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Abstract
Type III secretion systems (T3SSs) are utilized by Gram-negative pathogens to enhance their pathogenesis. This secretion system is associated with the delivery of effectors through a needle-like structure from the bacterial cytosol directly into a target eukaryotic cell. These effector proteins then manipulate specific eukaryotic cell functions to benefit pathogen survival within the host. The obligate intracellular pathogens of the family Chlamydiaceae have a highly evolutionarily conserved nonflagellar T3SS that is an absolute requirement for their survival and propagation within the host with about one-seventh of the genome dedicated to genes associated with the T3SS apparatus, chaperones, and effectors. Chlamydiae also have a unique biphasic developmental cycle where the organism alternates between an infectious elementary body (EB) and replicative reticulate body (RB). T3SS structures have been visualized on both EBs and RBs. And there are effector proteins that function at each stage of the chlamydial developmental cycle, including entry and egress. This review will discuss the history of the discovery of chlamydial T3SS and the biochemical characterization of components of the T3SS apparatus and associated chaperones in the absence of chlamydial genetic tools. These data will be contextualized into how the T3SS apparatus functions throughout the chlamydial developmental cycle and the utility of heterologous/surrogate models to study chlamydial T3SS. Finally, there will be a targeted discussion on the history of chlamydial effectors and recent advances in the field.
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Affiliation(s)
- Elizabeth A. Rucks
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Durham Research Center II, Omaha, Nebraska, USA
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2
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Case HB, Gonzalez S, Gustafson ME, Dickenson NE. Differential regulation of Shigella Spa47 ATPase activity by a native C-terminal product of Spa33. Front Cell Infect Microbiol 2023; 13:1183211. [PMID: 37389216 PMCID: PMC10302723 DOI: 10.3389/fcimb.2023.1183211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 05/17/2023] [Indexed: 07/01/2023] Open
Abstract
Shigella is a Gram-negative bacterial pathogen that relies on a single type three secretion system (T3SS) as its primary virulence factor. The T3SS includes a highly conserved needle-like apparatus that directly injects bacterial effector proteins into host cells, subverting host cell function, initiating infection, and circumventing resulting host immune responses. Recent findings have located the T3SS ATPase Spa47 to the base of the Shigella T3SS apparatus and have correlated its catalytic function to apparatus formation, protein effector secretion, and overall pathogen virulence. This critical correlation makes Spa47 ATPase activity regulation a likely point of native control over Shigella virulence and a high interest target for non-antibiotic- based therapeutics. Here, we provide a detailed characterization of the natural 11.6 kDa C-terminal translation product of the Shigella T3SS protein Spa33 (Spa33C), showing that it is required for proper virulence and that it pulls down with several known T3SS proteins, consistent with a structural role within the sorting platform of the T3SS apparatus. In vitro binding assays and detailed kinetic analyses suggest an additional role, however, as Spa33C differentially regulates Spa47 ATPase activity based on Spa47s oligomeric state, downregulating Spa47 monomer activity and upregulating activity of both homo-oligomeric Spa47 and the hetero-oligomeric MxiN2Spa47 complex. These findings identify Spa33C as only the second known differential T3SS ATPase regulator to date, with the Shigella protein MxiN representing the other. Describing this differential regulatory protein pair begins to close an important gap in understanding of how Shigella may modulate virulence through Spa47 activity and T3SS function.
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Affiliation(s)
| | | | | | - Nicholas E. Dickenson
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, United States
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3
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Martínez OF, Duque HM, Franco OL. Peptidomimetics as Potential Anti-Virulence Drugs Against Resistant Bacterial Pathogens. Front Microbiol 2022; 13:831037. [PMID: 35516442 PMCID: PMC9062693 DOI: 10.3389/fmicb.2022.831037] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 02/28/2022] [Indexed: 12/11/2022] Open
Abstract
The uncontrollable spread of superbugs calls for new approaches in dealing with microbial-antibiotic resistance. Accordingly, the anti-virulence approach has arisen as an attractive unconventional strategy to face multidrug-resistant pathogens. As an emergent strategy, there is an imperative demand for discovery, design, and development of anti-virulence drugs. In this regard, peptidomimetic compounds could be a valuable source of anti-virulence drugs, since these molecules circumvent several shortcomings of natural peptide-based drugs like proteolytic instability, immunogenicity, toxicity, and low bioavailability. Some emerging evidence points to the feasibility of peptidomimetics to impair pathogen virulence. Consequently, in this review, we shed some light on the potential of peptidomimetics as anti-virulence drugs to overcome antibiotic resistance. Specifically, we address the anti-virulence activity of peptidomimetics against pathogens' secretion systems, biofilms, and quorum-sensing systems.
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Affiliation(s)
- Osmel Fleitas Martínez
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Centro de Análises Proteômicas e Bioquímicas, Universidade Católica de Brasília, Brasília, Brazil.,Programa de Pós-Graduação em Biotecnologia, S-Inova Biotech, Universidade Católica Dom Bosco, Campo Grande, Brazil
| | - Harry Morales Duque
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Centro de Análises Proteômicas e Bioquímicas, Universidade Católica de Brasília, Brasília, Brazil
| | - Octávio Luiz Franco
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Centro de Análises Proteômicas e Bioquímicas, Universidade Católica de Brasília, Brasília, Brazil.,Programa de Pós-Graduação em Biotecnologia, S-Inova Biotech, Universidade Católica Dom Bosco, Campo Grande, Brazil
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4
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Ouellette SP, Blay EA, Hatch ND, Fisher-Marvin LA. CRISPR Interference To Inducibly Repress Gene Expression in Chlamydia trachomatis. Infect Immun 2021; 89:e0010821. [PMID: 33875479 PMCID: PMC8373233 DOI: 10.1128/iai.00108-21] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 04/08/2021] [Indexed: 12/16/2022] Open
Abstract
The ability to inducibly repress gene expression is critical to the study of organisms, like Chlamydia, with reduced genomes in which the majority of genes are likely to be essential. We recently described the feasibility of a CRISPR interference (CRISPRi) system to inducibly repress gene expression in Chlamydia trachomatis. However, the initial system suffered from some drawbacks, primarily leaky expression of the anhydrotetracycline (aTc)-inducible dCas9 ortholog and plasmid instability, which prevented population-wide studies (e.g., transcript analyses) of the effects of knockdown. Here, we describe various modifications to the original system that have allowed us to measure gene expression changes within a transformed population of C. trachomatis serovar L2. These modifications include (i) a change in the vector backbone, (ii) the introduction of a weaker ribosome binding site driving dCas9 translation, and (iii) the addition of a degradation tag to dCas9 itself. With these changes, we demonstrate the ability to inducibly repress a target gene sequence, as measured by the absence of protein by immunofluorescence analysis and by decreased transcript levels. Importantly, the expression of dCas9 alone (i.e., without a guide RNA [gRNA]) had minimal impact on chlamydial growth or development. We also describe complementation of the knockdown effect by introducing a transcriptional fusion of the target gene 3' to dCas9. Finally, we demonstrate the functionality of a second CRISPRi system based on a dCas12 system that expands the number of potential chromosomal targets. These tools should provide the ability to study essential gene function in Chlamydia.
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Affiliation(s)
- Scot P. Ouellette
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Emmanuel A. Blay
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Nathan D. Hatch
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Laura A. Fisher-Marvin
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
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5
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Hotinger JA, Pendergrass HA, May AE. Molecular Targets and Strategies for Inhibition of the Bacterial Type III Secretion System (T3SS); Inhibitors Directly Binding to T3SS Components. Biomolecules 2021; 11:biom11020316. [PMID: 33669653 PMCID: PMC7922566 DOI: 10.3390/biom11020316] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 01/01/2023] Open
Abstract
The type III secretion system (T3SS) is a virulence apparatus used by many Gram-negative pathogenic bacteria to cause infections. Pathogens utilizing a T3SS are responsible for millions of infections yearly. Since many T3SS knockout strains are incapable of causing systemic infection, the T3SS has emerged as an attractive anti-virulence target for therapeutic design. The T3SS is a multiprotein molecular syringe that enables pathogens to inject effector proteins into host cells. These effectors modify host cell mechanisms in a variety of ways beneficial to the pathogen. Due to the T3SS’s complex nature, there are numerous ways in which it can be targeted. This review will be focused on the direct targeting of components of the T3SS, including the needle, translocon, basal body, sorting platform, and effector proteins. Inhibitors will be considered a direct inhibitor if they have a binding partner that is a T3SS component, regardless of the inhibitory effect being structural or functional.
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Hotinger JA, May AE. Antibodies Inhibiting the Type III Secretion System of Gram-Negative Pathogenic Bacteria. Antibodies (Basel) 2020; 9:antib9030035. [PMID: 32726928 PMCID: PMC7551047 DOI: 10.3390/antib9030035] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/16/2020] [Accepted: 07/22/2020] [Indexed: 12/11/2022] Open
Abstract
Pathogenic bacteria are a global health threat, with over 2 million infections caused by Gram-negative bacteria every year in the United States. This problem is exacerbated by the increase in resistance to common antibiotics that are routinely used to treat these infections, creating an urgent need for innovative ways to treat and prevent virulence caused by these pathogens. Many Gram-negative pathogenic bacteria use a type III secretion system (T3SS) to inject toxins and other effector proteins directly into host cells. The T3SS has become a popular anti-virulence target because it is required for pathogenesis and knockouts have attenuated virulence. It is also not required for survival, which should result in less selective pressure for resistance formation against T3SS inhibitors. In this review, we will highlight selected examples of direct antibody immunizations and the use of antibodies in immunotherapy treatments that target the bacterial T3SS. These examples include antibodies targeting the T3SS of Pseudomonas aeruginosa, Yersinia pestis, Escherichia coli, Salmonella enterica, Shigella spp., and Chlamydia trachomatis.
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7
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Ahmad S, Kim CSK, Tarran R. The SPLUNC1-βENaC complex prevents Burkholderia cenocepacia invasion in normal airway epithelia. Respir Res 2020; 21:190. [PMID: 32680508 PMCID: PMC7368771 DOI: 10.1186/s12931-020-01454-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 07/13/2020] [Indexed: 12/13/2022] Open
Abstract
Cystic fibrosis (CF) patients are extremely vulnerable to Burkholderia cepacia complex (Bcc) infections. However, the underlying etiology is poorly understood. We tested the hypothesis that short palate lung and nasal epithelial clone 1 (SPLUNC1)–epithelial sodium channel (ENaC) interactions at the plasma membrane are required to reduce Bcc burden in normal airways. To determine if SPLUNC1 was needed to reduce Bcc burden in the airways, SPLUNC1 knockout mice and their wild-type littermates were infected with B. cenocepacia strain J2315. SPLUNC1 knockout mice had increased bacterial burden in the lungs compared to wild-type littermate mice. SPLUNC1-knockdown primary human bronchial epithelia (HBECs) were incubated with J2315, which resulted in increased bacterial burden compared to non-transduced HBECs. We next determined the interaction of the SPLUNC1-ENaC complex during J2315 infection. SPLUNC1 remained at the apical plasma membrane of normal HBECs but less was present at the apical plasma membrane of CF HBECs. Additionally, SPLUNC1-βENaC complexes reduced intracellular J2315 burden. Our data indicate that (i) secreted SPLUNC1 is required to reduce J2315 burden in the airways and (ii) its interaction with ENaC prevents cellular invasion of J2315.
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Affiliation(s)
- Saira Ahmad
- Department of Cell Biology and Physiology, The University of North Carolina, Marsico Lung Insitute, 115 Mason Farm Rd CB 7545, UNC, Chapel Hill, NC, 27599, USA
| | - Christine Seul Ki Kim
- Department of Cell Biology and Physiology, The University of North Carolina, Marsico Lung Insitute, 115 Mason Farm Rd CB 7545, UNC, Chapel Hill, NC, 27599, USA.,Present address: Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Robert Tarran
- Department of Cell Biology and Physiology, The University of North Carolina, Marsico Lung Insitute, 115 Mason Farm Rd CB 7545, UNC, Chapel Hill, NC, 27599, USA.
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8
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Case HB, Mattock DS, Miller BR, Dickenson NE. Novel Noncompetitive Type Three Secretion System ATPase Inhibitors Shut Down Shigella Effector Secretion. Biochemistry 2020; 59:2667-2678. [PMID: 32567308 DOI: 10.1021/acs.biochem.0c00431] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Shigella is the causative agent of bacillary dysentery and is responsible for an estimated 165 million infections and 600,000 deaths annually. Like many Gram-negative pathogens, Shigella relies on a type three secretion system (T3SS) to initiate and sustain infection by directly injecting effector proteins into host cells. Protein secretion through the needle-like injectisome and overall Shigella virulence rely on the T3SS ATPase Spa47, making it a likely means for T3SS regulation and an attractive target for therapeutic small molecule inhibitors. Here, we utilize a recently solved 2.15 Å crystal structure of Spa47 to computationally screen 7.6 million drug-like compounds for candidates which avoid the highly conserved active site by targeting a distal, but critical, interface between adjacent protomers of the Spa47 homohexamer. Ten of the top inhibitor candidates were characterized, identifying novel Spa47 inhibitors that reduce in vitro ATPase activity by as much as 87.9 ± 10.5% with IC50's as low as 25 ± 20 μM and reduce in vivo Shigella T3SS protein secretion by as much as 94.7 ± 3.0%. Kinetic analyses show that the inhibitors operate through a noncompetitive mechanism that likely supports the inhibitors' low cytotoxicity, as they avoid off-target ATPases involved in either Shigella or mammalian cell metabolism. Interestingly, the inhibitors display nearly identical inhibition profiles for Spa47 and the T3SS ATPases EscN from E. coli and FliI from Salmonella. Together, the results of this study provide much-needed insight into T3SS ATPase inhibition mechanisms and a strong platform for developing broadly effective cross-pathogen T3SS ATPase inhibitors.
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Affiliation(s)
- Heather B Case
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
| | - Dominic S Mattock
- Department of Chemistry, Truman State University, Kirksville, Missouri 63501, United States
| | - Bill R Miller
- Department of Chemistry, Truman State University, Kirksville, Missouri 63501, United States
| | - Nicholas E Dickenson
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
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9
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Zhou Y, Lu X, Huang D, Lu Y, Zhang H, Zhang L, Yu P, Wang F, Wang Y. A novel protease inhibitor causes inclusion vacuole reduction and disrupts the intracellular growth of Chlamydia trachomatis. Biochem Biophys Res Commun 2019; 516:157-162. [PMID: 31202460 DOI: 10.1016/j.bbrc.2019.05.184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 05/29/2019] [Accepted: 05/30/2019] [Indexed: 11/16/2022]
Abstract
Chlamydia (C.) trachomatis, characterized by a unique biphasic life cycle, is an obligate intracellular bacterial pathogen which is responsible for the highest number of sexually transmitted bacterial infections globally. However, its pathogenic mechanisms have not been fully elucidated because of its unique developmental cycle and obligate intracellular nature. High temperature requirement (HtrA), a critical protease and chaperone, has been previously demonstrated to be essential for several functions and the replicative phase in the C. trachomatis developmental cycle. In the current study, we designed and synthesized a novel peptidomimetic inhibitor targeting C. trachomatis HtrA (CtHtrA) using homology modeling and chemical synthesis. The inhibitor was tested in chlamydia in the mid-replicative phase and resulted in a significant loss of viable infectious progeny and diminishing inclusion size and number at a relatively low concentration. This finding not only indicates that CtHtrA plays a critical role during the replicative phase of the chlamydial developmental cycle but also reveals a useful target for the design of novel anti-chlamydial agents.
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Affiliation(s)
- Yachun Zhou
- Department of Immunology, School of Basic Medical Science, Central South University, Changsha, Hunan, China
| | - Xiaofang Lu
- Department of Immunology, School of Basic Medical Science, Central South University, Changsha, Hunan, China
| | - Dong Huang
- Department of Immunology, School of Basic Medical Science, Central South University, Changsha, Hunan, China
| | - Yuying Lu
- Department of Immunology, School of Basic Medical Science, Central South University, Changsha, Hunan, China
| | - Hongbo Zhang
- Department of Pathology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Lei Zhang
- Department of Urinary Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ping Yu
- Department of Immunology, School of Basic Medical Science, Central South University, Changsha, Hunan, China
| | - Fuyan Wang
- Department of Immunology, School of Basic Medical Science, Central South University, Changsha, Hunan, China.
| | - Yong Wang
- Department of Forensic Science, School of Basic Medical Science, Central South University, Changsha, Hunan, China.
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10
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Halder PK, Roy C, Datta S. Structural and functional characterization of type three secretion system ATPase PscN and its regulator PscL from Pseudomonas aeruginosa. Proteins 2018; 87:276-288. [PMID: 30561072 DOI: 10.1002/prot.25648] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 10/29/2018] [Accepted: 12/12/2018] [Indexed: 12/16/2022]
Affiliation(s)
- Pranab Kumar Halder
- Structural Biology and Bioinformatics Division; Council of Scientific and Industrial Research-Indian Institute of Chemical Biology; Kolkata West Bengal India
| | - Chittran Roy
- Structural Biology and Bioinformatics Division; Council of Scientific and Industrial Research-Indian Institute of Chemical Biology; Kolkata West Bengal India
| | - Saumen Datta
- Structural Biology and Bioinformatics Division; Council of Scientific and Industrial Research-Indian Institute of Chemical Biology; Kolkata West Bengal India
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11
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Heineke MH, van der Steen LPE, Korthouwer RM, Hage JJ, Langedijk JPM, Benschop JJ, Bakema JE, Slootstra JW, van Egmond M. Peptide mimetics of immunoglobulin A (IgA) and FcαRI block IgA-induced human neutrophil activation and migration. Eur J Immunol 2017; 47:1835-1845. [PMID: 28736835 PMCID: PMC5659136 DOI: 10.1002/eji.201646782] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 06/06/2017] [Accepted: 07/20/2017] [Indexed: 12/19/2022]
Abstract
The cross‐linking of the IgA Fc receptor (FcαRI) by IgA induces release of the chemoattractant LTB4, thereby recruiting neutrophils in a positive feedback loop. IgA autoantibodies of patients with autoimmune blistering skin diseases therefore induce massive recruitment of neutrophils, resulting in severe tissue damage. To interfere with neutrophil mobilization and reduce disease morbidity, we developed a panel of specific peptides mimicking either IgA or FcαRI sequences. CLIPS technology was used to stabilize three‐dimensional structures and to increase peptides’ half‐life. IgA and FcαRI peptides reduced phagocytosis of IgA‐coated beads, as well as IgA‐induced ROS production and neutrophil migration in in vitro and ex vivo (human skin) experiments. Since topical application would be the preferential route of administration, Cetomacrogol cream containing an IgA CLIPS peptide was developed. In the presence of a skin permeation enhancer, peptides in this cream were shown to penetrate the skin, while not diffusing systemically. Finally, epitope mapping was used to discover sequences important for binding between IgA and FcαRI. In conclusion, a cream containing IgA or FcαRI peptide mimetics, which block IgA‐induced neutrophil activation and migration in the skin may have therapeutic potential for patients with IgA‐mediated blistering skin diseases.
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Affiliation(s)
- Marieke H Heineke
- Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, The Netherlands
| | - Lydia P E van der Steen
- Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, The Netherlands
| | - Rianne M Korthouwer
- Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, The Netherlands
| | - J Joris Hage
- Department of Plastic and Reconstructive Surgery, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands
| | | | - Joris J Benschop
- Pepscan Therapeutics, Zuidersluisweg 2, Lelystad, The Netherlands
| | - Jantine E Bakema
- Department of Otolaryngology/Head-Neck Surgery, VU University Medical Center, Amsterdam, The Netherlands
| | | | - Marjolein van Egmond
- Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, The Netherlands.,Department of Surgery, VU University Medical Center, Amsterdam, The Netherlands
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12
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Gaytán MO, Martínez-Santos VI, Soto E, González-Pedrajo B. Type Three Secretion System in Attaching and Effacing Pathogens. Front Cell Infect Microbiol 2016; 6:129. [PMID: 27818950 PMCID: PMC5073101 DOI: 10.3389/fcimb.2016.00129] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 09/27/2016] [Indexed: 02/06/2023] Open
Abstract
Enteropathogenic Escherichia coli and enterohemorrhagic E. coli are diarrheagenic bacterial human pathogens that cause severe gastroenteritis. These enteric pathotypes, together with the mouse pathogen Citrobacter rodentium, belong to the family of attaching and effacing pathogens that form a distinctive histological lesion in the intestinal epithelium. The virulence of these bacteria depends on a type III secretion system (T3SS), which mediates the translocation of effector proteins from the bacterial cytosol into the infected cells. The core architecture of the T3SS consists of a multi-ring basal body embedded in the bacterial membranes, a periplasmic inner rod, a transmembrane export apparatus in the inner membrane, and cytosolic components including an ATPase complex and the C-ring. In addition, two distinct hollow appendages are assembled on the extracellular face of the basal body creating a channel for protein secretion: an approximately 23 nm needle, and a filament that extends up to 600 nm. This filamentous structure allows these pathogens to get through the host cells mucus barrier. Upon contact with the target cell, a translocation pore is assembled in the host membrane through which the effector proteins are injected. Assembly of the T3SS is strictly regulated to ensure proper timing of substrate secretion. The different type III substrates coexist in the bacterial cytoplasm, and their hierarchical secretion is determined by specialized chaperones in coordination with two molecular switches and the so-called sorting platform. In this review, we present recent advances in the understanding of the T3SS in attaching and effacing pathogens.
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Affiliation(s)
- Meztlli O Gaytán
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Ciudad de México, Mexico
| | - Verónica I Martínez-Santos
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Ciudad de México, Mexico
| | - Eduardo Soto
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Ciudad de México, Mexico
| | - Bertha González-Pedrajo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Ciudad de México, Mexico
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13
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Ferrell JC, Fields KA. A working model for the type III secretion mechanism in Chlamydia. Microbes Infect 2015; 18:84-92. [PMID: 26515030 DOI: 10.1016/j.micinf.2015.10.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 10/19/2015] [Accepted: 10/19/2015] [Indexed: 01/09/2023]
Abstract
It has been appreciated for almost 20 years that members of the Chlamydiales possess a virulence-associated type III secretion mechanism. Given the obligate intracellular nature of these bacteria, defining exactly how type III secretion functions to promote pathogenesis has been challenging. We present a working model herein that is based on current evidence.
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Affiliation(s)
- Joshua C Ferrell
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Kenneth A Fields
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY 40536, USA.
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14
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McShan AC, De Guzman RN. The bacterial type III secretion system as a target for developing new antibiotics. Chem Biol Drug Des 2015; 85:30-42. [PMID: 25521643 DOI: 10.1111/cbdd.12422] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 08/25/2014] [Accepted: 08/26/2014] [Indexed: 01/14/2023]
Abstract
Antibiotic resistance in pathogens requires new targets for developing novel antibacterials. The bacterial type III secretion system (T3SS) is an attractive target for developing antibacterials as it is essential in the pathogenesis of many Gram-negative bacteria. The T3SS consists of structural proteins, effectors, and chaperones. Over 20 different structural proteins assemble into a complex nanoinjector that punctures a hole on the eukaryotic cell membrane to allow the delivery of effectors directly into the host cell cytoplasm. Defects in the assembly and function of the T3SS render bacteria non-infective. Two major classes of small molecules, salicylidene acylhydrazides and thiazolidinones, have been shown to inhibit multiple genera of bacteria through the T3SS. Many additional chemically and structurally diverse classes of small molecule inhibitors of the T3SS have been identified as well. While specific targets within the T3SS of a few inhibitors have been suggested, the vast majority of specific protein targets within the T3SS remain to be identified or characterized. Other T3SS inhibitors include polymers, proteins, and polypeptides mimics. In addition, T3SS activity is regulated by its interaction with biologically relevant molecules, such as bile salts and sterols, which could serve as scaffolds for drug design.
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Affiliation(s)
- Andrew C McShan
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, 66045, USA
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15
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Barta ML, Battaile KP, Lovell S, Hefty PS. Hypothetical protein CT398 (CdsZ) interacts with σ(54) (RpoN)-holoenzyme and the type III secretion export apparatus in Chlamydia trachomatis. Protein Sci 2015; 24:1617-32. [PMID: 26173998 DOI: 10.1002/pro.2746] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 07/06/2015] [Indexed: 12/22/2022]
Abstract
A significant challenge to bacteriology is the relatively large proportion of proteins that lack sufficient sequence similarity to support functional annotation (i.e. hypothetical proteins). The aim of this study was to apply protein structural homology to gain insights into a candidate protein of unknown function (CT398) within the medically important, obligate intracellular bacterium Chlamydia trachomatis. C. trachomatis is a major human pathogen responsible for numerous infections throughout the world that can lead to blindness and infertility. A 2.12 Å crystal structure of hypothetical protein CT398 was determined that was comprised of N-terminal coiled-coil and C-terminal Zn-ribbon domains. The structure of CT398 displayed a high degree of structural similarity to FlgZ (Flagellar-associated zinc-ribbon domain protein) from Helicobacter pylori. This observation directed analyses of candidate protein partners of CT398, revealing interactions with two paralogous type III secretion system (T3SS) ATPase-regulators (CdsL and FliH) and the alternative sigma factor RpoN (σ(54) ). Furthermore, genetic introduction of a conditional expression, affinity-tagged construct into C. trachomatis enabled the purification of a CT398-RpoN-holoenzyme complex, suggesting a potential role for CT398 in modulating transcriptional activity during infection. The interactions reported here, in tandem with previous FlgZ studies in H. pylori, indicate that CT398 functions as a regulator of several key areas of chlamydial biology throughout the developmental cycle. Accordingly, we propose that CT398 be named CdsZ (Contact-dependent secretion-associated zinc-ribbon domain protein).
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Affiliation(s)
- Michael L Barta
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, 66045
| | - Kevin P Battaile
- IMCA-CAT, Hauptman-Woodward Medical Research Institute, Argonne, Illinois
| | - Scott Lovell
- Protein Structure Laboratory, Del Shankel Structural Biology Center, University of Kansas, Lawrence, KS, 66045
| | - P Scott Hefty
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, 66045
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16
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Allison SE, Tuinema BR, Everson ES, Sugiman-Marangos S, Zhang K, Junop MS, Coombes BK. Identification of the docking site between a type III secretion system ATPase and a chaperone for effector cargo. J Biol Chem 2014; 289:23734-44. [PMID: 25035427 DOI: 10.1074/jbc.m114.578476] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
A number of Gram-negative pathogens utilize type III secretion systems (T3SSs) to inject bacterial effector proteins into the host. An important component of T3SSs is a conserved ATPase that captures chaperone-effector complexes and energizes their dissociation to facilitate effector translocation. To date, there has been limited work characterizing the chaperone-T3SS ATPase interaction despite it being a fundamental aspect of T3SS function. In this study, we present the 2.1 Å resolution crystal structure of the Salmonella enterica SPI-2-encoded ATPase, SsaN. Our structure revealed a local and functionally important novel feature in helix 10 that we used to define the interaction domain relevant to chaperone binding. We modeled the interaction between the multicargo chaperone, SrcA, and SsaN and validated this model using mutagenesis to identify the residues on both the chaperone and ATPase that mediate the interaction. Finally, we quantified the benefit of this molecular interaction on bacterial fitness in vivo using chromosomal exchange of wild-type ssaN with mutants that retain ATPase activity but no longer capture the chaperone. Our findings provide insight into chaperone recognition by T3SS ATPases and demonstrate the importance of the chaperone-T3SS ATPase interaction for the pathogenesis of Salmonella.
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Affiliation(s)
- Sarah E Allison
- From the Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada and the Michael G. DeGroote Institute for Infectious Disease Research, Hamilton, Ontario L8S 4K1, Canada
| | - Brian R Tuinema
- From the Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada and the Michael G. DeGroote Institute for Infectious Disease Research, Hamilton, Ontario L8S 4K1, Canada
| | - Ellen S Everson
- From the Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada and the Michael G. DeGroote Institute for Infectious Disease Research, Hamilton, Ontario L8S 4K1, Canada
| | - Seiji Sugiman-Marangos
- From the Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada and the Michael G. DeGroote Institute for Infectious Disease Research, Hamilton, Ontario L8S 4K1, Canada
| | - Kun Zhang
- From the Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada and the Michael G. DeGroote Institute for Infectious Disease Research, Hamilton, Ontario L8S 4K1, Canada
| | - Murray S Junop
- From the Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada and the Michael G. DeGroote Institute for Infectious Disease Research, Hamilton, Ontario L8S 4K1, Canada
| | - Brian K Coombes
- From the Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada and the Michael G. DeGroote Institute for Infectious Disease Research, Hamilton, Ontario L8S 4K1, Canada
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Hanski L, Vuorela PM. Recent advances in technologies for developing drugs againstChlamydia pneumoniae. Expert Opin Drug Discov 2014; 9:791-802. [DOI: 10.1517/17460441.2014.915309] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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18
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Yoshida Y, Miki T, Ono S, Haneda T, Ito M, Okada N. Functional characterization of the type III secretion ATPase SsaN encoded by Salmonella pathogenicity island 2. PLoS One 2014; 9:e94347. [PMID: 24722491 PMCID: PMC3983159 DOI: 10.1371/journal.pone.0094347] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 03/12/2014] [Indexed: 02/07/2023] Open
Abstract
A type III secretion system (T3SS) is utilized by a large number of gram-negative bacteria to deliver effectors directly into the cytosol of eukaryotic host cells. One essential component of a T3SS is an ATPase that catalyzes the unfolding of proteins, which is followed by the translocation of effectors through an injectisome. Here we demonstrate a functional role of the ATPase SsaN, a component of Salmonella pathogenicity island 2 T3SS (T3SS-2) in Salmonella enterica serovar Typhimurium. SsaN hydrolyzed ATP in vitro and was essential for T3SS function and Salmonella virulence in vivo. Protein-protein interaction analyses revealed that SsaN interacted with SsaK and SsaQ to form the C ring complex. SsaN and its complex co-localized to the membrane fraction under T3SS-2 inducing conditions. In addition, SsaN bound to Salmonella pathogenicity island 2 (SPI-2) specific chaperones, including SsaE, SseA, SscA, and SscB that facilitated translocator/effector secretion. Using an in vitro chaperone release assay, we demonstrated that SsaN dissociated a chaperone-effector complex, SsaE and SseB, in an ATP-dependent manner. Effector release was dependent on a conserved arginine residue at position 192 of SsaN, and this was essential for its enzymatic activity. These results strongly suggest that the T3SS-2-associated ATPase SsaN contributes to T3SS-2 effector translocation efficiency.
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Affiliation(s)
- Yukie Yoshida
- Department of Microbiology, School of Pharmacy, Kitasato University, Tokyo, Japan
| | - Tsuyoshi Miki
- Department of Microbiology, School of Pharmacy, Kitasato University, Tokyo, Japan
| | - Sayaka Ono
- Department of Microbiology, School of Pharmacy, Kitasato University, Tokyo, Japan
| | - Takeshi Haneda
- Department of Microbiology, School of Pharmacy, Kitasato University, Tokyo, Japan
| | - Masahiro Ito
- Department of Microbiology, School of Pharmacy, Kitasato University, Tokyo, Japan
| | - Nobuhiko Okada
- Department of Microbiology, School of Pharmacy, Kitasato University, Tokyo, Japan
- * E-mail:
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EscO, a functional and structural analog of the flagellar FliJ protein, is a positive regulator of EscN ATPase activity of the enteropathogenic Escherichia coli injectisome. J Bacteriol 2014; 196:2227-41. [PMID: 24706741 DOI: 10.1128/jb.01551-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Type III secretion systems (T3SSs) are multiprotein molecular devices used by many Gram-negative bacterial pathogens to translocate effector proteins into eukaryotic cells. A T3SS is also used for protein export in flagellar assembly, which promotes bacterial motility. The two systems are evolutionarily related, possessing highly conserved components in their export apparatuses. Enteropathogenic Escherichia coli (EPEC) employs a T3SS, encoded by genes in the locus of enterocyte effacement (LEE) pathogenicity island, to colonize the human intestine and cause diarrheal disease. In the present work, we investigated the role of the LEE-encoded EscO protein (previously Orf15 or EscA) in T3SS biogenesis. We show that EscO shares similar properties with the flagellar FliJ and the Yersinia YscO protein families. Our findings demonstrate that EscO is essential for secretion of all categories of T3SS substrates. Consistent with its central role in protein secretion, it was found to interact with the ATPase EscN and its negative regulator, EscL, of the export apparatus. Moreover, we show that EscO stimulates EscN enzymatic activity; however, it is unable to upregulate ATP hydrolysis in the presence of EscL. Remarkably, EscO partially restored the swimming defect of a Salmonella flagellar fliJ mutant and was able to stimulate the ATPase activity of FliI. Overall, our data indicate that EscO is the virulence counterpart of the flagellar FliJ protein.
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Mehlitz A, Rudel T. Modulation of host signaling and cellular responses by Chlamydia. Cell Commun Signal 2013; 11:90. [PMID: 24267514 PMCID: PMC4222901 DOI: 10.1186/1478-811x-11-90] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 11/19/2013] [Indexed: 01/24/2023] Open
Abstract
Modulation of host cell signaling and cellular functions is key to intracellular survival of pathogenic bacteria. Intracellular growth has several advantages e.g. escape from the humoral immune response and access to a stable nutrient rich environment. Growth in such a preferred niche comes at the price of an ongoing competition between the bacteria and the host as well as other microbes that compete for the very same host resources. This requires specialization and constant evolution of dedicated systems for adhesion, invasion and accommodation. Interestingly, obligate intracellular bacteria of the order Chlamydiales have evolved an impressive degree of control over several important host cell functions. In this review we summarize how Chlamydia controls its host cell with a special focus on signal transduction and cellular modulation.
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Affiliation(s)
- Adrian Mehlitz
- University of Wuerzburg, Biocenter, Department of Microbiology, Am Hubland, D-97074, Wuerzburg, Germany.
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Chatterjee R, Halder PK, Datta S. Identification and molecular characterization of YsaL (Ye3555): a novel negative regulator of YsaN ATPase in type three secretion system of enteropathogenic bacteria Yersinia enterocolitica. PLoS One 2013; 8:e75028. [PMID: 24124464 PMCID: PMC3790809 DOI: 10.1371/journal.pone.0075028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 08/08/2013] [Indexed: 02/07/2023] Open
Abstract
Type Three Secretion (T3S) ATPases are involved in delivery of virulent factors from bacteria to their hosts (through injectisome) in an energy (ATP) dependent manner during pathogenesis. The activities of these ATPases are tightly controlled by their specific regulators. In Yersinia enterocolitica, YsaN was predicted as a putative ATPase of the Ysa-Ysp Type Three Secretion System (T3SS) based on sequence similarity with other T3S ATPases. However detailed study and characterization of YsaN and its regulation remains largely obscure. Here, in this study, we have successfully cloned, over-expressed, purified and characterized the molecular properties of YsaN from Yersinia enterocolitica. YsaN acts as a Mg(2+) dependent ATPase and exists in solution as higher order oligomer (dodecamer). The ATPase activity of oligomeric YsaN is several fold higher than the monomeric form. Furthermore, by employing in silico studies we have identified the existence of a negative regulator of YsaN--a hypothetical protein YE3555 (termed 'YsaL'). To verify the functionality of YsaL, we have evaluated the biochemical and biophysical properties of YsaL. Purified YsaL is dimeric in solution and strongly associates with YsaN to form a stable heterotrimeric YsaL-YsaN complex (stoichiometry--2∶1). The N terminal 6-20 residues of YsaN are invariably required for stable YsaL-YsaN complex formation. YsaL inhibited the ATPase activity of YsaN with a maximum inhibition at the molar ratio 2∶1 (YsaL: YsaN). In short, our studies provide an insight into the presence of YsaN ATPase in Yersinia enterocolitica and its regulator YsaL. Our studies also correlate the functionality of one of the existing protein interaction networks that possibly is indispensable for the energy dependent process of Ysa-Ysp T3SS in pathogenic Yersinia enterocolitica.
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Affiliation(s)
- Rakesh Chatterjee
- Structural Biology and Bioinformatics Division, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata, West Bengal, India
| | - Pranab Kumar Halder
- Structural Biology and Bioinformatics Division, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata, West Bengal, India
| | - Saumen Datta
- Structural Biology and Bioinformatics Division, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata, West Bengal, India
- * E-mail:
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22
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Gloeckl S, Ong VA, Patel P, Tyndall JDA, Timms P, Beagley KW, Allan JA, Armitage CW, Turnbull L, Whitchurch CB, Merdanovic M, Ehrmann M, Powers JC, Oleksyszyn J, Verdoes M, Bogyo M, Huston WM. Identification of a serine protease inhibitor which causes inclusion vacuole reduction and is lethal to Chlamydia trachomatis. Mol Microbiol 2013; 89:676-89. [PMID: 23796320 DOI: 10.1111/mmi.12306] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2013] [Indexed: 12/22/2022]
Abstract
The mechanistic details of the pathogenesis of Chlamydia, an obligate intracellular pathogen of global importance, have eluded scientists due to the scarcity of traditional molecular genetic tools to investigate this organism. Here we report a chemical biology strategy that has uncovered the first essential protease for this organism. Identification and application of a unique CtHtrA inhibitor (JO146) to cultures of Chlamydia resulted in a complete loss of viable elementary body formation. JO146 treatment during the replicative phase of development resulted in a loss of Chlamydia cell morphology, diminishing inclusion size, and ultimate loss of inclusions from the host cells. This completely prevented the formation of viable Chlamydia elementary bodies. In addition to its effect on the human Chlamydia trachomatis strain, JO146 inhibited the viability of the mouse strain, Chlamydia muridarum, both in vitro and in vivo. Thus, we report a chemical biology approach to establish an essential role for Chlamydia CtHtrA. The function of CtHtrA for Chlamydia appears to be essential for maintenance of cell morphology during replicative the phase and these findings provide proof of concept that proteases can be targeted for antimicrobial therapy for intracellular pathogens.
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Affiliation(s)
- Sarina Gloeckl
- Institute of Health and Biomedical Innovation and School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Kelvin Grove, Qld, 4059, Australia
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23
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Stone CB, Sugiman-Marangos S, Bulir DC, Clayden RC, Leighton TL, Slootstra JW, Junop MS, Mahony JB. Structural characterization of a novel Chlamydia pneumoniae type III secretion-associated protein, Cpn0803. PLoS One 2012; 7:e30220. [PMID: 22272312 PMCID: PMC3260263 DOI: 10.1371/journal.pone.0030220] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Accepted: 12/15/2011] [Indexed: 01/07/2023] Open
Abstract
Type III secretion (T3S) is an essential virulence factor used by gram-negative pathogenic bacteria to deliver effector proteins into the host cell to establish and maintain an intracellular infection. Chlamydia is known to use T3S to facilitate invasion of host cells but many proteins in the system remain uncharacterized. The C. trachomatis protein CT584 has previously been implicated in T3S. Thus, we analyzed the CT584 ortholog in C. pneumoniae (Cpn0803) and found that it associates with known T3S proteins including the needle-filament protein (CdsF), the ATPase (CdsN), and the C-ring protein (CdsQ). Using membrane lipid strips, Cpn0803 interacted with phosphatidic acid and phosphatidylinositol, suggesting that Cpn0803 may associate with host cells. Crystallographic analysis revealed a unique structure of Cpn0803 with a hydrophobic pocket buried within the dimerization interface that may be important for binding small molecules. Also, the binding domains on Cpn0803 for CdsN, CdsQ, and CdsF were identified using Pepscan epitope mapping. Collectively, these data suggest that Cpn0803 plays a role in T3S.
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Affiliation(s)
- Chris B. Stone
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and the Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
- Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, Canada
| | - Seiji Sugiman-Marangos
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - David C. Bulir
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and the Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
- Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, Canada
| | - Rob C. Clayden
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and the Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
- Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, Canada
| | - Tiffany L. Leighton
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and the Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
- Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, Canada
| | | | - Murray S. Junop
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - James B. Mahony
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and the Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
- Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, Canada
- * E-mail:
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24
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Fields KA, Heinzen RA, Carabeo R. The obligate intracellular lifestyle. Front Microbiol 2011; 2:99. [PMID: 21747803 PMCID: PMC3129005 DOI: 10.3389/fmicb.2011.00099] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Accepted: 04/20/2011] [Indexed: 01/03/2023] Open
Affiliation(s)
- Kenneth A Fields
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine Miami, FL, USA
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