1
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Morreale DP, Porsch EA, Kern BK, St Geme JW, Planet PJ. Acquisition, co-option, and duplication of the rtx toxin system and the emergence of virulence in Kingella. Nat Commun 2023; 14:4281. [PMID: 37460464 DOI: 10.1038/s41467-023-39939-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 07/04/2023] [Indexed: 07/20/2023] Open
Abstract
The bacterial genus Kingella includes two pathogenic species, namely Kingella kingae and Kingella negevensis, as well as strictly commensal species. Both K. kingae and K. negevensis secrete a toxin called RtxA that is absent in the commensal species. Here we present a phylogenomic study of the genus Kingella, including new genomic sequences for 88 clinical isolates, genotyping of another 131 global isolates, and analysis of 52 available genomes. The phylogenetic evidence supports that the toxin-encoding operon rtxCA was acquired by a common ancestor of the pathogenic Kingella species, and that a preexisting type-I secretion system was co-opted for toxin export. Subsequent genomic reorganization distributed the toxin machinery across two loci, with 30-35% of K. kingae strains containing two copies of the rtxA toxin gene. The rtxA duplication is largely clonal and is associated with invasive disease. Assays with isogenic strains show that a single copy of rtxA is associated with reduced cytotoxicity in vitro. Thus, our study identifies key steps in the evolutionary transition from commensal to pathogen, including horizontal gene transfer, co-option of an existing secretion system, and gene duplication.
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Affiliation(s)
- Daniel P Morreale
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Eric A Porsch
- Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Brad K Kern
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Joseph W St Geme
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Paul J Planet
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, PA, USA.
- Comparative Genomics, American Museum of Natural History, New York, NY, USA.
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2
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Mullally CA, Mikucki A, Wise MJ, Kahler CM. Modelling evolutionary pathways for commensalism and hypervirulence in Neisseria meningitidis. Microb Genom 2021; 7. [PMID: 34704920 PMCID: PMC8627216 DOI: 10.1099/mgen.0.000662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Neisseria meningitidis, the meningococcus, resides exclusively in humans and causes invasive meningococcal disease (IMD). The population of N. meningitidis is structured into stable clonal complexes by limited horizontal recombination in this naturally transformable species. N. meningitidis is an opportunistic pathogen, with some clonal complexes, such as cc53, effectively acting as commensal colonizers, while other genetic lineages, such as cc11, are rarely colonizers but are over-represented in IMD and are termed hypervirulent. This study examined theoretical evolutionary pathways for pathogenic and commensal lineages by examining the prevalence of horizontally acquired genomic islands (GIs) and loss-of-function (LOF) mutations. Using a collection of 4850 genomes from the BIGSdb database, we identified 82 GIs in the pan-genome of 11 lineages (10 hypervirulent and one commensal lineage). A new computational tool, Phaser, was used to identify frameshift mutations, which were examined for statistically significant association with genetic lineage. Phaser identified a total of 144 frameshift loci of which 105 were shown to have a statistically significant non-random distribution in phase status. The 82 GIs, but not the LOF loci, were associated with genetic lineage and invasiveness using the disease carriage ratio metric. These observations have been integrated into a new model that infers the early events of the evolution of the human adapted meningococcus. These pathways are enriched for GIs that are involved in modulating attachment to the host, growth rate, iron uptake and toxin expression which are proposed to increase competition within the meningococcal population for the limited environmental niche of the human nasopharynx. We surmise that competition for the host mucosal surface with the nasopharyngeal microbiome has led to the selection of isolates with traits that enable access to cell types (non-phagocytic and phagocytic) in the submucosal tissues leading to an increased risk for IMD.
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Affiliation(s)
- Christopher A. Mullally
- The Marshall Center for Infectious Diseases Research and Training, School of Biomedical Science, University of Western Australia, Perth, Australia
| | - August Mikucki
- The Marshall Center for Infectious Diseases Research and Training, School of Biomedical Science, University of Western Australia, Perth, Australia
| | - Michael J. Wise
- The Marshall Center for Infectious Diseases Research and Training, School of Biomedical Science, University of Western Australia, Perth, Australia
- School of Physics, Mathematics and Computing, University of Western Australia, Perth, Australia
| | - Charlene M. Kahler
- The Marshall Center for Infectious Diseases Research and Training, School of Biomedical Science, University of Western Australia, Perth, Australia
- Telethon Kids Institute, Perth Children’s Hospital, Perth, Australia
- *Correspondence: Charlene M. Kahler,
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3
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Abstract
The Ca2+-dependent clip-and-link activity of large repeat-in-toxin (RTX) proteins is an exceptional posttranslational process in which an internal domain called a self-processing module (SPM) mediates Ca2+-dependent processing of a highly specific aspartate-proline (Asp-Pro) peptide bond and covalent linkage of the released aspartyl to an adjacent lysine residue through an isopeptide bond. Here, we report the solution structures of the Ca2+-loaded SPM (Ca-SPM) defining the mechanism of the autocatalytic cleavage of the Asp414-Pro415 peptide bond of the Neisseria meningitidis FrpC exoprotein. Moreover, deletion of the SPM domain in the ApxIVA protein, the FrpC homolog of Actinobacillus pleuropneumoniae, resulted in attenuation of virulence of the bacterium in a pig infection model, indicating that the Ca2+-dependent clip-and-link activity plays a role in the virulence of Gram-negative pathogens. The posttranslational Ca2+-dependent “clip-and-link” activity of large repeat-in-toxin (RTX) proteins starts by Ca2+-dependent structural rearrangement of a highly conserved self-processing module (SPM). Subsequently, an internal aspartate-proline (Asp-Pro) peptide bond at the N-terminal end of SPM breaks, and the liberated C-terminal aspartyl residue can react with a free ε-amino group of an adjacent lysine residue to form a new isopeptide bond. Here, we report a solution structure of the calcium-loaded SPM (Ca-SPM) derived from the FrpC protein of Neisseria meningitidis. The Ca-SPM structure defines a unique protein architecture and provides structural insight into the autocatalytic cleavage of the Asp-Pro peptide bond through a “twisted-amide” activation. Furthermore, in-frame deletion of the SPM domain from the ApxIVA protein of Actinobacillus pleuropneumoniae attenuated the virulence of this porcine pathogen in a pig respiratory challenge model. We hypothesize that the Ca2+-dependent clip-and-link activity represents an unconventional strategy for Gram-negative pathogens to adhere to the host target cell surface.
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4
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Bayer-Santos E, Cenens W, Matsuyama BY, Oka GU, Di Sessa G, Mininel IDV, Alves TL, Farah CS. The opportunistic pathogen Stenotrophomonas maltophilia utilizes a type IV secretion system for interbacterial killing. PLoS Pathog 2019; 15:e1007651. [PMID: 31513674 PMCID: PMC6759196 DOI: 10.1371/journal.ppat.1007651] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 09/24/2019] [Accepted: 08/09/2019] [Indexed: 12/11/2022] Open
Abstract
Bacterial type IV secretion systems (T4SS) are a highly diversified but evolutionarily related family of macromolecule transporters that can secrete proteins and DNA into the extracellular medium or into target cells. It was recently shown that a subtype of T4SS harboured by the plant pathogen Xanthomonas citri transfers toxins into target cells. Here, we show that a similar T4SS from the multi-drug-resistant opportunistic pathogen Stenotrophomonas maltophilia is proficient in killing competitor bacterial species. T4SS-dependent duelling between S. maltophilia and X. citri was observed by time-lapse fluorescence microscopy. A bioinformatic search of the S. maltophilia K279a genome for proteins containing a C-terminal domain conserved in X. citri T4SS effectors (XVIPCD) identified twelve putative effectors and their cognate immunity proteins. We selected a putative S. maltophilia effector with unknown function (Smlt3024) for further characterization and confirmed that it is indeed secreted in a T4SS-dependent manner. Expression of Smlt3024 in the periplasm of E. coli or its contact-dependent delivery via T4SS into E. coli by X. citri resulted in reduced growth rates, which could be counteracted by expression of its cognate inhibitor Smlt3025 in the target cell. Furthermore, expression of the VirD4 coupling protein of X. citri can restore the function of S. maltophilia ΔvirD4, demonstrating that effectors from one species can be recognized for transfer by T4SSs from another species. Interestingly, Smlt3024 is homologous to the N-terminal domain of large Ca2+-binding RTX proteins and the crystal structure of Smlt3025 revealed a topology similar to the iron-regulated protein FrpD from Neisseria meningitidis which has been shown to interact with the RTX protein FrpC. This work expands our current knowledge about the function of bacteria-killing T4SSs and increases the panel of effectors known to be involved in T4SS-mediated interbacterial competition, which possibly contribute to the establishment of S. maltophilia in clinical and environmental settings.
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Affiliation(s)
- Ethel Bayer-Santos
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo, Brazil
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - William Cenens
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Bruno Yasui Matsuyama
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Gabriel Umaji Oka
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Giancarlo Di Sessa
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Izabel Del Valle Mininel
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Tiago Lubiana Alves
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Chuck Shaker Farah
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo, Brazil
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5
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Tommassen J, Arenas J. Biological Functions of the Secretome of Neisseria meningitidis. Front Cell Infect Microbiol 2017; 7:256. [PMID: 28670572 PMCID: PMC5472700 DOI: 10.3389/fcimb.2017.00256] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 05/29/2017] [Indexed: 11/13/2022] Open
Abstract
Neisseria meningitidis is a Gram-negative bacterial pathogen that normally resides as a commensal in the human nasopharynx but occasionally causes disease with high mortality and morbidity. To interact with its environment, it transports many proteins across the outer membrane to the bacterial cell surface and into the extracellular medium for which it deploys the common and well-characterized autotransporter, two-partner and type I secretion mechanisms, as well as a recently discovered pathway for the surface exposure of lipoproteins. The surface-exposed and secreted proteins serve roles in host-pathogen interactions, including adhesion to host cells and extracellular matrix proteins, evasion of nutritional immunity imposed by iron-binding proteins of the host, prevention of complement activation, neutralization of antimicrobial peptides, degradation of immunoglobulins, and permeabilization of epithelial layers. Furthermore, they have roles in interbacterial interactions, including the formation and dispersal of biofilms and the suppression of the growth of bacteria competing for the same niche. Here, we will review the protein secretion systems of N. meningitidis and focus on the functions of the secreted proteins.
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Affiliation(s)
- Jan Tommassen
- Department of Molecular Microbiology and Institute of Biomembranes, Utrecht UniversityUtrecht, Netherlands
| | - Jesús Arenas
- Department of Molecular Microbiology and Institute of Biomembranes, Utrecht UniversityUtrecht, Netherlands
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6
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Sviridova E, Rezacova P, Bondar A, Veverka V, Novak P, Schenk G, Svergun DI, Kuta Smatanova I, Bumba L. Structural basis of the interaction between the putative adhesion-involved and iron-regulated FrpD and FrpC proteins of Neisseria meningitidis. Sci Rep 2017; 7:40408. [PMID: 28084396 PMCID: PMC5233953 DOI: 10.1038/srep40408] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 12/06/2016] [Indexed: 01/14/2023] Open
Abstract
The iron-regulated protein FrpD from Neisseria meningitidis is an outer membrane lipoprotein that interacts with very high affinity (Kd ~ 0.2 nM) with the N-terminal domain of FrpC, a Type I-secreted protein from the Repeat in ToXin (RTX) protein family. In the presence of Ca2+, FrpC undergoes Ca2+ -dependent protein trans-splicing that includes an autocatalytic cleavage of the Asp414-Pro415 peptide bond and formation of an Asp414-Lys isopeptide bond. Here, we report the high-resolution structure of FrpD and describe the structure-function relationships underlying the interaction between FrpD and FrpC1-414. We identified FrpD residues involved in FrpC1-414 binding, which enabled localization of FrpD within the low-resolution SAXS model of the FrpD-FrpC1-414 complex. Moreover, the trans-splicing activity of FrpC resulted in covalent linkage of the FrpC1-414 fragment to plasma membrane proteins of epithelial cells in vitro, suggesting that formation of the FrpD-FrpC1-414 complex may be involved in the interaction of meningococci with the host cell surface.
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Affiliation(s)
- Ekaterina Sviridova
- Faculty of Science, University of South Bohemia Ceske Budejovice, Branisovska 1760, 37005 Ceske Budejovice, Czech Republic.,Center for Nanobiology and Structural Biology, Institute of Microbiology, Czech Academy of Sciences, Zamek 136, 37333 Nove Hrady, Czech Republic
| | - Pavlina Rezacova
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16610 Prague, Czech Republic
| | - Alexey Bondar
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Czech Academy of Sciences, Zamek 136, 37333 Nove Hrady, Czech Republic.,Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16610 Prague, Czech Republic
| | - Vaclav Veverka
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16610 Prague, Czech Republic
| | - Petr Novak
- Institute of Microbiology, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic
| | - Gundolf Schenk
- EMBL Hamburg Outstation, c/o DESY, Notkestrasse 85, D-22603 Hamburg, Germany
| | - Dmitri I Svergun
- EMBL Hamburg Outstation, c/o DESY, Notkestrasse 85, D-22603 Hamburg, Germany
| | - Ivana Kuta Smatanova
- Faculty of Science, University of South Bohemia Ceske Budejovice, Branisovska 1760, 37005 Ceske Budejovice, Czech Republic.,Center for Nanobiology and Structural Biology, Institute of Microbiology, Czech Academy of Sciences, Zamek 136, 37333 Nove Hrady, Czech Republic
| | - Ladislav Bumba
- Institute of Microbiology, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic
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7
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Jirku M, Lansky Z, Bednarova L, Sulc M, Monincova L, Majer P, Vyklicky L, Vondrasek J, Teisinger J, Bousova K. The characterization of a novel S100A1 binding site in the N-terminus of TRPM1. Int J Biochem Cell Biol 2016; 78:186-193. [PMID: 27435061 DOI: 10.1016/j.biocel.2016.07.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 07/11/2016] [Accepted: 07/14/2016] [Indexed: 10/21/2022]
Abstract
Transient receptor potential melastatin-1 channel (TRPM1) is an important mediator of calcium influx into the cell that is expressed in melanoma and ON-bipolar cells. Similar to other members of the TRP channel family, the intracellular N- and C- terminal domains of TRPM1 are expected to play important roles in the modulation of TRPM1 receptor function. Among the most commonly occurring modulators of TRP channels are the cytoplasmically expressed calcium binding proteins calmodulin and S100 calcium-binding protein A1 (S100A1), but the interaction of TRPM1 with S100A1 has not been described yet. Here, using a combination of biophysical and bioinformatics methods, we have determined that the N-terminal L242-E344 region of TRPM1 is a S100A1 binding domain. We show that formation of the TRPM1/S100A1 complex is calcium-dependent. Moreover, our structural model of the complex explained data obtained from fluorescence spectroscopy measurements revealing that the complex formation is facilitated through interactions of clusters positively charged (K271A, R273A, R274A) and hydrophobic (L263A, V270A, L276A) residues at the N-terminus of TRPM1. Taken together, our data suggest a molecular mechanism for the potential regulation of TRPM1 by S100A1.
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Affiliation(s)
- Michaela Jirku
- Institute of Physiology, Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Zdenek Lansky
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, 25250 Vestec, Czech Republic
| | - Lucie Bednarova
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague, Czech Republic
| | - Miroslav Sulc
- Institute of Microbiology, Czech Academy of Sciences, 14220 Prague, Czech Republic; Faculty of Science, Charles University in Prague, 12843 Prague, Czech Republic
| | - Lenka Monincova
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague, Czech Republic
| | - Pavel Majer
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague, Czech Republic
| | - Ladislav Vyklicky
- Institute of Physiology, Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Jiri Vondrasek
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague, Czech Republic
| | - Jan Teisinger
- Institute of Physiology, Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Kristyna Bousova
- Institute of Physiology, Czech Academy of Sciences, 14220 Prague, Czech Republic; Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague, Czech Republic.
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8
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Characterization of the part of N-terminal PIP2 binding site of the TRPM1 channel. Biophys Chem 2015; 207:135-42. [DOI: 10.1016/j.bpc.2015.10.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 10/23/2015] [Accepted: 10/25/2015] [Indexed: 11/19/2022]
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9
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Kubáň V, Nováček J, Bumba L, Žídek L. NMR assignment of intrinsically disordered self-processing module of the FrpC protein of Neisseria meningitidis. BIOMOLECULAR NMR ASSIGNMENTS 2015; 9:435-440. [PMID: 26138689 DOI: 10.1007/s12104-015-9625-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 06/26/2015] [Indexed: 06/04/2023]
Abstract
The self-processing module (SPM) is an internal segment of the FrpC protein (P415-F591) secreted by the pathogenic Gram-negative bacterium Neisseria meningitidis during meningococcal infection of human upper respiratory tract. SPM mediates 'protein trans-splicing', a unique natural mechanism for editing of proteins, which involves a calcium-dependent autocatalytic cleavage of the peptide bond between D414 and P415 and covalent linkage of the cleaved fragment through its carboxy-terminal group of D414 to [Formula: see text]-amino group of lysine residue within a neighboring polypeptide chain. We present an NMR resonance assignment of the calcium-free SPM, which displays characteristic features of intrinsically disordered proteins. Non-uniformly sampled 5D HN(CA)CONH, 4D HCBCACON, and HCBCANCO spectra were recorded to resolve poorly dispersed resonance frequencies of the disordered protein and 91 % of SPM residues were unambiguously assigned. Analysis of the chemical shifts revealed that two regions of the intrinsically disordered SPM (A95-S101 and R120-I127) have a tendency to form a helical structure, whereas the residues P1-D7 and G36-A40 have the propensity to adopt a [Formula: see text]-structure.
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Affiliation(s)
- Vojtěch Kubáň
- CEITEC, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
| | - Jiří Nováček
- CEITEC, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
| | - Ladislav Bumba
- Institute of Microbiology of the ASCR, v. v. i, Vídeňská 1083, 14220, Prague 4, Czech Republic
| | - Lukáš Žídek
- CEITEC, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic.
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10
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Bousova K, Jirku M, Bumba L, Bednarova L, Sulc M, Franek M, Vyklicky L, Vondrasek J, Teisinger J. PIP2 and PIP3 interact with N-terminus region of TRPM4 channel. Biophys Chem 2015; 205:24-32. [PMID: 26071843 DOI: 10.1016/j.bpc.2015.06.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 06/04/2015] [Accepted: 06/06/2015] [Indexed: 01/07/2023]
Abstract
The transient receptor potential melastatin 4 (TRPM4) is a calcium-activated non-selective ion channel broadly expressed in a variety of tissues. Receptor has been identified as a crucial modulator of numerous calcium dependent mechanisms in the cell such as immune response, cardiac conduction, neurotransmission and insulin secretion. It is known that phosphoinositide lipids (PIPs) play a unique role in the regulation of TRP channel function. However the molecular mechanism of this process is still unknown. We characterized the binding site of PIP2 and its structural analogue PIP3 in the E733-W772 proximal region of the TRPM4 N-terminus via biophysical and molecular modeling methods. The specific positions R755 and R767 in this domain were identified as being important for interactions with PIP2/PIP3 ligands. Their mutations caused a partial loss of PIP2/PIP3 binding specificity. The interaction of PIP3 with TRPM4 channels has never been described before. These findings provide new insight into the ligand binding domains of the TRPM4 channel.
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Affiliation(s)
- Kristyna Bousova
- 2nd Faculty of Medicine, Charles University in Prague, 15006 Prague, Czech Republic; Institute of Physiology, Academy of Sciences of the Czech Republic, 14220 Prague, Czech Republic
| | - Michaela Jirku
- Institute of Physiology, Academy of Sciences of the Czech Republic, 14220 Prague, Czech Republic; Faculty of Science, Charles University in Prague, 12843 Prague, Czech Republic
| | - Ladislav Bumba
- Institute of Microbiology, Academy of Sciences of the Czech Republic, 14220 Prague, Czech Republic
| | - Lucie Bednarova
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 16610 Prague, Czech Republic
| | - Miroslav Sulc
- Institute of Microbiology, Academy of Sciences of the Czech Republic, 14220 Prague, Czech Republic
| | - Miloslav Franek
- 3rd Faculty of Medicine, Charles University in Prague, 10000 Prague, Czech Republic
| | - Ladislav Vyklicky
- Institute of Physiology, Academy of Sciences of the Czech Republic, 14220 Prague, Czech Republic
| | - Jiri Vondrasek
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 16610 Prague, Czech Republic
| | - Jan Teisinger
- Institute of Physiology, Academy of Sciences of the Czech Republic, 14220 Prague, Czech Republic.
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11
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O'Donovan D, Corcoran GD, Lucey B, Sleator RD. Campylobacter ureolyticus: a portrait of the pathogen. Virulence 2014; 5:498-506. [PMID: 24717836 PMCID: PMC4063811 DOI: 10.4161/viru.28776] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 04/03/2014] [Accepted: 04/03/2014] [Indexed: 01/29/2023] Open
Abstract
Herein, we provide a brief overview of the emerging bacterial pathogen Campylobacter ureolyticus. We describe the identification of the pathogen by molecular as opposed to classical culture based diagnostics and discuss candidate reservoirs of infection. We also review the available genomic data, outlining some of the major virulence factors, and discuss how these mechanisms likely contribute to pathogenesis of the organism.
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Affiliation(s)
- Dylan O'Donovan
- Department of Biological Sciences; Cork Institute of Technology; Bishopstown, Cork, Ireland
| | - Gerard D Corcoran
- Department of Diagnostic Microbiology; Cork University Hospital; Wilton, Cork, Ireland
| | - Brigid Lucey
- Department of Biological Sciences; Cork Institute of Technology; Bishopstown, Cork, Ireland
| | - Roy D Sleator
- Department of Biological Sciences; Cork Institute of Technology; Bishopstown, Cork, Ireland
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12
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Bumba L, Sviridova E, Kutá Smatanová I, Řezáčová P, Veverka V. Backbone resonance assignments of the outer membrane lipoprotein FrpD from Neisseria meningitidis. BIOMOLECULAR NMR ASSIGNMENTS 2014; 8:53-55. [PMID: 23225222 DOI: 10.1007/s12104-012-9451-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 12/04/2012] [Indexed: 06/01/2023]
Abstract
The iron-regulated FrpD protein is a unique lipoprotein embedded into the outer membrane of the Gram-negative bacterium Neisseria meningitidis. The biological function of FrpD remains unknown but might consist in anchoring to the bacterial cell surface the Type I-secreted FrpC protein, which belongs to a Repeat in ToXins (RTX) protein family and binds FrpD with very high affinity (K(d) = 0.2 nM). Here, we report the backbone (1)H, (13)C, and (15)N chemical shift assignments for the FrpD(43-271) protein that allow us to characterize the intimate interaction between FrpD and the N-terminal domain of FrpC.
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Affiliation(s)
- Ladislav Bumba
- Institute of Microbiology of the ASCR, v.v.i., Videnska 1083, Prague, 142 20, Czech Republic
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13
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Bullman S, Lucid A, Corcoran D, Sleator RD, Lucey B. Genomic investigation into strain heterogeneity and pathogenic potential of the emerging gastrointestinal pathogen Campylobacter ureolyticus. PLoS One 2013; 8:e71515. [PMID: 24023611 PMCID: PMC3758288 DOI: 10.1371/journal.pone.0071515] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 07/01/2013] [Indexed: 12/29/2022] Open
Abstract
The recent detection and isolation of C. ureolyticus from patients with diarrhoeal illness and inflammatory bowel diseases warrants further investigation into its role as an emerging pathogen of the human gastrointestinal tract. Regarding the pathogenic mechanisms employed by this species we provide the first whole genome analysis of two C. ureolyticus isolates including the type strain. Comparative analysis, subtractive hybridisation and gene ontology searches against other Campylobacter species identifies the high degree of heterogenicity between C. ureolyticus isolates, in addition to the identification of 106 putative virulence associated factors, 52 of which are predicted to be secreted. Such factors encompass each of the known virulence tactics of pathogenic Campylobacter spp. including adhesion and colonisation (CadF, PEB1, IcmF and FlpA), invasion (ciaB and 16 virB-virD4 genes) and toxin production (S-layer RTX and ZOT). Herein, we provide the first virulence catalogue for C. ureolyticus, the components of which theoretically provide this emerging species with sufficient arsenal to establish pathology.
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Affiliation(s)
- Susan Bullman
- Department of Biological Sciences, Cork Institute of Technology, Cork, Ireland
| | - Alan Lucid
- Department of Biological Sciences, Cork Institute of Technology, Cork, Ireland
| | - Daniel Corcoran
- Department of Medical Microbiology, Cork University Hospital, Cork, Ireland
| | - Roy D. Sleator
- Department of Biological Sciences, Cork Institute of Technology, Cork, Ireland
- * E-mail:
| | - Brigid Lucey
- Department of Biological Sciences, Cork Institute of Technology, Cork, Ireland
- Department of Medical Microbiology, Cork University Hospital, Cork, Ireland
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14
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Zigo M, Jonáková V, Šulc M, Maňásková-Postlerová P. Characterization of sperm surface protein patterns of ejaculated and capacitated boar sperm, with the detection of ZP binding candidates. Int J Biol Macromol 2013; 61:322-8. [PMID: 23916641 DOI: 10.1016/j.ijbiomac.2013.07.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 07/26/2013] [Accepted: 07/27/2013] [Indexed: 10/26/2022]
Abstract
Complementary molecules on the surface of both gametes are responsible for the interaction of sperm protein receptors with zona pellucida (ZP) saccharide structures, and many primary sperm receptors for ZP glycoproteins have been disclosed in various mammals. For our study, proteins were obtained from the surface of ejaculated and in vitro capacitated boar sperm. The isolated proteins were characterized by 1D- and 2D-electrophoretic protein profiles, and by glycoprotein staining. Our results show quantitative and qualitative differences in protein and glycoprotein patterns between ejaculated and capacitated sperm. Far-western blotting with ZP glycoproteins identified 17 interactions in the subproteome of the ejaculated sperm and 14 interactions in the subproteome of the capacitated sperm. High-molecular-mass proteins, coincident with binding to ZP, were sequence-identified. Angiotensin-converting enzyme (ACE), polycystic kidney disease receptor and egg jelly receptor (PKDREJ), and acrosin precursor were successfully identified. This is the first time PKDREJ has been identified on the surface of boar spermatozoa.
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Affiliation(s)
- Michal Zigo
- Laboratory of Reproductive Biology, Institute of Biotechnology, The Academy of Sciences of the Czech Republic, v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic; Department of Biochemistry, Faculty of Science, Charles University, Hlavova 8, 128 43, Prague 2, Czech Republic.
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15
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Rezabkova L, Kacirova M, Sulc M, Herman P, Vecer J, Stepanek M, Obsilova V, Obsil T. Structural modulation of phosducin by phosphorylation and 14-3-3 protein binding. Biophys J 2013. [PMID: 23199924 DOI: 10.1016/j.bpj.2012.09.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Phosducin (Pdc), a highly conserved phosphoprotein, plays an important role in the regulation of G protein signaling, transcriptional control, and modulation of blood pressure. Pdc is negatively regulated by phosphorylation followed by binding to the 14-3-3 protein, whose role is still unclear. To gain insight into the role of 14-3-3 in the regulation of Pdc function, we studied structural changes of Pdc induced by phosphorylation and 14-3-3 protein binding using time-resolved fluorescence spectroscopy. Our data show that the phosphorylation of the N-terminal domain of Pdc at Ser-54 and Ser-73 affects the structure of the whole Pdc molecule. Complex formation with 14-3-3 reduces the flexibility of both the N- and C-terminal domains of phosphorylated Pdc, as determined by time-resolved tryptophan and dansyl fluorescence. Therefore, our data suggest that phosphorylated Pdc undergoes a conformational change when binding to 14-3-3. These changes involve the G(t)βγ binding surface within the N-terminal domain of Pdc, and thus could explain the inhibitory effect of 14-3-3 on Pdc function.
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Affiliation(s)
- Lenka Rezabkova
- Department of Physical and Macromolecular Chemistry, Charles University in Prague, Prague, Czech Republic
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16
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Bily J, Grycova L, Holendova B, Jirku M, Janouskova H, Bousova K, Teisinger J. Characterization of the S100A1 protein binding site on TRPC6 C-terminus. PLoS One 2013; 8:e62677. [PMID: 23671622 PMCID: PMC3643951 DOI: 10.1371/journal.pone.0062677] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 03/24/2013] [Indexed: 12/24/2022] Open
Abstract
The transient receptor potential (TRP) protein superfamily consists of seven major groups, among them the "canonical TRP" family. The TRPC proteins are calcium-permeable nonselective cation channels activated after the emptying of intracellular calcium stores and appear to be gated by various types of messengers. The TRPC6 channel has been shown to be expressed in various tissues and cells, where it modulates the calcium level in response to external signals. Calcium binding proteins such as Calmodulin or the family of S100A proteins are regulators of TRPC channels. Here we characterized the overlapping integrative binding site for S100A1 at the C-tail of TRPC6, which is also able to accomodate various ligands such as Calmodulin and phosphatidyl-inositol-(4,5)-bisphosphate. Several positively charged amino acid residues (Arg852, Lys856, Lys859, Arg860 and Arg864) were determined by fluorescence anisotropy measurements for their participation in the calcium-dependent binding of S100A1 to the C terminus of TRPC6. The triple mutation Arg852/Lys859/Arg860 exhibited significant disruption of the binding of S100A1 to TRPC6. This indicates a unique involvement of these three basic residues in the integrative overlapping binding site for S100A1 on the C tail of TRPC6.
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Affiliation(s)
- Jan Bily
- Department of Protein Structures, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Lenka Grycova
- Department of Protein Structures, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Blanka Holendova
- Department of Protein Structures, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Michaela Jirku
- Department of Protein Structures, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Hana Janouskova
- Department of Protein Structures, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Kristyna Bousova
- Department of Protein Structures, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Jan Teisinger
- Department of Protein Structures, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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17
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Holakovska B, Grycova L, Jirku M, Sulc M, Bumba L, Teisinger J. Calmodulin and S100A1 protein interact with N terminus of TRPM3 channel. J Biol Chem 2012; 287:16645-55. [PMID: 22451665 DOI: 10.1074/jbc.m112.350686] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transient receptor potential melastatin 3 ion channel (TRPM3) belongs to the TRP family of cation-permeable ion channels involved in many important biological functions such as pain transduction, thermosensation, and mechanoregulation. The channel was reported to play an important role in Ca(2+) homeostasis, but its gating mechanisms, functions, and regulation are still under research. Utilizing biophysical and biochemical methods, we characterized two independent domains, Ala-35-Lys-124 and His-291-Gly-382, on the TRPM3 N terminus, responsible for interactions with the Ca(2+)-binding proteins calmodulin (CaM) and S100A1. We identified several positively charged residues within these domains as having a crucial impact on CaM/S100A1 binding. The data also suggest that the interaction is calcium-dependent. We also performed competition assays, which suggested that CaM and S100A1 are able to compete for the same binding sites within the TRPM3 N terminus. This is the first time that such an interaction has been shown for TRP family members.
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Affiliation(s)
- Blanka Holakovska
- Institute of Physiology, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague, Czech Republic
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18
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Linhartová I, Bumba L, Mašín J, Basler M, Osička R, Kamanová J, Procházková K, Adkins I, Hejnová-Holubová J, Sadílková L, Morová J, Sebo P. RTX proteins: a highly diverse family secreted by a common mechanism. FEMS Microbiol Rev 2011; 34:1076-112. [PMID: 20528947 PMCID: PMC3034196 DOI: 10.1111/j.1574-6976.2010.00231.x] [Citation(s) in RCA: 360] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Repeats-in-toxin (RTX) exoproteins of Gram-negative bacteria form a steadily growing family of proteins with diverse biological functions. Their common feature is the unique mode of export across the bacterial envelope via the type I secretion system and the characteristic, typically nonapeptide, glycine- and aspartate-rich repeats binding Ca2+ ions. In this review, we summarize the current state of knowledge on the organization of rtx loci and on the biological and biochemical activities of therein encoded proteins. Applying several types of bioinformatic screens on the steadily growing set of sequenced bacterial genomes, over 1000 RTX family members were detected, with the biological functions of most of them remaining to be characterized. Activities of the so far characterized RTX family members are then discussed and classified according to functional categories, ranging from the historically first characterized pore-forming RTX leukotoxins, through the large multifunctional enzymatic toxins, bacteriocins, nodulation proteins, surface layer proteins, up to secreted hydrolytic enzymes exhibiting metalloprotease or lipase activities of industrial interest.
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Affiliation(s)
- Irena Linhartová
- Institute of Microbiology AS CR v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic
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19
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General and molecular microbiology and microbial genetics in the IM CAS. J Ind Microbiol Biotechnol 2010; 37:1227-39. [DOI: 10.1007/s10295-010-0859-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 08/20/2010] [Indexed: 11/28/2022]
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20
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Sviridova E, Bumba L, Rezacova P, Prochazkova K, Kavan D, Bezouska K, Kuty M, Sebo P, Kuta Smatanova I. Crystallization and preliminary crystallographic characterization of the iron-regulated outer membrane lipoprotein FrpD from Neisseria meningitidis. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:1119-23. [PMID: 20823542 DOI: 10.1107/s174430911003215x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Accepted: 08/10/2010] [Indexed: 11/10/2022]
Abstract
Fe-regulated protein D (FrpD) is a Neisseria meningitidis outer membrane lipoprotein that may be involved in the anchoring of the secreted repeat in toxins (RTX) protein FrpC to the outer bacterial membrane. However, the function and biological roles of the FrpD and FrpC proteins remain unknown. Native and selenomethionine-substituted variants of recombinant FrpD43-271 protein were crystallized using the sitting-drop vapour-diffusion method. Diffraction data were collected to a resolution of 2.25 A for native FrpD43-271 protein and to a resolution of 2.00 A for selenomethionine-substituted FrpD43-271 (SeMet FrpD43-271) protein. The crystals of native FrpD43-271 protein belonged to the hexagonal space group P6(2) or P6(4), while the crystals of SeMet FrpD43-271 protein belonged to the primitive orthorhombic space group P2(1)2(1)2(1).
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Affiliation(s)
- Ekaterina Sviridova
- Institute of Physical Biology, University of South Bohemia Ceske Budejovice, Zamek 136, 373 33 Nove Hrady, Czech Republic
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21
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Pajon R, Yero D, Niebla O, Climent Y, Sardiñas G, García D, Perera Y, Llanes A, Delgado M, Cobas K, Caballero E, Taylor S, Brookes C, Gorringe A. Identification of new meningococcal serogroup B surface antigens through a systematic analysis of neisserial genomes. Vaccine 2009; 28:532-41. [PMID: 19837092 DOI: 10.1016/j.vaccine.2009.09.128] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Revised: 09/22/2009] [Accepted: 09/29/2009] [Indexed: 12/13/2022]
Abstract
The difficulty of inducing an effective immune response against the Neisseria meningitidis serogroup B capsular polysaccharide has lead to the search for vaccines for this serogroup based on outer membrane proteins. The availability of the first meningococcal genome (MC58 strain) allowed the expansion of high-throughput methods to explore the protein profile displayed by N. meningitidis. By combining a pan-genome analysis with an extensive experimental validation to identify new potential vaccine candidates, genes coding for antigens likely to be exposed on the surface of the meningococcus were selected after a multistep comparative analysis of entire Neisseria genomes. Eleven novel putative ORF annotations were reported for serogroup B strain MC58. Furthermore, a total of 20 new predicted potential pan-neisserial vaccine candidates were produced as recombinant proteins and evaluated using immunological assays. Potential vaccine candidate coding genes were PCR-amplified from a panel of representative strains and their variability analyzed using maximum likelihood approaches for detecting positive selection. Finally, five proteins all capable of inducing a functional antibody response vs N. meningitidis strain CU385 were identified as new attractive vaccine candidates: NMB0606 a potential YajC orthologue, NMB0928 the neisserial NlpB (BamC), NMB0873 a LolB orthologue, NMB1163 a protein belonging to a curli-like assembly machinery, and NMB0938 (a neisserial specific antigen) with evidence of positive selection appreciated for NMB0928. The new set of vaccine candidates and the novel proposed functions will open a new wave of research in the search for the elusive neisserial vaccine.
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Affiliation(s)
- Rolando Pajon
- Meningococcal Research Department, Division of Vaccines, Center for Genetic Engineering and Biotechnology, Ave 31, Cubanacan, Habana 10600, Cuba.
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22
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van Ulsen P, Kuhn K, Prinz T, Legner H, Schmid P, Baumann C, Tommassen J. Identification of proteins of
Neisseria meningitidis
induced under iron-limiting conditions using the isobaric tandem mass tag (TMT) labeling approach. Proteomics 2009; 9:1771-81. [DOI: 10.1002/pmic.200800642] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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23
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Lipoprotein NMB0928 from Neisseria meningitidis serogroup B as a novel vaccine candidate. Vaccine 2007; 25:8420-31. [DOI: 10.1016/j.vaccine.2007.09.053] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 09/20/2007] [Accepted: 09/23/2007] [Indexed: 11/15/2022]
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24
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Elias J, Vogel U. IS1301 fingerprint analysis of Neisseria meningitidis strains belonging to the ET-15 clone. J Clin Microbiol 2006; 45:159-67. [PMID: 17093016 PMCID: PMC1828961 DOI: 10.1128/jcm.01322-06] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Meningococci of the ET-15 clone frequently cause clusters of invasive meningococcal disease (IMD) and are associated with a high case-fatality ratio. Timely typing of strains from outbreaks of IMD caused by this clone is hampered by the low variability of its surface antigens. We present a new Southern blot-based typing method for ET-15 meningococci based on the insertion element IS1301, which was present in all 70 ET-15 strains tested. Fingerprints were stable in vitro over a period of 100 days of cultivation on agar plates. The discriminatory power of IS1301 fingerprinting exceeded that of typing by serogrouping and antigen sequencing of the outer membrane proteins PorA and FetA, as determined by the analysis of 52 epidemiologically unrelated strains. In addition, the method provided conclusive results with regard to the comparison of strains from clusters of IMD. The investigation of insertion sites of IS1301 revealed several new intragenic insertions, among others, into open reading frames homologous to mafB and tspB. A previously described insertion in nadA was present in more than two-thirds of the strains analyzed, suggesting that NadA is probably an unreliable vaccine candidate for the prevention of ET-15 disease.
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Affiliation(s)
- Johannes Elias
- Institute for Hygiene and Microbiology, University of Würzburg, 97080 Würzburg, Germany.
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25
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Parker D, Kennan RM, Myers GS, Paulsen IT, Songer JG, Rood JI. Regulation of type IV fimbrial biogenesis in Dichelobacter nodosus. J Bacteriol 2006; 188:4801-11. [PMID: 16788189 PMCID: PMC1483018 DOI: 10.1128/jb.00255-06] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Type IV fimbriae are expressed by several bacterial pathogens and are essential for virulence in Dichelobacter nodosus, which causes ovine footrot. We have identified a two-component signal transduction system (PilR/S) and an alternative sigma factor (sigma 54) that were shown by insertional inactivation to be required for the regulation of fimbrial biogenesis in D. nodosus. Western blots showed that in both pilR and rpoN mutants, fimbrial subunit production was significantly reduced by a process that was shown to occur at a PilR- and sigma 54-dependent promoter. The mutants lacked surface fimbriae, which were shown to be required for the adherence of D. nodosus cells to tissue culture monolayers. The reduction in fimbrial subunit production in these mutants also resulted in a concomitant loss of the ability to secrete extracellular proteases. A maltose binding protein-PilR fusion protein was purified and was shown to bind specifically to a region located 234 to 594 bp upstream of the fimA transcriptional start point. To determine additional targets of PilR and sigma 54, genome-wide transcriptional profiling was performed using a whole-genome oligonucleotide microarray. The results indicated that PilR and sigma 54 regulated genes other than fimA; these genes appear to encode surface-exposed proteins whose role in virulence is unknown. In conclusion, this study represents a significant advancement in our understanding of how the ability of D. nodosus to cause ovine footrot is regulated, as we have shown that the biogenesis of type IV fimbriae in D. nodosus is regulated by a sigma 54-dependent PilR/S system that also indirectly controls protease secretion.
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Affiliation(s)
- Dane Parker
- Australian Research Council Centre of Excellence for Structrral and Functional Microbial Genomics and Victorian Bioinformatics Consortium, Department of Microbiology, Monash University, Victoria 3800, Australia
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26
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van Ulsen P, Tommassen J. Protein secretion and secreted proteins in pathogenicNeisseriaceae. FEMS Microbiol Rev 2006; 30:292-319. [PMID: 16472308 DOI: 10.1111/j.1574-6976.2006.00013.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Secreted proteins of pathogenic bacteria are often essential virulence factors. They are involved, for example, in the adherence of the bacteria to host cells or required to suppress the host's defence mechanisms. Until recently, only IgA1 protease had been studied in detail in the NeisseriaceaeNeisseria meningitidis and Neisseria gonorrhoeae. The availability of their genome sequences, however, has boosted research in this area. Here, we present a survey of the secretome of the pathogenic Neisseriaceae, based on the available genome sequences, and the current knowledge of the functions and structures of the secreted proteins. Of the six protein-secretion pathways that are widely disseminated among Gram-negative bacteria, three pathways appear to be present among the Neisseriaceae, i.e. the autotransporter-, the two-partner- and the type I-secretion mechanisms. Comparison of the predicted secretomes reveals a considerable flexibility. As compared with N. meningitidis and the nonpathogen N. lactamica, N. gonorrhoeae appears to have a considerably degenerated secretome, which may reflect its altered niche occupancy. The flexibility of the secretome may be enhanced by the presence of ORFs in the genomes potentially encoding fragments of secreted proteins. We hypothesize that these ORFs may substitute for the corresponding fragments in the full-length genes through genetic recombination, thereby changing the host-cell receptor specificity of the secreted protein.
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Affiliation(s)
- Peter van Ulsen
- Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, Utrecht, The Netherlands
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27
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Wooldridge KG, Kizil M, Wells DB, Ala'aldeen DAA. Unusual genetic organization of a functional type I protein secretion system in Neisseria meningitidis. Infect Immun 2005; 73:5554-67. [PMID: 16113272 PMCID: PMC1231126 DOI: 10.1128/iai.73.9.5554-5567.2005] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Proteins secreted by Neisseria meningitidis are thought to play important roles in the pathogenesis of meningococcal disease. These proteins include the iron-repressible repeat-in-toxin (RTX) exoprotein FrpC. Related proteins in other pathogens are secreted via a type I secretion system (TOSS), but such a system has not been demonstrated in N. meningitidis. An in silico search of the group B meningococcal genome suggested the presence of a uniquely organized TOSS. Genes encoding homologs of the Escherichia coli HlyB (ATP-binding), HlyD (membrane fusion), and TolC (outer membrane channel) proteins were identified. In contrast to the cistronic organization of the secretion genes in most other rtx operons, the hlyD and tolC genes were adjacent but unlinked to hlyB; neither locus was part of an operon containing genes encoding putative TOSS substrates. Both loci were flanked by genes normally associated with mobile genetic elements. The three genes were shown to be expressed independently. Mutation at either locus resulted in an inability to secrete FrpC and a related protein, here called FrpC2. Successful complementation of these mutations at an ectopic site confirmed the observed phenotypes were caused by loss of function of the putative TOSS genes. We show that genes scattered in the meningococcal genome encode a functional TOSS required for secretion of the meningococcal RTX proteins.
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Affiliation(s)
- Karl G Wooldridge
- Division of Microbiology and Infectious Diseases, Queens Medical Centre, Nottingham NG7 2UH, United Kingdom.
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