39 kDa protein consistent with the size of the predicted VimA protein was purified. In protein-protein interaction studies, the VimA protein was shown to interact with gingipains RgpA, RgpB and Kgp. Immune sera from mice immunized with P. gingivalis immunoreacted with the purified VimA protein. Taken together, these data suggest an interaction of VimA with the gingipains and further confirm the role of this protein in their regulation or maturation.