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Jamdar SN, Yadav P, Kulkarni BS, Sudesh, Kumar A, Makde RD. Crystal structure of a newly identified M61 family aminopeptidase with broad substrate specificity that is solely responsible for recycling acidic amino acids. FEBS J 2024. [PMID: 38646733 DOI: 10.1111/febs.17133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 02/10/2024] [Accepted: 03/25/2024] [Indexed: 04/23/2024]
Abstract
Aminopeptidases with varied substrate specificities are involved in different crucial physiological processes of cellular homeostasis. They also have wide applications in food and pharma industries. Within the bacterial cell, broad specificity aminopeptidases primarily participate in the recycling of amino acids by degrading oligopeptides generated via primary proteolysis mediated by cellular ATP-dependent proteases. However, in bacteria, a truly broad specificity enzyme, which can cleave off acidic, basic, Gly and hydrophobic amino acid residues, is extremely rare. Here, we report structure-function of a putative glycyl aminopeptidase (M61xc) from Xanthomonas campestris pv campestris (Xcc) belonging to the M61 peptidase family. The enzyme exhibits broad specificity and cleaves Ala, Leu, Asp, Glu, Met, Ser, Phe, Tyr, Gly, Arg, and Lys at the N terminus, optimally of peptides with a length of 3-7 amino acids. Further, we report the high-resolution crystal structure of M61xc in the apo form (2.1 Å) and bestatin-bound form (1.95 Å), detailing its catalytic and substrate preference mechanisms. Comparative analysis of enzyme activity in crude cell extracts from both wild-type and m61xc-knockout mutant strains of Xcc has elucidated the unique intracellular role of M61xc. This study suggests that M61xc is the exclusive enzyme in these bacteria that is responsible for liberating Asp/Glu residues from the N-termini of peptides. Also, in view of its broad specificity and peptide degradation ability, it could be considered equivalent to M1 or other oligomeric peptidases from families like M17, M18, M42 or S9, who have an important auxiliary role in post-proteasomal protein degradation in prokaryotes.
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Affiliation(s)
- Sahayog N Jamdar
- Food Technology Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Pooja Yadav
- Beamline Development and Application Section, Bhabha Atomic Research Centre, Mumbai, India
| | | | - Sudesh
- Food Technology Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Ashwani Kumar
- Beamline Development and Application Section, Bhabha Atomic Research Centre, Mumbai, India
| | - Ravindra D Makde
- Beamline Development and Application Section, Bhabha Atomic Research Centre, Mumbai, India
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2
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Bhardwaj RG, Khalaf ME, Karched M. Secretome analysis and virulence assessment in Abiotrophia defectiva. J Oral Microbiol 2024; 16:2307067. [PMID: 38352067 PMCID: PMC10863525 DOI: 10.1080/20002297.2024.2307067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 01/11/2024] [Indexed: 02/16/2024] Open
Abstract
Background Abiotrophia defectiva, although infrequently occurring, is a notable cause of culture-negative infective endocarditis with limited research on its virulence. Associated with oral infections such as dental caries, exploring its secretome may provide insights into virulence mechanisms. Our study aimed to analyze and characterize the secretome of A. defectiva strain CCUG 27639. Methods Secretome of A. defectiva was prepared from broth cultures and subjected to mass spectrometry and proteomics for protein identification. Inflammatory potential of the secretome was assessed by ELISA. Results Eighty-four proteins were identified, with diverse subcellular localizations predicted by PSORTb. Notably, 20 were cytoplasmic, 12 cytoplasmic membrane, 5 extracellular, and 9 cell wall-anchored proteins. Bioinformatics tools revealed 54 proteins secreted via the 'Sec' pathway and 8 via a non-classical pathway. Moonlighting functions were found in 23 proteins, with over 20 exhibiting potential virulence properties, including peroxiredoxin and oligopeptide ABC transporter substrate-binding protein. Gene Ontology and KEGG analyses categorized protein sequences in various pathways. STRING analysis revealed functional protein association networks. Cytokine profiling demonstrated significant proinflammatory cytokine release (IL-8, IL-1β, and CCL5) from human PBMCs. Conclusions Our study provides a comprehensive understanding of A. defectiva's secretome, laying the foundation for insights into its pathogenicity.
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Affiliation(s)
- Radhika G Bhardwaj
- Oral Microbiology Research Laboratory, Department of Bioclinical Sciences College of Dentistry, Kuwait University, Safat, Kuwait
| | - Mai E Khalaf
- Department of General Dental Practice, College of Dentistry, Kuwait University, Safat, Kuwait
| | - Maribasappa Karched
- Oral Microbiology Research Laboratory, Department of Bioclinical Sciences College of Dentistry, Kuwait University, Safat, Kuwait
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3
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Sun Y, Shao X, Zhang Y, Han L, Huang J, Xie Y, Liu J, Deng X. Maintenance of tRNA and elongation factors supports T3SS proteins translational elongations in pathogenic bacteria during nutrient starvation. Cell Biosci 2022; 12:147. [PMID: 36064743 PMCID: PMC9446538 DOI: 10.1186/s13578-022-00884-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Accepted: 08/13/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Sufficient nutrition contributes to rapid translational elongation and protein synthesis in eukaryotic cells and prokaryotic bacteria. Fast synthesis and accumulation of type III secretion system (T3SS) proteins conduce to the invasion of pathogenic bacteria into the host cells. However, the translational elongation patterns of T3SS proteins in pathogenic bacteria under T3SS-inducing conditions remain unclear. Here, we report a mechanism of translational elongation of T3SS regulators, effectors and structural protein in four model pathogenic bacteria (Pseudomonas syringae, Pseudomonas aeruginosa, Xanthomonas oryzae and Ralstonia solanacearum) and a clinical isolate (Pseudomonas aeruginosa UCBPP-PA14) under nutrient-limiting conditions. We proposed a luminescence reporter system to quantitatively determine the translational elongation rates (ERs) of T3SS regulators, effectors and structural protein under different nutrient-limiting conditions and culture durations.
Results
The translational ERs of T3SS regulators, effectors and structural protein in these pathogenic bacteria were negatively regulated by the nutrient concentration and culture duration. The translational ERs in 0.5× T3SS-inducing medium were the highest of all tested media. In 1× T3SS-inducing medium, the translational ERs were highest at 0 min and then rapidly decreased. The translational ERs of T3SS regulators, effectors and structural protein were inhibited by tRNA degradation and by reduced levels of elongation factors (EFs).
Conclusions
Rapid translational ER and synthesis of T3SS protein need adequate tRNAs and EFs in nutrient-limiting conditions. Numeric presentation of T3SS translation visually indicates the invasion of bacteria and provides new insights into T3SS expression that can be applied to other pathogenic bacteria.
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Li K, Liao J, Wei M, Qiu S, Wu W, Zhao Y, Wang H, Liu Q, Liu F, Chang C. The Xanthomonas citri Reverse Fitness Deficiency by Activating a Novel β-Glucosidase Under Low Osmostress. Front Microbiol 2022; 13:887967. [PMID: 35586864 PMCID: PMC9108719 DOI: 10.3389/fmicb.2022.887967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 03/17/2022] [Indexed: 11/13/2022] Open
Abstract
Bacteria can withstand various types of environmental osmostress. A sudden rise in osmostress affects bacterial cell growth that is countered by activating special genes. The change of osmostress is generally a slow process under the natural environment. However, the collective response of bacteria to low osmostress remains unknown. This study revealed that the deletion of phoP (ΔphoP) from X. citri significantly compromised the growth and virulence as compared to the wild-type strain. Interestingly, low osmostress reversed physiological deficiencies of X. citri phoP mutant related to bacterial growth and virulence. The results also provided biochemical and genetic evidence that the physiological deficiency of phoP mutant can be reversed by low osmostress induced β-glucosidase (BglS) expression. Based on the data, this study proposes a novel regulatory mechanism of a novel β-glucosidase activation in X. citri through low osmostress to reverse the fitness deficiency.
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Affiliation(s)
- Kaihuai Li
- College of Plant Protection, Integrate Microbiology Research Center, South China Agricultural University, Guangzhou, China
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Jinxing Liao
- College of Plant Protection, Integrate Microbiology Research Center, South China Agricultural University, Guangzhou, China
| | - Ming Wei
- College of Plant Protection, Integrate Microbiology Research Center, South China Agricultural University, Guangzhou, China
| | - Shanxu Qiu
- College of Plant Protection, Integrate Microbiology Research Center, South China Agricultural University, Guangzhou, China
| | - Weiyin Wu
- College of Plant Protection, Integrate Microbiology Research Center, South China Agricultural University, Guangzhou, China
| | - Yancun Zhao
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Haihong Wang
- College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Qiongguang Liu
- College of Plant Protection, Integrate Microbiology Research Center, South China Agricultural University, Guangzhou, China
| | - Fengquan Liu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- *Correspondence: Fengquan Liu,
| | - Changqing Chang
- College of Plant Protection, Integrate Microbiology Research Center, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
- Changqing Chang,
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5
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Pseudomonas aeruginosa C-Terminal Processing Protease CtpA Assembles into a Hexameric Structure That Requires Activation by a Spiral-Shaped Lipoprotein-Binding Partner. mBio 2022; 13:e0368021. [PMID: 35038915 PMCID: PMC8764530 DOI: 10.1128/mbio.03680-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Pseudomonas aeruginosa CtpA is a carboxyl-terminal processing protease that partners with the outer membrane lipoprotein LbcA to degrade at least five cell wall-associated proteins, four of which are cell wall hydrolases. This activity plays an important role in supporting P. aeruginosa virulence in a mouse model of acute pneumonia. However, almost nothing is known about the molecular mechanisms underlying CtpA and LbcA function. Here, we used structural analysis to show that CtpA alone assembles into an inactive hexamer comprising a trimer of dimers, which limits its substrate access and prevents nonspecific degradation. The adaptor protein LbcA is a right-handed open spiral with 11 tetratricopeptide repeats, which might wrap around a substrate to deliver it to CtpA for degradation. By structure-guided mutagenesis and functional assays, we also showed that the interfaces of the CtpA trimer of dimers and an N-terminal helix of LbcA are important for LbcA-mediated substrate degradation by CtpA both in vitro and in vivo. This work improves our understanding of the molecular mechanism of the LbcA-CtpA proteolytic system and reveals some striking differences from the arrangements found in some other bacterial CTPs. IMPORTANCE Carboxyl-terminal processing proteases (CTPs) are found in all three domains of life. In bacteria, some CTPs have been associated with virulence, raising the possibility that they could be therapeutic targets. However, relatively little is known about their molecular mechanisms of action. In Pseudomonas aeruginosa, CtpA supports virulence by working in complex with the outer membrane lipoprotein LbcA to degrade cell wall hydrolases. Here, we report structure-function analyses of CtpA and LbcA, which reveals that CtpA assembles into an inactive hexamer comprising a trimer of dimers. LbcA is monomeric, with the first N-terminal helix important for binding to and activating CtpA, followed by a spiral structure composed of 11 tetratricopeptide repeats, which could wrap around a substrate for delivery to CtpA. This work reveals a unique mutimeric arrangement for a CTP and insight into how the important LbcA-CtpA proteolytic system functions.
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Masoura M, Milner MT, Overton TW, Gkatzionis K, Lund PA. Use of Transposon Directed Insertion-Site Sequencing to Probe the Antibacterial Mechanism of a Model Honey on E. coli K-12. Front Microbiol 2022; 12:803307. [PMID: 35111142 PMCID: PMC8803141 DOI: 10.3389/fmicb.2021.803307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 11/19/2021] [Indexed: 12/13/2022] Open
Abstract
Antimicrobial resistance is an ever-growing health concern worldwide that has created renewed interest in the use of traditional anti-microbial treatments, including honey. However, understanding the underlying mechanism of the anti-microbial action of honey has been hampered due to the complexity of its composition. High throughput genetic tools could assist in understanding this mechanism. In this study, the anti-bacterial mechanism of a model honey, made of sugars, hydrogen peroxide, and gluconic acid, was investigated using genome-wide transposon mutagenesis combined with high-throughput sequencing (TraDIS), with the strain Escherichia coli K-12 MG1655 as the target organism. We identified a number of genes which when mutated caused a severe loss of fitness when cells were exposed to the model honey. These genes encode membrane proteins including those involved in uptake of essential molecules, and components of the electron transport chain. They are enriched for pathways involved in intracellular homeostasis and redox activity. Genes involved in assembly and activity of formate dehydrogenase O (FDH-O) were of particular note. The phenotypes of mutants in a subset of the genes identified were confirmed by phenotypic screening of deletion strains. We also found some genes which when mutated led to enhanced resistance to treatment with the model honey. This study identifies potential synergies between the main honey stressors and provides insights into the global antibacterial mechanism of this natural product.
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Affiliation(s)
- Maria Masoura
- School of Chemical Engineering, University of Birmingham, Birmingham, United Kingdom
- Institute of Microbiology and Infection (IMI), University of Birmingham, Birmingham, United Kingdom
| | - Mathew T. Milner
- Institute of Microbiology and Infection (IMI), University of Birmingham, Birmingham, United Kingdom
| | - Tim W. Overton
- School of Chemical Engineering, University of Birmingham, Birmingham, United Kingdom
| | - Konstantinos Gkatzionis
- School of Chemical Engineering, University of Birmingham, Birmingham, United Kingdom
- Department of Food Science and Nutrition, School of the Environment, University of the Aegean, Lemnos, Greece
| | - Peter A. Lund
- Institute of Microbiology and Infection (IMI), University of Birmingham, Birmingham, United Kingdom
- *Correspondence: Peter A. Lund,
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Wang B, Wu G, Li K, Ling J, Zhao Y, Liu F. A Glycoside Hydrolase Family 99-Like Domain-Containing Protein Modifies Outer Membrane Proteins to Maintain Xanthomonas Pathogenicity and Viability in Stressful Environments. PHYTOPATHOLOGY 2021; 111:929-939. [PMID: 33174820 DOI: 10.1094/phyto-08-20-0327-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Protein glycosylation is an essential process that plays an important role in proteome stability, protein structure, and protein function modulation in eukaryotes. However, in bacteria, especially plant pathogenic bacteria, similar studies are lacking. Here, we investigated the relationship between protein glycosylation and pathogenicity by using Xanthomonas oryzae pv. oryzae, the causal agent of bacterial leaf blight in rice, as a well-defined example. In our previous work, we identified a virulence-related hypothetical protein, PXO_03177, but how this protein regulates X. oryzae pv. oryzae virulence has remained unclear. BLAST analysis showed that most homologous proteins of PXO_03177 are glycoside hydrolase family 99-like domain-containing proteins. In the current study, we found that the outer membrane integrity of ΔPXO_03177 appeared to be disrupted. Extracting the outer membrane proteins (OMPs) and performing comparative proteomics and sodium dodecyl sulphate-polyacrylamide gel electrophoresis gel staining analyses revealed that PXO_03177 deletion altered the protein levels of 13 OMPs. Western blot analyses showed that the protein level and glycosylation modification of PXO_02523, a related OmpA family-like protein, was changed in the ΔPXO_03177 mutant background strain. Additionally, the interaction between PXO_03177 and PXO_02523 was confirmed by coimmunoprecipitation. Both PXO_03177 and PXO_02523 play important roles in regulating pathogen virulence and viability in stressful environments. This work provides the first evidence that protein glycosylation is necessary for the virulence of plant pathogenic bacteria.
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Affiliation(s)
- Bo Wang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, P.R. China
| | - Guichun Wu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, P.R. China
| | - Kaihuai Li
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, P.R. China
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Jun Ling
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, P.R. China
| | - Yancun Zhao
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, P.R. China
| | - Fengquan Liu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, P.R. China
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8
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Heywood A, Lamont IL. Cell envelope proteases and peptidases of Pseudomonas aeruginosa: multiple roles, multiple mechanisms. FEMS Microbiol Rev 2020; 44:857-873. [PMID: 32804218 DOI: 10.1093/femsre/fuaa036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 08/05/2020] [Indexed: 12/15/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative bacterium that is commonly isolated from damp environments. It is also a major opportunistic pathogen, causing a wide range of problematic infections. The cell envelope of P. aeruginosa, comprising the cytoplasmic membrane, periplasmic space, peptidoglycan layer and outer membrane, is critical to the bacteria's ability to adapt and thrive in a wide range of environments. Over 40 proteases and peptidases are located in the P. aeruginosa cell envelope. These enzymes play many crucial roles. They are required for protein secretion out of the cytoplasm to the periplasm, outer membrane, cell surface or the environment; for protein quality control and removal of misfolded proteins; for controlling gene expression, allowing adaptation to environmental changes; for modification and remodelling of peptidoglycan; and for metabolism of small molecules. The key roles of cell envelope proteases in ensuring normal cell functioning have prompted the development of inhibitors targeting some of these enzymes as potential new anti-Pseudomonas therapies. In this review, we summarise the current state of knowledge across the breadth of P. aeruginosa cell envelope proteases and peptidases, with an emphasis on recent findings, and highlight likely future directions in their study.
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Affiliation(s)
- Astra Heywood
- Department of Biochemistry, University of Otago, Dunedin 9054, New Zealand
| | - Iain L Lamont
- Department of Biochemistry, University of Otago, Dunedin 9054, New Zealand
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Li CE, Liao CT, Lo HH, Hsiao YM. Functional Characterization and Transcriptional Analysis of clpP of Xanthomonas campestris pv. campestris. Curr Microbiol 2020; 77:2876-2885. [PMID: 32623486 DOI: 10.1007/s00284-020-02093-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 06/15/2020] [Indexed: 01/24/2023]
Abstract
The caseinolytic protease (Clp) system is essential for survival under stress conditions and for virulence in several pathogenic bacteria. Xanthomonas campestris pv. campestris (Xcc) is a plant pathogen which causes black rot disease in crucifers. In this study, the Xcc clpP gene which is annotated to encode the proteolytic core of Clp was characterized. Mutation of clpP resulted in susceptibility to high temperature and puromycin stresses. Site-directed mutagenesis revealed that S105, H130, and D179 are critical amino acid residues for ClpP function in puromycin tolerance. Inactivation of clpP also revealed an attenuation of virulence on the host plant and a reduction in the production of extracellular cellulase, mannanase, pectinase, and protease. The affected phenotypes of the clpP mutant could be complemented to wild-type levels by the intact clpP gene. Transcriptional analysis revealed that expression of clpP is induced under heat shock condition.
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Affiliation(s)
- Chih-En Li
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, 406, Taiwan
| | - Chao-Tsai Liao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, 406, Taiwan
| | - Hsueh-Hsia Lo
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, 406, Taiwan
| | - Yi-Min Hsiao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, 406, Taiwan.
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Huang WC, Lin CY, Hashimoto M, Wu JJ, Wang MC, Lin WH, Chen CS, Teng CH. The role of the bacterial protease Prc in the uropathogenesis of extraintestinal pathogenic Escherichia coli. J Biomed Sci 2020; 27:14. [PMID: 31900139 PMCID: PMC6941253 DOI: 10.1186/s12929-019-0605-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 12/19/2019] [Indexed: 02/07/2023] Open
Abstract
Background Extraintestinal pathogenic E. coli (ExPEC) remains one of the most prevalent bacterial pathogens that cause extraintestinal infections, including neonatal meningitis, septicemia, and urinary tract (UT) infections (UTIs). Antibiotic therapy has been the conventional treatment for such infections, but its efficacy has decreased due to the emergence of antibiotic-resistant bacteria. Identification and characterization of bacterial factors that contribute to the severity of infection would facilitate the development of novel therapeutic strategies. The ExPEC periplasmic protease Prc contributes to the pathogen’s ability to evade complement-mediated killing in the serum. Here, we further investigated the role of the Prc protease in ExPEC-induced UTIs and the underlying mechanism. Methods The uropathogenic role of Prc was determined in a mouse model of UTIs. Using global quantitative proteomic analyses, we revealed that the expression of FliC and other outer membrane-associated proteins was altered by Prc deficiency. Comparative transcriptome analyses identified that Prc deficiency affected expression of the flagellar regulon and genes that are regulated by five extracytoplasmic signaling systems. Results A mutant ExPEC with a prc deletion was attenuated in bladder and kidney colonization. Global quantitative proteomic analyses of the prc mutant and wild-type ExPEC strains revealed significantly reduced flagellum expression in the absence of Prc, consequently impairing bacterial motility. The prc deletion triggered downregulation of the flhDC operon encoding the master transcriptional regulator of flagellum biogenesis. Overexpressing flhDC restored the prc mutant’s motility and ability to colonize the UT, suggesting that the impaired motility is responsible for attenuated UT colonization of the mutant. Further comparative transcriptome analyses revealed that Prc deficiency activated the σE and RcsCDB signaling pathways. These pathways were responsible for the diminished flhDC expression. Finally, the activation of the RcsCDB system was attributed to the intracellular accumulation of a known Prc substrate Spr in the prc mutant. Spr is a peptidoglycan hydrolase and its accumulation destabilizes the bacterial envelope. Conclusions We demonstrated for the first time that Prc is essential for full ExPEC virulence in UTIs. Our results collectively support the idea that Prc is essential for bacterial envelope integrity, thus explaining how Prc deficiency results in an attenuated ExPEC.
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Affiliation(s)
- Wen-Chun Huang
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chung-Yen Lin
- Institute of Information Science, Academia Sinica, Taipei, Taiwan
| | - Masayuki Hashimoto
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
| | - Jiunn-Jong Wu
- Department of Biotechnology and Laboratory Science in Medicine, School of Biomedical Science and Engineering, National Yang Ming University, Taipei, Taiwan
| | - Ming-Cheng Wang
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Wei-Hung Lin
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chang-Shi Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Ching-Hao Teng
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan. .,Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan. .,Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan.
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11
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Figaj D, Ambroziak P, Przepiora T, Skorko-Glonek J. The Role of Proteases in the Virulence of Plant Pathogenic Bacteria. Int J Mol Sci 2019; 20:ijms20030672. [PMID: 30720762 PMCID: PMC6386880 DOI: 10.3390/ijms20030672] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 01/30/2019] [Accepted: 02/02/2019] [Indexed: 12/17/2022] Open
Abstract
A pathogenic lifestyle is inextricably linked with the constant necessity of facing various challenges exerted by the external environment (both within and outside the host). To successfully colonize the host and establish infection, pathogens have evolved sophisticated systems to combat the host defense mechanisms and also to be able to withstand adverse environmental conditions. Proteases, as crucial components of these systems, are involved in a variety of processes associated with infection. In phytopathogenic bacteria, they play important regulatory roles and modulate the expression and functioning of various virulence factors. Secretory proteases directly help avoid recognition by the plant immune systems, and contribute to the deactivation of the defense response pathways. Finally, proteases are important components of protein quality control systems, and thus enable maintaining homeostasis in stressed bacterial cells. In this review, we discuss the known protease functions and protease-regulated signaling processes associated with virulence of plant pathogenic bacteria.
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Affiliation(s)
- Donata Figaj
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland.
| | - Patrycja Ambroziak
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland.
| | - Tomasz Przepiora
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland.
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12
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Deng CY, Zhang H, Wu Y, Ding LL, Pan Y, Sun ST, Li YJ, Wang L, Qian W. Proteolysis of histidine kinase VgrS inhibits its autophosphorylation and promotes osmostress resistance in Xanthomonas campestris. Nat Commun 2018; 9:4791. [PMID: 30442885 PMCID: PMC6237974 DOI: 10.1038/s41467-018-07228-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 10/18/2018] [Indexed: 11/16/2022] Open
Abstract
In bacterial cells, histidine kinases (HKs) are receptors that monitor environmental and intracellular stimuli. HKs and their cognate response regulators constitute two-component signalling systems (TCSs) that modulate cellular homeostasis through reversible protein phosphorylation. Here the authors show that the plant pathogen Xanthomonas campestris pv. campestris responds to osmostress conditions by regulating the activity of a HK (VgrS) via irreversible, proteolytic modification. This regulation is mediated by a periplasmic, PDZ-domain-containing protease (Prc) that cleaves the N-terminal sensor region of VgrS. Cleavage of VgrS inhibits its autokinase activity and regulates the ability of the cognate response regulator (VgrR) to bind promoters of downstream genes, thus promoting bacterial adaptation to osmostress. Bacterial histidine kinases (HKs) play key roles in the response to stimuli and are regulated by reversible phosphorylation. Here, the authors show that the activity of a HK in the plant pathogen Xanthomonas campestris is modulated by irreversible, proteolytic modification in response to osmostress.
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Affiliation(s)
- Chao-Ying Deng
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Huan Zhang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yao Wu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Li-Li Ding
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yue Pan
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shu-Tao Sun
- Department of Core Facility, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Ya-Jun Li
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,The College of Forestry, Beijing Forestry University, Beijing, 100083, China
| | - Li Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Wei Qian
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
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13
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Abstract
Carboxy-terminal processing proteases (CTPs) occur in all three domains of life. In bacteria, some of them have been associated with virulence. However, the precise roles of bacterial CTPs are poorly understood, and few direct proteolytic substrates have been identified. One bacterial CTP is the CtpA protease of Pseudomonas aeruginosa, which is required for type III secretion system (T3SS) function and for virulence in a mouse model of acute pneumonia. Here, we have investigated the function of CtpA in P. aeruginosa and identified some of the proteins it cleaves. We discovered that CtpA forms a complex with a previously uncharacterized protein, which we have named LbcA (lipoprotein binding partner of CtpA). LbcA is required for CtpA activity in vivo and promotes its activity in vitro. We have also identified four proteolytic substrates of CtpA, all of which are uncharacterized proteins predicted to cleave the peptide cross-links within peptidoglycan. Consistent with this, a ctpA null mutant was found to have fewer peptidoglycan cross-links than the wild type and grew slowly in salt-free medium. Intriguingly, the accumulation of just one of the CtpA substrates was required for some ΔctpA mutant phenotypes, including the defective T3SS. We propose that LbcA-CtpA is a proteolytic complex in the P. aeruginosa cell envelope, which controls the activity of several peptidoglycan cross-link hydrolases by degrading them. Furthermore, based on these and other findings, we suggest that many bacterial CTPs might be similarly controlled by partner proteins as part of a widespread mechanism to control peptidoglycan hydrolase activity. Bacterial carboxy-terminal processing proteases (CTPs) are widely conserved and have been associated with the virulence of several species. However, their roles are poorly understood, and few direct substrates have been identified in any species. Pseudomonas aeruginosa is an important human pathogen in which one CTP, known as CtpA, is required for type III secretion system function and for virulence. This work provides an important advance by showing that CtpA works with a previously uncharacterized binding partner to degrade four substrates. These substrates are all predicted to hydrolyze peptidoglycan cross-links, suggesting that the CtpA complex is an important control mechanism for peptidoglycan hydrolysis. This is likely to emerge as a widespread mechanism used by diverse bacteria to control some of their peptidoglycan hydrolases. This is significant, given the links between CTPs and virulence in several pathogens and the importance of peptidoglycan remodeling to almost all bacterial cells.
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14
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Wang B, Wu G, Zhang Y, Qian G, Liu F. Dissecting the virulence-related functionality and cellular transcription mechanism of a conserved hypothetical protein in Xanthomonas oryzae pv. oryzae. MOLECULAR PLANT PATHOLOGY 2018; 19:1859-1872. [PMID: 29392817 PMCID: PMC6638143 DOI: 10.1111/mpp.12664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 01/23/2018] [Accepted: 01/29/2018] [Indexed: 05/09/2023]
Abstract
Hypothetical proteins without defined functions are largely distributed in all sequenced bacterial genomes. Understanding their potent functionalities is a basic demand for bacteriologists. Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial leaf blight of rice, is one of the model systems for the study of molecular plant pathology. One-quarter of proteins in the genome of this bacterium are defined as hypothetical proteins, but their roles in Xoo pathogenicity are unknown. Here, we generated in-frame deletions for six hypothetical proteins selected from strain PXO99A and found that one of them (PXO_03177) is required for the full virulence of this strain. PXO_03177 is conserved in Xanthomonas, and is predicted to contain two domains relating to polysaccharide synthesis. However, we found that mutation of this gene did not affect the production or modification of extracellular polysaccharides (EPSs) and lipopolysaccharides (LPSs), two major polysaccharides produced by Xoo relating to its infection. Interestingly, we found that inactivation of PXO_03177 significantly impaired biofilm formation and tolerance to sodium dodecyl sulfate (SDS), both of which are considered to play key roles during Xoo infection in rice leaves. These findings thus enable us to define a function for PXO_03177 in the virulence of Xoo. Furthermore, we also found that the global regulator Clp controls the transcription of PXO_03177 by direct binding to its promoter region, presenting the first cellular regulatory pathway for the modulation of expression of this hypothetical protein gene. Our results provide reference information for PXO_03177 homologues in Xanthomonas.
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Affiliation(s)
- Bo Wang
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural UniversityNanjing 210095China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of EducationNanjing 210095China
| | - Guichun Wu
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural UniversityNanjing 210095China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of EducationNanjing 210095China
| | - Yuqiang Zhang
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural UniversityNanjing 210095China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of EducationNanjing 210095China
| | - Guoliang Qian
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural UniversityNanjing 210095China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of EducationNanjing 210095China
| | - Fengquan Liu
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural UniversityNanjing 210095China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of EducationNanjing 210095China
- Institute of Plant Protection, Jiangsu Academy of Agricultural SciencesNanjing 210014China
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15
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Artier J, da Silva Zandonadi F, de Souza Carvalho FM, Pauletti BA, Leme AFP, Carnielli CM, Selistre‐de‐Araujo HS, Bertolini MC, Ferro JA, Belasque Júnior J, de Oliveira JCF, Novo‐Mansur MTM. Comparative proteomic analysis of Xanthomonas citri ssp. citri periplasmic proteins reveals changes in cellular envelope metabolism during in vitro pathogenicity induction. MOLECULAR PLANT PATHOLOGY 2018; 19:143-157. [PMID: 27798950 PMCID: PMC6638008 DOI: 10.1111/mpp.12507] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Citrus canker is a plant disease caused by Gram-negative bacteria from the genus Xanthomonas. The most virulent species is Xanthomonas citri ssp. citri (XAC), which attacks a wide range of citrus hosts. Differential proteomic analysis of the periplasm-enriched fraction was performed for XAC cells grown in pathogenicity-inducing (XAM-M) and pathogenicity-non-inducing (nutrient broth) media using two-dimensional electrophoresis combined with liquid chromatography-tandem mass spectrometry. Amongst the 40 proteins identified, transglycosylase was detected in a highly abundant spot in XAC cells grown under inducing condition. Additional up-regulated proteins related to cellular envelope metabolism included glucose-1-phosphate thymidylyltransferase, dTDP-4-dehydrorhamnose-3,5-epimerase and peptidyl-prolyl cis-trans-isomerase. Phosphoglucomutase and superoxide dismutase proteins, known to be involved in pathogenicity in other Xanthomonas species or organisms, were also detected. Western blot and quantitative real-time polymerase chain reaction analyses for transglycosylase and superoxide dismutase confirmed that these proteins were up-regulated under inducing condition, consistent with the proteomic results. Multiple spots for the 60-kDa chaperonin and glyceraldehyde-3-phosphate dehydrogenase were identified, suggesting the presence of post-translational modifications. We propose that substantial alterations in cellular envelope metabolism occur during the XAC infectious process, which are related to several aspects, from defence against reactive oxygen species to exopolysaccharide synthesis. Our results provide new candidates for virulence-related proteins, whose abundance correlates with the induction of pathogenicity and virulence genes, such as hrpD6, hrpG, hrpB7, hpa1 and hrpX. The results present new potential targets against XAC to be investigated in further functional studies.
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Affiliation(s)
- Juliana Artier
- Laboratório de Bioquímica e Biologia Molecular Aplicada, Departamento de Genética e EvoluçãoUniversidade Federal de São Carlos, UFSCarSão CarlosSP13565‐905Brazil
| | - Flávia da Silva Zandonadi
- Laboratório de Bioquímica e Biologia Molecular Aplicada, Departamento de Genética e EvoluçãoUniversidade Federal de São Carlos, UFSCarSão CarlosSP13565‐905Brazil
| | - Flávia Maria de Souza Carvalho
- Departamento de Tecnologia, Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, UNESPUniversidade Estadual PaulistaJaboticabalSP14884‐900Brazil
| | - Bianca Alves Pauletti
- LNBio, CNPEMLaboratório de Espectrometria de Massas, Laboratório Nacional de BiociênciasCampinasSP13083‐970Brazil
| | - Adriana Franco Paes Leme
- LNBio, CNPEMLaboratório de Espectrometria de Massas, Laboratório Nacional de BiociênciasCampinasSP13083‐970Brazil
| | - Carolina Moretto Carnielli
- Laboratório de Bioquímica e Biologia Molecular Aplicada, Departamento de Genética e EvoluçãoUniversidade Federal de São Carlos, UFSCarSão CarlosSP13565‐905Brazil
| | | | - Maria Célia Bertolini
- Departamento de Bioquímica e Tecnologia Química, Instituto de Química, UNESPUniversidade Estadual PaulistaAraraquaraSP14800‐060Brazil
| | - Jesus Aparecido Ferro
- Departamento de Tecnologia, Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, UNESPUniversidade Estadual PaulistaJaboticabalSP14884‐900Brazil
| | - José Belasque Júnior
- Departamento de Fitopatologia e Nematologia, Escola Superior de Agricultura ‘Luiz de Queiroz’Universidade de São PauloPiracicabaSP13418‐900Brazil
| | - Julio Cezar Franco de Oliveira
- Laboratório de Interações Microbianas, Departamento de Ciências BiológicasUniversidade Federal de São Paulo, UNIFESPDiademaSP09913‐030Brazil
| | - Maria Teresa Marques Novo‐Mansur
- Laboratório de Bioquímica e Biologia Molecular Aplicada, Departamento de Genética e EvoluçãoUniversidade Federal de São Carlos, UFSCarSão CarlosSP13565‐905Brazil
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16
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Structure function relations in PDZ-domain-containing proteins: Implications for protein networks in cellular signalling. J Biosci 2017. [DOI: 10.1007/s12038-017-9727-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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17
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Jiang H, Jiang M, Yang L, Yao P, Ma L, Wang C, Wang H, Qian G, Hu B, Fan J. The Ribosomal Protein RplY Is Required for Pectobacterium carotovorum Virulence and Is Induced by Zantedeschia elliotiana Extract. PHYTOPATHOLOGY 2017; 107:1322-1330. [PMID: 28853642 DOI: 10.1094/phyto-04-17-0161-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Pectobacterium carotovorum subsp. carotovorum strain PccS1, a bacterial pathogen causing soft rot disease of Zantedeschia elliotiana (colored calla), was investigated for virulence genes induced by the host plant. Using a promoter-trap transposon (mariner), we obtained 500 transposon mutants showing kanamycin resistance dependent on extract of Z. elliotiana. One of these mutants, PM86, exhibited attenuated virulence on both Z. elliotiana and Brassica rapa subsp. pekinensis. The growth of PM86 was also reduced in minimal medium (MM), and the reduction was restored by adding plant extract to the MM. The gene containing the insertion site was identified as rplY. The deletion mutant ΔrplY, exhibited reduced virulence, motility and plant cell wall-degrading enzyme production but not biofilm formation. Analysis of gene expression and reporter fusions revealed that the rplY gene in PccS1 is up-regulated at both the transcriptional and the translational levels in the presence of plant extract. Our results suggest that rplY is induced by Z. elliotiana extract and is crucial for virulence in P. carotovorum subsp. carotovorum.
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Affiliation(s)
- Huan Jiang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Mengyi Jiang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Liuke Yang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Peiyan Yao
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Lin Ma
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Chunting Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Huan Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Gouliang Qian
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Baishi Hu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jiaqin Fan
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
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18
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Schatschneider S, Schneider J, Blom J, Létisse F, Niehaus K, Goesmann A, Vorhölter FJ. Systems and synthetic biology perspective of the versatile plant-pathogenic and polysaccharide-producing bacterium Xanthomonas campestris. Microbiology (Reading) 2017; 163:1117-1144. [DOI: 10.1099/mic.0.000473] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Sarah Schatschneider
- Abteilung für Proteom und Metabolomforschung, Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Bielefeld, Germany
- Present address: Evonik Nutrition and Care GmbH, Kantstr. 2, 33790 Halle-Künsebeck, Germany
| | - Jessica Schneider
- Bioinformatics Resource Facility, Centrum für Biotechnologie, Universität Bielefeld, Germany
- Present address: Evonik Nutrition and Care GmbH, Kantstr. 2, 33790 Halle-Künsebeck, Germany
| | - Jochen Blom
- Bioinformatics and Systems Biology, Justus-Liebig-University Gießen, Germany
| | - Fabien Létisse
- LISBP, Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | - Karsten Niehaus
- Abteilung für Proteom und Metabolomforschung, Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Bielefeld, Germany
| | - Alexander Goesmann
- Bioinformatics and Systems Biology, Justus-Liebig-University Gießen, Germany
| | - Frank-Jörg Vorhölter
- Institut für Genomforschung und Systembiologie, Centrum für Biotechnology (CeBiTec), Universität Bielefeld, Bielefeld, Germany
- Present address: MVZ Dr. Eberhard & Partner Dortmund, Dortmund, Germany
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19
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An Essential Regulatory System Originating from Polygenic Transcriptional Rewiring of PhoP-PhoQ of Xanthomonas campestris. Genetics 2017; 206:2207-2223. [PMID: 28550013 DOI: 10.1534/genetics.117.200204] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 05/22/2017] [Indexed: 01/06/2023] Open
Abstract
How essential, regulatory genes originate and evolve is intriguing because mutations of these genes not only lead to lethality in organisms, but also have pleiotropic effects since they control the expression of multiple downstream genes. Therefore, the evolution of essential, regulatory genes is not only determined by genetic variations of their own sequences, but also by the biological function of downstream genes and molecular mechanisms of regulation. To understand the origin of essential, regulatory genes, experimental dissection of the complete regulatory cascade is needed. Here, we provide genetic evidences to reveal that PhoP-PhoQ is an essential two-component signal transduction system in the gram-negative bacterium Xanthomonas campestris, but that its orthologs in other bacteria belonging to Proteobacteria are nonessential. Mutational, biochemical, and chromatin immunoprecipitation together with high-throughput sequencing analyses revealed that phoP and phoQ of X. campestris and its close relative Pseudomonas aeruginosa are replaceable, and that the consensus binding motifs of the transcription factor PhoP are also highly conserved. PhoP Xcc in X. campestris regulates the transcription of a number of essential, structural genes by directly binding to cis-regulatory elements (CREs); however, these CREs are lacking in the orthologous essential, structural genes in P. aeruginosa, and thus the regulatory relationships between PhoP Pae and these downstream essential genes are disassociated. Our findings suggested that the recruitment of regulatory proteins by critical structural genes via transcription factor-CRE rewiring is a driving force in the origin and functional divergence of essential, regulatory genes.
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Wang L, Pan Y, Yuan ZH, Zhang H, Peng BY, Wang FF, Qian W. Two-Component Signaling System VgrRS Directly Senses Extracytoplasmic and Intracellular Iron to Control Bacterial Adaptation under Iron Depleted Stress. PLoS Pathog 2016; 12:e1006133. [PMID: 28036380 PMCID: PMC5231390 DOI: 10.1371/journal.ppat.1006133] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 01/12/2017] [Accepted: 12/16/2016] [Indexed: 12/02/2022] Open
Abstract
Both iron starvation and excess are detrimental to cellular life, especially for animal and plant pathogens since they always live in iron-limited environments produced by host immune responses. However, how organisms sense and respond to iron is incompletely understood. Herein, we reveal that in the phytopathogenic bacterium Xanthomonas campestris pv. campestris, VgrS (also named ColS) is a membrane-bound receptor histidine kinase that senses extracytoplasmic iron limitation in the periplasm, while its cognate response regulator, VgrR (ColR), detects intracellular iron excess. Under iron-depleted conditions, dissociation of Fe3+ from the periplasmic sensor region of VgrS activates the VgrS autophosphorylation and subsequent phosphotransfer to VgrR, an OmpR-family transcription factor that regulates bacterial responses to take up iron. VgrR-VgrS regulon and the consensus DNA binding motif of the transcription factor VgrR were dissected by comparative proteomic and ChIP-seq analyses, which revealed that in reacting to iron-depleted environments, VgrR directly or indirectly controls the expressions of hundreds of genes that are involved in various physiological cascades, especially those associated with iron-uptake. Among them, we demonstrated that the phosphorylated VgrR tightly represses the transcription of a special TonB-dependent receptor gene, tdvA. This regulation is a critical prerequisite for efficient iron uptake and bacterial virulence since activation of tdvA transcription is detrimental to these processes. When the intracellular iron accumulates, the VgrR-Fe2+ interaction dissociates not only the binding between VgrR and the tdvA promoter, but also the interaction between VgrR and VgrS. This relieves the repression in tdvA transcription to impede continuous iron uptake and avoids possible toxic effects of excessive iron accumulation. Our results revealed a signaling system that directly senses both extracytoplasmic and intracellular iron to modulate bacterial iron homeostasis. The biological function of iron is like a “double-edge sword” to all cellular life since iron starvation or iron excess leads to cell death. For animal and plant pathogens, they have to compete for iron with their hosts since iron-limitation generally is an immune response against microbial infection. However, how pathogens detect extracellular and intracellular iron concentrations remains unclear. Here we show that a plant bacterial pathogen employs a membrane-bound sensor histidine kinase, VgrS, to directly detect extracytoplasmic iron starvation and activate iron uptake accordingly. As a prerequisite, VgrS phosphorylates cognate VgrR to shut down the transcription of a downstream gene, tdvA, whose expression is harmful to absorb iron and bacterial virulence. However, as intracellular iron concentration increases, the ferrous iron binds to VgrR to release its repression on the tdvA transcription, which results in the block of continuous iron uptake to avoid toxic effect of the metal. Therefore, VgrS and VgrR detect extracytoplasmic and intracellular iron, respectively, and systematically modulate cellular homeostasis to promote bacterial survival in iron-depleted environments, such as in host plant.
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Affiliation(s)
- Li Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yue Pan
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- School of Biological Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zhi-Hui Yuan
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- School of Biological Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Huan Zhang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- School of Biological Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Bao-Yu Peng
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- School of Biological Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Fang-Fang Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Wei Qian
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- * E-mail:
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21
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Liao CT, Liu YF, Chiang YC, Lo HH, Du SC, Hsu PC, Hsiao YM. Functional characterization and transcriptome analysis reveal multiple roles for prc in the pathogenicity of the black rot pathogen Xanthomonas campestris pv. campestris. Res Microbiol 2016; 167:299-312. [PMID: 26804425 DOI: 10.1016/j.resmic.2016.01.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 12/29/2015] [Accepted: 01/06/2016] [Indexed: 10/22/2022]
Abstract
Gram-negative phytopathogenic Xanthomonas campestris pv. campestris (Xcc) is the causal agent of black rot in crucifers. The ability of Xcc to incite this disease in plants depends on a number of factors, including exopolysaccharides, extracellular enzymes and biofilm production. In this study, transposon mutagenesis led to identification of the prc gene, encoding a tail-specific protease, which plays a role in Xcc pathogenesis. Mutation of prc resulted in decreased virulence, extracellular protease production and bacterial attachment, with restoration to the levels of wild type by the intact prc gene. From subsequent quantitative RT-PCR analysis and reporter assay, the major extracellular protease gene prt1, biofilm-related gene galE encoding a UDP-galactose 4-epimerase and two putative adhesin genes (yapH and XC_4290 encoding autotransporter-like protein H and hemagglutinin, respectively) were found to be reduced in the prc mutant. Results of transcriptome profiling of Xcc wild type and prc mutant by RNA sequencing (RNA-Seq) showed that mutation of prc in Xcc leads to alteration in the transcriptional levels (more than twofold) of 91 genes. These differentially expressed genes were associated with a wide range of biological functions such as carbohydrate transport and metabolism, cell wall/membrane biogenesis, posttranslational modification, protein turnover and chaperones, inorganic ion transport and metabolism and signal transduction mechanisms. The results of this study facilitate the functional understanding of and provide new information about the regulatory role of prc.
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Affiliation(s)
- Chao-Tsai Liao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
| | - Yu-Fan Liu
- Department of Biomedical Sciences, Chung Shan Medical University, Taichung 402, Taiwan.
| | - Ying-Chuan Chiang
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
| | - Hsueh-Hsia Lo
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
| | - Shin-Chiao Du
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
| | - Pei-Chi Hsu
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
| | - Yi-Min Hsiao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
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22
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Chen P, Yang W, Tian Y, Sun S, Chen G, Zhang C, Ma F, Xun Y, Shi L, Yang C, Zhao L, Zhou Y, Du H. Electron Transfer Flavoprotein Subunit Beta Is a Candidate Endothelial Cell Autoantigen in Behçet's Disease. PLoS One 2015; 10:e0124760. [PMID: 25915519 PMCID: PMC4410958 DOI: 10.1371/journal.pone.0124760] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Accepted: 03/05/2015] [Indexed: 01/10/2023] Open
Abstract
Behçet’s disease (BD) is a chronic inflammatory disease with multisystem involvement, and it is listed as a rare disease in the United States but is common in the Middle East, China, and Japan. The aim of this study was to identify novel autoantigens in Chinese patients with BD. First, the candidate autoantigens were screened by Western blotting, and the sequences of putative antigens were identified by LC-MALDI-TOF/TOF mass spectrometry. Next, the screened protein was cloned, expressed and purified. Then, an optimized ELISA was developed, and the serological criteria were evaluated using a large number of confirmed patients. One antigen with a molecular weight of approximately 28 kDa was identified as electron transfer flavoprotein subunit beta (ETFB). Positive reactivity was detected in recombinant human ETFB sera from 38 of 92 BD patients (41 %) and 1 of 90 healthy controls (1 %).
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Affiliation(s)
- Peng Chen
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Weikang Yang
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yaping Tian
- Department of Clinical Biochemistry, Chinese PLA General Hospital, Beijing, 100853, China
| | - Shutao Sun
- Core Facility, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Guangyu Chen
- ImmunoHunt Corporation, 139 Fengtai Rd, Beijing, 100071, China
| | - ChunYan Zhang
- Department of Clinical Biochemistry, Chinese PLA General Hospital, Beijing, 100853, China
| | - Fuxin Ma
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yiping Xun
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Lili Shi
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Chunhe Yang
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Lanqing Zhao
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yabin Zhou
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Hongwu Du
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
- * E-mail:
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