Characterization of a bacterial tyrosine kinase in Porphyromonas gingivalis involved in polymicrobial synergy

Abstract

Interspecies communication between Porphyromonas gingivalis and Streptococcus gordonii underlies the development of synergistic dual species communities. Contact with S. gordonii initiates signal transduction within P. gingivalis that is based on protein tyrosine (de)phosphorylation. In this study, we characterize a bacterial tyrosine (BY) kinase (designated Ptk1) of P. gingivalis and demonstrate its involvement in interspecies signaling. Ptk1 can utilize ATP for autophosphorylation and is dephosphorylated by the P. gingivalis tyrosine phosphatase, Ltp1. Community development with S. gordonii is severely abrogated in a ptk1 mutant of P. gingivalis, indicating that tyrosine kinase activity is required for maximal polymicrobial synergy. Ptk1 controls the levels of the transcriptional regulator CdhR and the fimbrial adhesin Mfa1 which mediates binding to S. gordonii. The ptk1 gene is in an operon with two genes involved in exopolysaccharide synthesis, and similar to other BY kinases, Ptk1 is necessary for exopolysaccharide production in P. gingivalis. Ptk1 can phosphorylate the capsule related proteins PGN_0224, a UDP-acetyl-mannosamine dehydrogenase, and PGN_0613, a UDP-glucose dehydrogenase, in P. gingivalis. Knockout of ptk1 in an encapsulated strain of P. gingivalis resulted in loss of capsule production. Collectively these results demonstrate that the P. gingivalis Ptk1 BY kinase regulates interspecies communication and controls heterotypic community development with S. gordonii through adjusting the levels of the Mfa1 adhesin and exopolysaccharide.

Deletion of a 77-Base-Pair Inverted Repeat Element Alters the Synthesis of Surface Polysaccharides in Porphyromonas gingivalis

“…In the ltp1 deletion mutant, the expression of PG0106 and PG0116, which are located in the K-antigen locus, is downregulated, while porR (PG1138), porS (PG1137), wbbL (PG1140), a putative rhamnosyltransferase, PG0436, a predicted capsular polysaccharide transport protein, and rfbD (PG1561), a putative dTDP-4-dehydrorhamnose-3,5-epimerase, were found to be upregulated (22), indicating an underlying mechanism of repression. Just recently, Ltp1 was shown to inactivate (dephosphorylate) the tyrosine kinase Ptk1, which in turn was shown to control levels of exopolysaccharide production in both strain 33277 and W83 (24), showing that this tyrosine kinase modulates production and export of extracellular polysaccharide in P. gingivalis. The second regulatory mechanism that has been identified is the DNA-BII protein HU ␤-subunit (PG0121); specifically, genes in both the K-antigen synthesis locus and the A-LPS locus are downregulated in a PG0121 mutant (25,26).…”

The role of kinases and phosphatases in the pathobiology of porphyromonas gingivalis.

“…Previous studies discovered that the P. gingivalis protein PGN_1524 exhibited homology to a tyrosine kinase [55,109]. This predicted tyrosine kinase was later confirmed and as the protein was named P. gingivalis tyrosine kinase-1 (Ptk1).…”

“…FimA fimbriae mediate attachment to a number of host surfaces and stimulate expression of various inflammatory cytokines such as TNF, IL-6 and IL-1, in epithelial cells, monocytes, macrophages and endothelial cells [54]. The Mfa fimbriae mediate attachment to other oral biofilm bacteria [55], and contribute to auto-aggregation and monotypic biofilm formation [56,57]. Mfa1 can also selectively engage the dendritic cell (DC) C-type lectin DC-SIGN, leading to evasion of antibacterial autophagy and lysosome fusion, and intracellular persistence in myeloid DCs [58], properties that may contribute to survival in vivo.…”

“…The catalytically active cytoplasmic fragment Ptk1:541-821 [55] was incubated with 0.5 mmol/L ATP and polyGlu:Tyr (4:1 ratio; 200 µg/mL) for 15 min. Following incubation, the level of fluorescence intensity was measured using a Victor X1 plate reader.…”

Porphyromonas gingivalis infection in gestational diabetes mellitus and survival in tobacco smokers.

“…PGN_1524 encodes a tyrosine kinase which is required for secretion of extracellular polysaccharide and biofilm formation with S. gordonii [350]. Bacterial kinases have also been shown to be involved in stress responses, antibiotic resistance, and DNA metabolism [351][352][353].…”