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Zhao X, Xu C, Qu J, Jin Y, Bai F, Cheng Z, Wu W, Pan X. PitA Controls the H2- and H3-T6SSs through PhoB in Pseudomonas aeruginosa. Appl Environ Microbiol 2023; 89:e0209422. [PMID: 37184394 PMCID: PMC10304775 DOI: 10.1128/aem.02094-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 04/21/2023] [Indexed: 05/16/2023] Open
Abstract
Pseudomonas aeruginosa possesses three type VI secretion systems (T6SSs) that are involved in interspecies competition, internalization into epithelial cells, and virulence. Host-derived mucin glycans regulate the T6SSs through RetS, and attacks from other species activate the H1-T6SS. However, other environmental signals that control the T6SSs remain to be explored. Previously, we determined PitA to be a constitutive phosphate transporter, whose mutation reduces the intracellular phosphate concentration. Here, we demonstrate that mutation in the pitA gene increases the expression of the H2- and H3-T6SS genes and enhances bacterial uptake by A549 cells. We further found that mutation of pitA results in activation of the quorum sensing (QS) systems, which contributes to the upregulation of the H2- and H3-T6SS genes. Overexpression of the phosphate transporter complex genes pstSCAB or knockdown of the phosphate starvation response regulator gene phoB in the ΔpitA mutant reduces the expression of the QS genes and subsequently the H2- and H3-T6SS genes and bacterial internalization. Furthermore, growth of wild-type PA14 in a low-phosphate medium results in upregulation of the QS and H2- and H3-T6SS genes and bacterial internalization compared to those in cells grown in a high-phosphate medium. Deletion of the phoB gene abolished the differences in the expression of the QS and T6SS genes as well as bacterial internalization in the low- and high- phosphate media. Overall, our results elucidate the mechanism of PitA-mediated regulation on the QS system and H2- and H3-T6SSs and reveal a novel pathway that regulates the T6SSs in response to phosphate starvation. IMPORTANCE Pseudomonas aeruginosa is an opportunistic pathogenic bacterium that causes acute and chronic infections in humans. The type VI secretion systems (T6SSs) have been shown to associate with chronic infections. Understanding the mechanism used by the bacteria to sense environmental signals and regulate virulence factors will provide clues for developing novel effective treatment strategies. Here, we demonstrate a relationship between a phosphate transporter and the T6SSs and reveal a novel regulatory pathway that senses phosphate limitation and controls bacterial virulence factors in P. aeruginosa.
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Affiliation(s)
- Xinrui Zhao
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Congjuan Xu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Junze Qu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Fang Bai
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Xiaolei Pan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
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Zhao X, Jin Y, Bai F, Cheng Z, Wu W, Pan X. Pseudomonas aeruginosa Phosphate Transporter PitA (PA4292) Controls Susceptibility to Aminoglycoside Antibiotics by Regulating the Proton Motive Force. Antimicrob Agents Chemother 2022; 66:e0099222. [PMID: 36346250 DOI: 10.1128/aac.00992-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic Gram-negative bacterium that causes nosocomial infections in immunocompromised patients. β-lactam and aminoglycoside antibiotics are commonly used in the treatment of P. aeruginosa infections. Previously, we found that mutation in a PA4292 gene increases bacterial resistance to β-lactam antibiotics. In this study, we demonstrated that mutation in PA4292 increases bacterial susceptibility to aminoglycoside antibiotics. We further found enhanced uptake of tobramycin by the ΔPA4292 mutant, which might be due to an increase of proton motive force (PMF). Sequence analysis revealed PA4292 is homologous to the Escherichia coli phosphate transporter PitA. Mutation of PA4292 indeed reduces intracellular phosphate concentration. We thus named PA4292 as pitA. Although the PMF is enhanced in the ΔpitA mutant, the intracellular ATP concentration is lower than that in the isogenic wild-type strain PA14, which might be due to lack of the ATP synthesis substrate phosphate. Overexpression of the phosphate transporter complex genes pstSCAB in the ΔpitA mutant restores the intracellular phosphate concentration, PMF, ATP synthesis, and aminoglycosides resistance. In addition, growth of wild-type PA14 in a low-phosphate medium resulted in higher PMF and aminoglycoside susceptibility compared to cells grown in a high-phosphate medium. Overall, our results demonstrate the roles of PitA in phosphate transportation and reveal the relationship between intracellular phosphate and aminoglycoside susceptibility.
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Kumari Yadav R, Krishnan V. The adhesive PitA pilus protein from the early dental plaque colonizer Streptococcus oralis: expression, purification, crystallization and X-ray diffraction analysis. Acta Crystallogr F Struct Biol Commun 2020; 76:8-13. [PMID: 31929180 PMCID: PMC6957113 DOI: 10.1107/s2053230x1901642x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 12/05/2019] [Indexed: 11/10/2022] Open
Abstract
PitA is the putative tip adhesin of the pilus islet 2 (PI-2)-encoded sortase-dependent pilus in the Gram-positive Streptococcus oralis, an opportunistic pathogen that often flourishes within the diseased human oral cavity. Early colonization by S. oralis and its interaction with Actinomyces oris seeds the development of oral biofilm or dental plaque. Here, the PI-2 pilus plays a vital role in mediating adherence to host surfaces and other bacteria. A recombinant form of the PitA adhesin has now been produced and crystallized. Owing to the large size (∼100 kDa), flexibility and complicated folding of PitA, obtaining diffraction-quality crystals has been a challenge. However, by the use of limited proteolysis with α-chymotrypsin, the diffraction quality of the PitA crystals was considerably enhanced to 2.16 Å resolution. These crystals belonged to space group P1, with unit-cell parameters a = 61.48, b = 70.87, c = 82.46 Å, α = 80.08, β = 87.02, γ = 87.70°. The anomalous signal from the terbium derivative of α-chymotrypsin-treated PitA crystals prepared with terbium crystallophore (Tb-Xo4) was sufficient to obtain an interpretable electron-density map via terbium SAD phasing.
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Affiliation(s)
- Rajnesh Kumari Yadav
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad 121 001, India
- School of Biotechnology, KIIT University, Odisha 751 024, India
| | - Vengadesan Krishnan
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad 121 001, India
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Malykh EA, Butov IA, Ravcheeva AB, Krylov AA, Mashko SV, Stoynova NV. Specific features of L-histidine production by Escherichia coli concerned with feedback control of AICAR formation and inorganic phosphate/metal transport. Microb Cell Fact 2018; 17:42. [PMID: 29544475 PMCID: PMC5852967 DOI: 10.1186/s12934-018-0890-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 03/08/2018] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND In the L-histidine (His) biosynthetic pathway of Escherichia coli, the first key enzyme, ATP-phosphoribosyltransferase (ATP-PRT, HisG), is subject to different types of inhibition. Eliminating the feedback inhibition of HisG by the His end product is an important step that enables the oversynthesis of His in breeding strains. However, the previously reported feedback inhibition-resistant mutant enzyme from E. coli, HisGE271K, is inhibited by purine nucleotides, particularly ADP and AMP, via competitive inhibition with its ATP substrate. 5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR), which is formed not only during His biosynthesis but also during de novo purine biosynthesis, acts as a natural analog of AMP and substitutes for it in some enzymatic reactions. We hypothesized that AICAR could control its own formation, particularly through the His biosynthetic pathway, by negatively influencing HisG enzymatic activity, which would make preventing ATP-PRT transferase inhibition by AICAR crucial for His overproduction. RESULTS For the first time, both the native E. coli HisG and the previously described feedback-resistant mutant HisGE271K enzymes were shown to be sensitive to inhibition by AICAR, a structural analog of AMP. To circumvent the negative effect that AICAR has on His synthesis, we constructed the new His-producing strain EA83 and demonstrated its improved histidine production. This increased production was particularly associated with the improved conversion of AICAR to ATP due to purH and purA gene overexpression; additionally, the PitA-dependent phosphate/metal (Me2+-Pi) transport system was modified by a pitA gene deletion. This His-producing strain unexpectedly exhibited decreased alkaline phosphatase activity at low Pi concentrations. AICAR was consequently hypothesized inhibit the two-component PhoBR system, which controls Pho regulon gene expression. CONCLUSIONS Inhibition of a key enzyme in the His biosynthetic pathway, HisG, by AICAR, which is formed in this pathway, generates a serious bottleneck during His production. The constructed His-producing strain demonstrated the enhanced expression of genes that encode enzymes involved in the metabolism of AICAR to ATP, which is a substrate of HisG, and thus led to improved His accumulation.
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Affiliation(s)
- Evgeniya A Malykh
- Ajinomoto-Genetika Research Institute, 1-st Dorozny pr., 1-1, Moscow, 117545, Russian Federation
| | - Ivan A Butov
- Ajinomoto-Genetika Research Institute, 1-st Dorozny pr., 1-1, Moscow, 117545, Russian Federation
| | - Anna B Ravcheeva
- Ajinomoto-Genetika Research Institute, 1-st Dorozny pr., 1-1, Moscow, 117545, Russian Federation
| | - Alexander A Krylov
- Ajinomoto-Genetika Research Institute, 1-st Dorozny pr., 1-1, Moscow, 117545, Russian Federation
| | - Sergey V Mashko
- Ajinomoto-Genetika Research Institute, 1-st Dorozny pr., 1-1, Moscow, 117545, Russian Federation
| | - Nataliya V Stoynova
- Ajinomoto-Genetika Research Institute, 1-st Dorozny pr., 1-1, Moscow, 117545, Russian Federation.
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Kelliher JL, Radin JN, Grim KP, Párraga Solórzano PK, Degnan PH, Kehl-Fie TE. Acquisition of the Phosphate Transporter NptA Enhances Staphylococcus aureus Pathogenesis by Improving Phosphate Uptake in Divergent Environments. Infect Immun 2018; 86:e00631-17. [PMID: 29084897 DOI: 10.1128/IAI.00631-17] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 10/24/2017] [Indexed: 12/28/2022] Open
Abstract
During infection, pathogens must obtain all inorganic nutrients, such as phosphate, from the host. Despite the essentiality of phosphate for all forms of life, how Staphylococcus aureus obtains this nutrient during infection is unknown. Differing from Escherichia coli, the paradigm for bacterial phosphate acquisition, which has two inorganic phosphate (Pi) importers, genomic analysis suggested that S. aureus possesses three distinct Pi transporters: PstSCAB, PitA, and NptA. While pitA and nptA are expressed in phosphate-replete media, expression of all three transporters is induced by phosphate limitation. The loss of a single transporter did not affect S. aureus However, disruption of any two systems significantly reduced Pi accumulation and growth in divergent environments. These findings indicate that PstSCAB, PitA, and NptA have overlapping but nonredundant functions, thus expanding the environments in which S. aureus can successfully obtain Pi Consistent with this idea, in a systemic mouse model of disease, loss of any one transporter did not decrease staphylococcal virulence. However, loss of NptA in conjunction with either PstSCAB or PitA significantly reduced the ability of S. aureus to cause infection. These observations suggest that Pi acquisition via NptA is particularly important for the pathogenesis of S. aureus While our analysis suggests that NptA homologs are widely distributed among bacteria, closely related less pathogenic staphylococcal species do not possess this importer. Altogether, these observations indicate that Pi uptake by S. aureus differs from established models and that acquisition of a third transporter enhances the ability of the bacterium to cause infection.
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Elías AO, Abarca MJ, Montes RA, Chasteen TG, Pérez-Donoso JM, Vásquez CC. Tellurite enters Escherichia coli mainly through the PitA phosphate transporter. Microbiologyopen 2012. [PMID: 23189244 PMCID: PMC3501828 DOI: 10.1002/mbo3.26] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Several transporters suspected to be involved in tellurite uptake in Escherichia coli were analyzed. Results showed that the PitA phosphate transporter was related to tellurite uptake. Escherichia coli ΔpitA was approximately four-fold more tolerant to tellurite, and cell viability remained almost unchanged during prolonged exposure to the toxicant as compared with wild type or ΔpitB cells. Notably, reduced thiols (toxicant targets) as well as superoxide dismutase, catalase, and fumarase C activities did not change when exposing the ΔpitA strain to tellurite, suggesting that tellurite-triggered oxidative damage is attenuated in the absence of PitA. After toxicant exposure, remaining extracellular tellurite was higher in E. coli ΔpitA than in control cells. Whereas inductively coupled plasma atomic emission spectrometric studies confirmed that E. coli ΔpitA accumulates ∼50% less tellurite than the other strains under study, tellurite strongly inhibited 32Pi uptake suggesting that the PitA transporter is one of the main responsible for tellurite uptake in this bacterium.
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Affiliation(s)
- Alex O Elías
- Laboratorio de Microbiología Molecular, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile Chile
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