Glucose-Binding of Periplasmic Protein GltB Activates GtrS-GltR Two-Component System in Pseudomonas aeruginosa

Abstract

A two-component system GtrS-GltR is required for glucose transport activity in P. aeruginosa and plays a key role during P. aeruginosa-host interactions. However, the mechanism of action of GtrS-GltR has not been definitively established. Here, we show that gltB, which encodes a periplasmic glucose binding protein, is essential for the glucose-induced activation of GtrS-GltR in P. aeruginosa. We determined that GltB is capable of binding to membrane regulatory proteins including GtrS, the sensor kinase of the GtrS-GltR TCS. We observed that alanine substitution of glucose-binding residues abolishes the ability of GltB to promote the activation of GtrS-GltR. Importantly, like the gtrS deletion mutant, gltB deletion mutant showed attenuated virulence in both Drosophila melanogaster and mouse models of infection. In addition, using CHIP-seq experiments, we showed that the promoter of gltB is the major in vivo target of GltR. Collectively, these data suggest that periplasmic binding protein GltB and GtrS-GltR TCS form a complex regulatory circuit that regulates the virulence of P. aeruginosa in response to glucose.

Determination of the Two-Component Systems regulatory network reveals core and accessory regulations across Pseudomonas aeruginosa lineages

“…The comparison to this set extracted from 22 previous studies and composed of 59 known binding sites concerning 21 RRs showed that the vast majority were effectively retrieved, often resulting in very highly enriched peaks (Figure S2), further validating our approach. We then compared our results to the previously reported ChIP-seq studies on RRs for which we detected binding sites (PhoB, GacA, GltR, PhoP, CzcR, DsbR and BfmR) (Bielecki et al, 2015;Fan et al, 2021;Huang et al, 2019;Xu et al, 2021;Yang et al, 2021;Yu et al, 2021). Here again, there was a strong overlap in detected binding sites between the DAP-seq data and the six different ChIP-seq studies, as well as highly similar identified DNA motifs (Figure S3).…”

“…Peak lists from ChIP-seq experiments with PhoB, GacA, CzcR, GltR, PhoP, DsbR and BfmR were used to retrieve all peak summit locations (Bielecki et al, 2015;Fan et al, 2021;Huang et al, 2019;Xu et al, 2021;Yang et al, 2021;Yu et al, 2021). Peak summit positions were averaged between replicates and used to infer gene targets using the genome-wide promoter regions defined above with the Intersect tool from BEDTools (Quinlan and Hall, 2010) on the corresponding genomes: PAO1 (Fan et al, 2021;Huang et al, 2019;Xu et al, 2021;Yu et al, 2021) or PA14 (Bielecki et al, 2015;Yang et al, 2021). For DNA motif determination, peak regions were extended by 50bp on each side of the summits and retrieved using the GetFastaBed tool from BEDTools (Quinlan and Hall, 2010).…”

“…However, while bringing new information on selected phenotypes, this approach does not globally address direct RR-target regulatory interactions. Among all RRs encoded in the PAO1 genome, 51 are predicted TFs and the binding sites of only 8 of them (GacA, AlgR, PhoB, PhoP, CzcR, GltR, DsbR and BfmR) have been determined at a genome scale so far (Bielecki et al, 2015;Fan et al, 2021;Huang et al, 2019;Xu et al, 2021;Yang et al, 2021;Yu et al, 2021).…”

Genome-Wide Mapping Reveals Complex Regulatory Activities of BfmR in Pseudomonas aeruginosa

“…The Western blot analysis were performed as described previously with some modifications [42][43][44]. Generally, to examine the production of fusion proteins (i.e., p-PhoB-Flag, p-(D)-PhoB-Flag) in P. aeruginosa, overnight LPM cultures of the indicated strains were diluted to OD 600 ≈ 0.05 with fresh LPM medium.…”

Signal binding at both modules of its dCache domain enables the McpA chemoreceptor of Bacillus velezensis to sense different ligands

“…The response of several Escherichia coli chemoreceptors to sugars is based on the recognition of sugar-loaded SBPs ( 11 ). In addition, PctA of P. aeruginosa was shown to sense glucose through the periplasmic ligand binding protein, GltB ( 48 ). Therefore, our finding that dCache chemoreceptor McpA can directly bind sugars through a combination of both pockets may serve as a reference for analogous studies for sugar chemotaxis in bacteria.…”