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

Abstract

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.

Controlling Porphyromonas gingivalis requires Vim

“…In all, as observed by mass spectrometry of the outer membrane fraction of the vimA mutant, 20 proteins were aberrantly expressed and nine proteins were missing, indicating that VimA plays a role in the glycosylation and anchorage of surface proteins. These results are consistent with previous reports from this group (Vanterpool et al, 2006) showing that VimA also regulates gingipain activity, as there is a late onset of gingipain activity in the vimA mutant. Kgp and Rgp activity in exponential growth phase is 80 % less than that of the wild-type.…”

Por Secretion System of Porphyromonas gingivalis

“…These gingipain adhesin complexes are anchored by cell surface polysaccharides. The porR related to the biosynthesis of APS 12 , vimA 13 , vimE, vimF putative glycosyltransferase 14 , rfa related to the biosynthesis of lipopolysaccharides LPS and APS 15 , gtfB glycosyltransferase 16 , and PG1051 putative O antigen ligase 17 genes were identified as being associated with the biosynthesis of LPS and or cell surface polysaccharides that can function as anchorage points for gingipain adhesin complexes. Gingipain activity was detected in the supernatant but not in intact cells.…”

Gingipain-dependent interactions with the host are important for survival of Porphyromonas gingivalis

“…In in vivo experiments using a mouse model, the vimA-defective mutant (P. gingivalis FLL92) was dramatically reduced in virulence when compared with wild-type W83 strain (1). We have also demonstrated that VimA interacts with the gingipains and other proteins known to be associated with sugar metabolism and protease maturation and is not cleaved by purified RgpB (216). In our bioinformatic studies, VimA appears to be a unique protein that lacks DNA binding motifs or known enzyme domains.…”

“…In our bioinformatic studies, VimA appears to be a unique protein that lacks DNA binding motifs or known enzyme domains. It may be a putative membrane protein and the C-terminus may also have a putative protein binding domain (216). These data suggest that VimA may be part of a protein complex that is involved in gingipain biogenesis/glycosylation (Figure 1).…”

“…In protein-protein interaction studies, the VimA protein was shown to interact with gingipains and other proteins including high temperature requirement A (HtrA) (216). In several organisms, including bacteria, yeast, plant, and humans, HtrA is considered an important factor that is involved in protein folding and maturation as well as in the degradation of proteins that are misfolded (160).…”