1
|
Synthesis of resveratrol derivatives and their anti-virulence activity as T3SS inhibitors of Salmonella. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.134826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
2
|
Ijaz A, Veldhuizen EJA, Broere F, Rutten VPMG, Jansen CA. The Interplay between Salmonella and Intestinal Innate Immune Cells in Chickens. Pathogens 2021; 10:1512. [PMID: 34832668 PMCID: PMC8618210 DOI: 10.3390/pathogens10111512] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/15/2021] [Accepted: 11/15/2021] [Indexed: 12/13/2022] Open
Abstract
Salmonellosis is a common infection in poultry, which results in huge economic losses in the poultry industry. At the same time, Salmonella infections are a threat to public health, since contaminated poultry products can lead to zoonotic infections. Antibiotics as feed additives have proven to be an effective prophylactic option to control Salmonella infections, but due to resistance issues in humans and animals, the use of antimicrobials in food animals has been banned in Europe. Hence, there is an urgent need to look for alternative strategies that can protect poultry against Salmonella infections. One such alternative could be to strengthen the innate immune system in young chickens in order to prevent early life infections. This can be achieved by administration of immune modulating molecules that target innate immune cells, for example via feed, or by in-ovo applications. We aimed to review the innate immune system in the chicken intestine; the main site of Salmonella entrance, and its responsiveness to Salmonella infection. Identifying the most important players in the innate immune response in the intestine is a first step in designing targeted approaches for immune modulation.
Collapse
Affiliation(s)
- Adil Ijaz
- Division of Infectious Diseases and Immunology, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands; (A.I.); (E.J.A.V.); (F.B.); (V.P.M.G.R.)
| | - Edwin J. A. Veldhuizen
- Division of Infectious Diseases and Immunology, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands; (A.I.); (E.J.A.V.); (F.B.); (V.P.M.G.R.)
| | - Femke Broere
- Division of Infectious Diseases and Immunology, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands; (A.I.); (E.J.A.V.); (F.B.); (V.P.M.G.R.)
| | - Victor P. M. G. Rutten
- Division of Infectious Diseases and Immunology, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands; (A.I.); (E.J.A.V.); (F.B.); (V.P.M.G.R.)
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, Pretoria 0110, South Africa
| | - Christine A. Jansen
- Cell Biology and Immunology Group, Department of Animal Sciences, Wageningen University & Research, De Elst 1, 6708 PB Wageningen, The Netherlands
| |
Collapse
|
3
|
Wu Y, Yang X, Zhang D, Lu C. Myricanol Inhibits the Type III Secretion System of Salmonella enterica Serovar Typhimurium by Interfering With the DNA-Binding Activity of HilD. Front Microbiol 2020; 11:571217. [PMID: 33101243 PMCID: PMC7546796 DOI: 10.3389/fmicb.2020.571217] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 09/04/2020] [Indexed: 01/09/2023] Open
Abstract
The type III secretion system (T3SS) consists of a syringe-like export machine injecting effectors from the bacterial cytosol directly into host cells to establish infection. This mechanism is widely distributed in gram-negative bacteria and can be targeted as an innovative strategy for the developing of anti-virulence drugs. In this study, we present an effective T3SS inhibitor, myricanol, inspired by the use of folk medicinal plants traditionally used against infections. Myricanol is a cyclic diarylheptanoid isolated from the medicinal plant Myrica nagi, which is found in South and East Asia. Bioassay-guided fractionation revealed that myricanol inhibited not only the secretion of type III effector proteins of Salmonella enterica serovar Typhimurium UK-1 χ8956 (S. Typhimurium) but also the invasion of S. Typhimurium into mammalian cells, but showed no toxicity to bacterial growth or the host cells. RNA-Seq data analysis showed that the transcription of the pathogenesis-related SPI-1 gene was significantly inhibited by myricanol. Further study demonstrated that myricanol binds physically to HilD and interferes with its DNA-binding activity to the promoters of the hilA and invF genes. In conclusion, we propose that myricanol is responsible for the anti-infectious properties of M. nagi and is a novel T3SS inhibitor of S. Typhimurium through a previously unappreciated mechanism of action.
Collapse
Affiliation(s)
- Yang Wu
- Key Laboratory of Chemical Biology, Ministry of Education, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Xuefei Yang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Dongdong Zhang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Chunhua Lu
- Key Laboratory of Chemical Biology, Ministry of Education, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| |
Collapse
|
4
|
Natarajan J, Singh N, Rapaport D. Assembly and targeting of secretins in the bacterial outer membrane. Int J Med Microbiol 2019; 309:151322. [PMID: 31262642 DOI: 10.1016/j.ijmm.2019.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 06/04/2019] [Accepted: 06/18/2019] [Indexed: 11/20/2022] Open
Abstract
In Gram-negative bacteria, secretion of toxins ensure the survival of the bacterium. Such toxins are secreted by sophisticated multiprotein systems. The most conserved part in some of these secretion systems are components, called secretins, which form the outer membrane ring in these systems. Recent structural studies shed some light on the oligomeric organization of secretins. However, the mechanisms by which these proteins are targeted to the outer membrane and assemble there into ring structures are still not fully understood. This review discusses the various species-specific targeting and assembly pathways that are taken by secretins in order to form their functional oligomers.
Collapse
Affiliation(s)
- Janani Natarajan
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany.
| | - Nidhi Singh
- Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Elfriede-Aulhorn-Str.6, 72076 Tübingen, Germany
| | - Doron Rapaport
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany
| |
Collapse
|
5
|
Zhang Y, Liu Y, Wang T, Deng X, Chu X. Natural compound sanguinarine chloride targets the type III secretion system of Salmonella enterica Serovar Typhimurium. Biochem Biophys Rep 2018; 14:149-154. [PMID: 29761161 PMCID: PMC5948472 DOI: 10.1016/j.bbrep.2018.04.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 04/24/2018] [Accepted: 04/26/2018] [Indexed: 11/24/2022] Open
Abstract
The type III secretion system (T3SS) is a key virulence mechanism of many Gram-negative bacterial pathogens. Upon contact between bacteria and host cells, T3SS transfers a series of effectors from the bacterial cytosol to host cells. It is widely known that a mutation in T3SS does not impair bacterial growth, thereby avoiding any subsequent development of resistance. Thus, T3SS is expected to be a candidate therapeutic target. While developing the T3SS screening method, we discovered that sanguinarine chloride, a natural compound, could decrease the production of the SPI-1 type III secretion system main virulence proteins SipA and SipB and prevent the invasion of HeLa cells by Salmonella enterica serovar Typhimurium without affecting the growth of Salmonella. Furthermore, sanguinarine chloride downregulated the transcription of HilA and consequently regulated the expression of the SPI-1 apparatus and effector genes. In summary, our study directly demonstrated that this putative SPI-1 inhibitor belongs to a novel class of anti-Salmonella compounds. Sanguinarine chloride effectively inhibits the translocation of a SipA-Lactamase fusion into mammalian cells. Sanguinarine chloride inhibits the invasion of Hela cells by Salmonella enterica serovar Typhimurium. Sanguinarine chloride inhibits the secretion of SPI-1 virulence proteins. Sanguinarine chloride inhibits SPI-1 effectors through SPI-1 transcription regulate.
Collapse
Affiliation(s)
- Yong Zhang
- Center of Infection and Immunity, First Hospital, Jilin University, Changchun 130061, China.,Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Yan Liu
- Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Tingting Wang
- Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Xuming Deng
- Center of Infection and Immunity, First Hospital, Jilin University, Changchun 130061, China.,Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Xiao Chu
- Center of Infection and Immunity, First Hospital, Jilin University, Changchun 130061, China
| |
Collapse
|
6
|
Young AM, Palmer AE. Methods to Illuminate the Role of Salmonella Effector Proteins during Infection: A Review. Front Cell Infect Microbiol 2017; 7:363. [PMID: 28848721 PMCID: PMC5554337 DOI: 10.3389/fcimb.2017.00363] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 07/27/2017] [Indexed: 12/19/2022] Open
Abstract
Intracellular bacterial pathogens like Salmonella enterica use secretion systems, such as the Type III Secretion System, to deliver virulence factors into host cells in order to invade and colonize these cells. Salmonella virulence factors include a suite of effector proteins that remodel the host cell to facilitate bacterial internalization, replication, and evasion of host immune surveillance. A number of diverse and innovative approaches have been used to identify and characterize the role of effector proteins during infection. Recent techniques for studying infection using single cell and animal models have illuminated the contribution of individual effector proteins in infection. This review will highlight the techniques applied to study Salmonella effector proteins during infection. It will describe how different approaches have revealed mechanistic details for effectors in manipulating host cellular processes including: the dynamics of effector translocation into host cells, cytoskeleton reorganization, membrane trafficking, gene regulation, and autophagy.
Collapse
Affiliation(s)
- Alexandra M Young
- Department of Chemistry and Biochemistry, BioFrontiers Institute, University of Colorado BoulderBoulder, CO, United States
| | - Amy E Palmer
- Department of Chemistry and Biochemistry, BioFrontiers Institute, University of Colorado BoulderBoulder, CO, United States
| |
Collapse
|
7
|
Rakonjac J, Russel M, Khanum S, Brooke SJ, Rajič M. Filamentous Phage: Structure and Biology. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1053:1-20. [PMID: 29549632 DOI: 10.1007/978-3-319-72077-7_1] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Ff filamentous phage (fd, M13 and f1) of Escherichia coli have been the workhorse of phage display technology for the past 30 years. Dominance of Ff over other bacteriophage in display technology stems from the titres that are about 100-fold higher than any other known phage, efficacious transformation ensuring large library size and superior stability of the virion at high temperatures, detergents and pH extremes, allowing broad range of biopanning conditions in screening phage display libraries. Due to the excellent understanding of infection and assembly requirements, Ff phage have also been at the core of phage-assisted continual protein evolution strategies (PACE). This chapter will give an overview of the Ff filamentous phage structure and biology, emphasizing those properties of the Ff phage life cycle and virion that are pertinent to phage display applications.
Collapse
Affiliation(s)
- Jasna Rakonjac
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand. .,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.
| | | | - Sofia Khanum
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Sam J Brooke
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Marina Rajič
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| |
Collapse
|
8
|
Abstract
Type III secretion systems (T3SSs) afford Gram-negative bacteria an intimate means of altering the biology of their eukaryotic hosts--the direct delivery of effector proteins from the bacterial cytoplasm to that of the eukaryote. This incredible biophysical feat is accomplished by nanosyringe "injectisomes," which form a conduit across the three plasma membranes, peptidoglycan layer, and extracellular space that form a barrier to the direct delivery of proteins from bacterium to host. The focus of this chapter is T3SS function at the structural level; we will summarize the core findings that have shaped our understanding of the structure and function of these systems and highlight recent developments in the field. In turn, we describe the T3SS secretory apparatus, consider its engagement with secretion substrates, and discuss the posttranslational regulation of secretory function. Lastly, we close with a discussion of the future prospects for the interrogation of structure-function relationships in the T3SS.
Collapse
|
9
|
Gebauer J, Kudlackova H, Kosina M, Kovarcik K, Tesarik R, Osvaldova A, Faldyna M, Matiasovic J. A proteomic approach to the development of DIVA ELISA distinguishing pigs infected with Salmonella Typhimurium and pigs vaccinated with a Salmonella Typhimurium-based inactivated vaccine. BMC Vet Res 2016; 12:252. [PMID: 27835998 PMCID: PMC5106837 DOI: 10.1186/s12917-016-0879-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 11/03/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Salmonella enterica serovar Typhimurium is one of the most common enteropathogenic bacteria found in pigs in Europe. In our previous work, we demonstrated the protective effects in suckling piglets when their dams had been vaccinated with an S. Typhimurium-based inactivated vaccine. This study is focused on a procedure leading to serological discrimination between vaccinated and infected pigs. As we supposed, distinct environment during natural infection and in bacterial cultures used for vaccine preparation led to a slightly different spectrum of expressed S. Typhimurium proteins. The examination of porcine antibodies produced after the experimental infection with S. Typhimurium or after vaccination with S. Typhimurium-based inactivated vaccine by affinity chromatography and mass spectrometry revealed differences in antibody response applicable for serological differentiation of infected from vaccinated animals. RESULTS Antibodies against Salmonella SipB, SipD and SseB proteins were detected at much higher levels in post-infection sera in comparison with control and post-vaccination sera. On the other hand, proteins BamB, OppA and a fragment of FliC interacted with antibodies from post-vaccination sera with a much higher intensity than from control and post-infection sera. In addition, we constructed ELISA assays using post-infection antigen - SipB protein and post-vaccination antigen - FliC-fragment and evaluated them on a panel of individual porcine sera. CONCLUSIONS The analysis of antibody response of infected and vaccinated pigs by proteomic tools enabled to identify S. Typhimurium antigens useful for distinguishing infected from vaccinated animals. This approach can be utilized in other challenges where DIVA vaccine and a subsequent serological assay are required, especially when genetic modification of a vaccine strain is not desirable.
Collapse
Affiliation(s)
- Jan Gebauer
- Department of Immunology, Veterinary Research Institute, Hudcova296/70, 62100, Brno, Czech Republic. .,Department of Experimental Biology, Faculty of Science, Masaryk University, Kotlarska267/2, 611 37, Brno, Czech Republic.
| | - Hana Kudlackova
- Department of Immunology, Veterinary Research Institute, Hudcova296/70, 62100, Brno, Czech Republic
| | - Marcel Kosina
- Bioveta a. s., Komenskeho212/12, 683 23, Ivanovice na Hane, Czech Republic
| | - Kamil Kovarcik
- Department of Virology, Veterinary Research Institute, Hudcova296/70, 62100, Brno, Czech Republic
| | - Radek Tesarik
- Department of Immunology, Veterinary Research Institute, Hudcova296/70, 62100, Brno, Czech Republic
| | - Alena Osvaldova
- Department of Immunology, Veterinary Research Institute, Hudcova296/70, 62100, Brno, Czech Republic.,Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences, Palackeho 1/3, 612 42, Brno, Czech Republic
| | - Martin Faldyna
- Department of Immunology, Veterinary Research Institute, Hudcova296/70, 62100, Brno, Czech Republic
| | - Jan Matiasovic
- Department of Immunology, Veterinary Research Institute, Hudcova296/70, 62100, Brno, Czech Republic
| |
Collapse
|
10
|
McQuate SE, Young AM, Silva-Herzog E, Bunker E, Hernandez M, de Chaumont F, Liu X, Detweiler CS, Palmer AE. Long-term live-cell imaging reveals new roles for Salmonella effector proteins SseG and SteA. Cell Microbiol 2016; 19. [PMID: 27376507 DOI: 10.1111/cmi.12641] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 06/08/2016] [Accepted: 06/28/2016] [Indexed: 01/18/2023]
Abstract
Salmonella Typhimurium is an intracellular bacterial pathogen that infects both epithelial cells and macrophages. Salmonella effector proteins, which are translocated into the host cell and manipulate host cell components, control the ability to replicate and/or survive in host cells. Due to the complexity and heterogeneity of Salmonella infections, there is growing recognition of the need for single-cell and live-cell imaging approaches to identify and characterize the diversity of cellular phenotypes and how they evolve over time. Here, we establish a pipeline for long-term (17 h) live-cell imaging of infected cells and subsequent image analysis methods. We apply this pipeline to track bacterial replication within the Salmonella-containing vacuole in epithelial cells, quantify vacuolar replication versus survival in macrophages and investigate the role of individual effector proteins in mediating these parameters. This approach revealed that dispersed bacteria can coalesce at later stages of infection, that the effector protein SseG influences the propensity for cytosolic hyper-replication in epithelial cells, and that while SteA only has a subtle effect on vacuolar replication in epithelial cells, it has a profound impact on infection parameters in immunocompetent macrophages, suggesting differential roles for effector proteins in different infection models.
Collapse
Affiliation(s)
- Sarah E McQuate
- Department of Chemistry and Biochemistry, BioFrontiers Institute, University of Colorado at Boulder, Boulder, CO, USA
| | - Alexandra M Young
- Department of Chemistry and Biochemistry, BioFrontiers Institute, University of Colorado at Boulder, Boulder, CO, USA
| | - Eugenia Silva-Herzog
- Department of Chemistry and Biochemistry, BioFrontiers Institute, University of Colorado at Boulder, Boulder, CO, USA
| | - Eric Bunker
- Department of Chemistry and Biochemistry, BioFrontiers Institute, University of Colorado at Boulder, Boulder, CO, USA
| | - Mateo Hernandez
- Department of Chemistry and Biochemistry, BioFrontiers Institute, University of Colorado at Boulder, Boulder, CO, USA
| | | | - Xuedong Liu
- Department of Chemistry and Biochemistry, BioFrontiers Institute, University of Colorado at Boulder, Boulder, CO, USA
| | - Corrella S Detweiler
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO, USA
| | - Amy E Palmer
- Department of Chemistry and Biochemistry, BioFrontiers Institute, University of Colorado at Boulder, Boulder, CO, USA
| |
Collapse
|
11
|
Bulir DC, Liang S, Lee A, Chong S, Simms E, Stone C, Kaushic C, Ashkar A, Mahony JB. Immunization with chlamydial type III secretion antigens reduces vaginal shedding and prevents fallopian tube pathology following live C. muridarum challenge. Vaccine 2016; 34:3979-85. [PMID: 27325352 DOI: 10.1016/j.vaccine.2016.06.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 04/25/2016] [Accepted: 06/14/2016] [Indexed: 11/26/2022]
Abstract
Chlamydia trachomatis infections in women are often asymptomatic and if left untreated can lead to significant late sequelae including pelvic inflammatory disease and tubal factor infertility. Vaccine development efforts over the past three decades have been unproductive and there is no vaccine approved for use in humans. The existence of serologically distinct strains or serovars of C. trachomatis mandates a vaccine that will provide protection against multiple serovars. Chlamydia spp. use a highly conserved type III secretion system (T3SS) composed of both structural and effector proteins which is an essential virulence factor for infection and intracellular replication. In this study we evaluated a novel fusion protein antigen (BD584) which consists of three T3SS proteins from C. trachomatis (CopB, CopD, and CT584) as a potential chlamydial vaccine candidate. Intranasal immunization with BD584 elicited serum neutralizing antibodies that inhibited C. trachomatis infection in vitro. Following intravaginal challenge with C. muridarum, immunized mice had a 95% reduction in chlamydial shedding from the vagina at the peak of infection and cleared the infection sooner than control mice. Immunization with BD584 also reduced the rate of hydrosalpinx by 87.5% compared to control mice. Together, these results suggest that highly conserved proteins of the chlamydial T3SS may represent good candidates for a Chlamydia vaccine.
Collapse
Affiliation(s)
- David C Bulir
- M. G. DeGroote Institute for Infectious Disease Research, Canada; St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Steven Liang
- M. G. DeGroote Institute for Infectious Disease Research, Canada; St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Amanda Lee
- St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Sylvia Chong
- St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Elizabeth Simms
- St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Christopher Stone
- St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Charu Kaushic
- M. G. DeGroote Institute for Infectious Disease Research, Canada; Department of Pathology and Molecular Medicine, McMaster University, Canada
| | - Ali Ashkar
- M. G. DeGroote Institute for Infectious Disease Research, Canada; Department of Pathology and Molecular Medicine, McMaster University, Canada
| | - James B Mahony
- M. G. DeGroote Institute for Infectious Disease Research, Canada; Department of Pathology and Molecular Medicine, McMaster University, Canada; St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada.
| |
Collapse
|
12
|
Rios AC, Moutinho CG, Pinto FC, Del Fiol FS, Jozala A, Chaud MV, Vila MMDC, Teixeira JA, Balcão VM. Alternatives to overcoming bacterial resistances: State-of-the-art. Microbiol Res 2016; 191:51-80. [PMID: 27524653 DOI: 10.1016/j.micres.2016.04.008] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 03/28/2016] [Accepted: 04/21/2016] [Indexed: 12/23/2022]
Abstract
Worldwide, bacterial resistance to chemical antibiotics has reached such a high level that endangers public health. Presently, the adoption of alternative strategies that promote the elimination of resistant microbial strains from the environment is of utmost importance. This review discusses and analyses several (potential) alternative strategies to current chemical antibiotics. Bacteriophage (or phage) therapy, although not new, makes use of strictly lytic phage particles as an alternative, or a complement, in the antimicrobial treatment of bacterial infections. It is being rediscovered as a safe method, because these biological entities devoid of any metabolic machinery do not possess any affinity whatsoever to eukaryotic cells. Lysin therapy is also recognized as an innovative antimicrobial therapeutic option, since the topical administration of preparations containing purified recombinant lysins with amounts in the order of nanograms, in infections caused by Gram-positive bacteria, demonstrated a high therapeutic potential by causing immediate lysis of the target bacterial cells. Additionally, this therapy exhibits the potential to act synergistically when combined with certain chemical antibiotics already available on the market. Another potential alternative antimicrobial therapy is based on the use of antimicrobial peptides (AMPs), amphiphilic polypeptides that cause disruption of the bacterial membrane and can be used in the treatment of bacterial, fungal and viral infections, in the prevention of biofilm formation, and as antitumoral agents. Interestingly, bacteriocins are a common strategy of bacterial defense against other bacterial agents, eliminating the potential opponents of the former and increasing the number of available nutrients in the environment for their own growth. They can be applied in the food industry as biopreservatives and as probiotics, and also in fighting multi-resistant bacterial strains. The use of antibacterial antibodies promises to be extremely safe and effective. Additionally, vaccination emerges as one of the most promising preventive strategies. All these will be tackled in detail in this review paper.
Collapse
Affiliation(s)
- Alessandra C Rios
- LaBNUS-Biomaterials and Nanotechnology Laboratory, i(bs)2i(bs)(2)-intelligent biosensing and biomolecule stabilization research group, University of Sorocaba, Sorocaba/SP, Brazil
| | - Carla G Moutinho
- CEB-Centre of Biological Engineering, University of Minho, Braga, Portugal; University Fernando Pessoa, Porto, Portugal
| | | | - Fernando S Del Fiol
- LaBNUS-Biomaterials and Nanotechnology Laboratory, i(bs)2i(bs)(2)-intelligent biosensing and biomolecule stabilization research group, University of Sorocaba, Sorocaba/SP, Brazil
| | - Angela Jozala
- LaBNUS-Biomaterials and Nanotechnology Laboratory, i(bs)2i(bs)(2)-intelligent biosensing and biomolecule stabilization research group, University of Sorocaba, Sorocaba/SP, Brazil
| | - Marco V Chaud
- LaBNUS-Biomaterials and Nanotechnology Laboratory, i(bs)2i(bs)(2)-intelligent biosensing and biomolecule stabilization research group, University of Sorocaba, Sorocaba/SP, Brazil
| | - Marta M D C Vila
- LaBNUS-Biomaterials and Nanotechnology Laboratory, i(bs)2i(bs)(2)-intelligent biosensing and biomolecule stabilization research group, University of Sorocaba, Sorocaba/SP, Brazil
| | - José A Teixeira
- CEB-Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Victor M Balcão
- LaBNUS-Biomaterials and Nanotechnology Laboratory, i(bs)2i(bs)(2)-intelligent biosensing and biomolecule stabilization research group, University of Sorocaba, Sorocaba/SP, Brazil; CEB-Centre of Biological Engineering, University of Minho, Braga, Portugal.
| |
Collapse
|
13
|
McDowell MA, Marcoux J, McVicker G, Johnson S, Fong YH, Stevens R, Bowman LAH, Degiacomi MT, Yan J, Wise A, Friede ME, Benesch JLP, Deane JE, Tang CM, Robinson CV, Lea SM. Characterisation of Shigella Spa33 and Thermotoga FliM/N reveals a new model for C-ring assembly in T3SS. Mol Microbiol 2015; 99:749-66. [PMID: 26538516 PMCID: PMC4832279 DOI: 10.1111/mmi.13267] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/02/2015] [Indexed: 11/06/2022]
Abstract
Flagellar type III secretion systems (T3SS) contain an essential cytoplasmic‐ring (C‐ring) largely composed of two proteins FliM and FliN, whereas an analogous substructure for the closely related non‐flagellar (NF) T3SS has not been observed in situ. We show that the spa33 gene encoding the putative NF‐T3SS C‐ring component in Shigella flexneri is alternatively translated to produce both full‐length (Spa33‐FL) and a short variant (Spa33‐C), with both required for secretion. They associate in a 1:2 complex (Spa33‐FL/C2) that further oligomerises into elongated arrays in vitro. The structure of Spa33‐C2 and identification of an unexpected intramolecular pseudodimer in Spa33‐FL reveal a molecular model for their higher order assembly within NF‐T3SS. Spa33‐FL and Spa33‐C are identified as functional counterparts of a FliM–FliN fusion and free FliN respectively. Furthermore, we show that Thermotoga maritima
FliM and FliN form a 1:3 complex structurally equivalent to Spa33‐FL/C2, allowing us to propose a unified model for C‐ring assembly by NF‐T3SS and flagellar‐T3SS.
Collapse
Affiliation(s)
| | - Julien Marcoux
- Department of Chemistry, University of Oxford, Oxford, UK
| | - Gareth McVicker
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Steven Johnson
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Yu Hang Fong
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Rebecca Stevens
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Lesley A H Bowman
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | | | - Jun Yan
- Department of Chemistry, University of Oxford, Oxford, UK
| | - Adam Wise
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Miriam E Friede
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | | | - Janet E Deane
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Christoph M Tang
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | | | - Susan M Lea
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| |
Collapse
|
14
|
Keller B, Mühlenkamp M, Deuschle E, Siegfried A, Mössner S, Schade J, Griesinger T, Katava N, Braunsdorf C, Fehrenbacher B, Jiménez‐Soto LF, Schaller M, Haas R, Genth H, Retta SF, Meyer H, Böttcher RT, Zent R, Schütz M, Autenrieth IB, Bohn E. Yersinia enterocolitica
exploits different pathways to accomplish adhesion and toxin injection into host cells. Cell Microbiol 2015; 17:1179-204. [DOI: 10.1111/cmi.12429] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Revised: 02/05/2015] [Accepted: 02/06/2015] [Indexed: 12/12/2022]
Affiliation(s)
- Birgit Keller
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Eberhard Karls Universität Tübingen Germany
| | - Melanie Mühlenkamp
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Eberhard Karls Universität Tübingen Germany
| | - Eva Deuschle
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Eberhard Karls Universität Tübingen Germany
| | - Alexandra Siegfried
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Eberhard Karls Universität Tübingen Germany
| | - Sara Mössner
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Eberhard Karls Universität Tübingen Germany
| | - Jessica Schade
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Eberhard Karls Universität Tübingen Germany
| | - Tanja Griesinger
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Eberhard Karls Universität Tübingen Germany
| | - Nenad Katava
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Eberhard Karls Universität Tübingen Germany
| | | | | | | | - Martin Schaller
- Department of Dermatology Eberhard Karls University Tübingen Germany
| | - Rainer Haas
- Max von Pettenkofer‐Institut Ludwig‐Maximilians University Munich Germany
| | - Harald Genth
- Institute of Toxicology Medical School Hannover Hannover Germany
| | - Saverio F. Retta
- Department of Clinical and Biological Sciences University of Torino Orbassano Italy
| | - Hannelore Meyer
- Max Planck Institut für Biochemie Martinsried Germany
- Institut für Medizinische Mikrobiologie, Immunologie und Hygiene Technische Universität München Germany
| | | | - Roy Zent
- Department of Medicine (Division of Nephrology) Vanderbilt University Medical Center Nashville TN USA
| | - Monika Schütz
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Eberhard Karls Universität Tübingen Germany
- Department of Medicine (Division of Nephrology) Vanderbilt University Medical Center Nashville TN USA
| | - Ingo B. Autenrieth
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Eberhard Karls Universität Tübingen Germany
- German Centre of Infection Research (DZIF) Partner Site Tübingen Germany
| | - Erwin Bohn
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Eberhard Karls Universität Tübingen Germany
| |
Collapse
|
15
|
Iversen H, Lindbäck T, L’Abée-Lund TM, Roos N, Aspholm M, Stenfors Arnesen L. The gut bacterium Bacteroides thetaiotaomicron influences the virulence potential of the enterohemorrhagic Escherichia coli O103:H25. PLoS One 2015; 10:e0118140. [PMID: 25719195 PMCID: PMC4342160 DOI: 10.1371/journal.pone.0118140] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 12/17/2014] [Indexed: 11/18/2022] Open
Abstract
Enterohemorrhagic E. coli (EHEC) is associated with severe gastrointestinal disease. Upon entering the gastrointestinal tract, EHEC is exposed to a fluctuating environment and a myriad of other bacterial species. To establish an infection, EHEC strains have to modulate their gene expression according to the GI tract environment. In order to explore the interspecies interactions between EHEC and an human intestinal commensal, the global gene expression profile was determined of EHEC O103:H25 (EHEC NIPH-11060424) co-cultured with B. thetaiotaomicron (CCUG 10774) or grown in the presence of spent medium from B. thetaiotaomicron. Microarray analysis revealed that approximately 1% of the EHEC NIPH-11060424 genes were significantly up-regulated both in co-culture (30 genes) and in the presence of spent medium (44 genes), and that the affected genes differed between the two conditions. In co-culture, genes encoding structural components of the type three secretion system were among the most affected genes with an almost 4-fold up-regulation, while the most affected genes in spent medium were involved in chemotaxis and were more than 3-fold up-regulated. The operons for type three secretion system (TTSS) are located on the Locus of enterocyte effacement (LEE) pathogenicity island, and qPCR showed that genes of all five operons (LEE1-LEE5) were up-regulated. Moreover, an increased adherence to HeLa cells was observed in EHEC NIPH-11060424 exposed to B. thetaiotaomicron. Expression of stx2 genes, encoding the main virulence factor of EHEC, was down-regulated in both conditions (co-culture/spent medium). These results show that expression of EHEC genes involved in colonization and virulence is modulated in response to direct interspecies contact between cells, or to diffusible factors released from B. thetaiotaomicron. Such interspecies interactions could allow the pathogen to recognize its predilection site and modulate its behaviour accordingly, thus increasing the efficiency of colonization of the colon mucosa, facilitating its persistence and increasing its virulence potential.
Collapse
Affiliation(s)
- Hildegunn Iversen
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Toril Lindbäck
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Trine M. L’Abée-Lund
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Norbert Roos
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Marina Aspholm
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Lotte Stenfors Arnesen
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
- * E-mail:
| |
Collapse
|
16
|
Letchumanan V, Chan KG, Lee LH. Vibrio parahaemolyticus: a review on the pathogenesis, prevalence, and advance molecular identification techniques. Front Microbiol 2014; 5:705. [PMID: 25566219 PMCID: PMC4263241 DOI: 10.3389/fmicb.2014.00705] [Citation(s) in RCA: 280] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 11/27/2014] [Indexed: 12/13/2022] Open
Abstract
Vibrio parahaemolyticus is a Gram-negative halophilic bacterium that is found in estuarine, marine and coastal environments. V. parahaemolyticus is the leading causal agent of human acute gastroenteritis following the consumption of raw, undercooked, or mishandled marine products. In rare cases, V. parahaemolyticus causes wound infection, ear infection or septicaemia in individuals with pre-existing medical conditions. V. parahaemolyticus has two hemolysins virulence factors that are thermostable direct hemolysin (tdh)-a pore-forming protein that contributes to the invasiveness of the bacterium in humans, and TDH-related hemolysin (trh), which plays a similar role as tdh in the disease pathogenesis. In addition, the bacterium is also encodes for adhesions and type III secretion systems (T3SS1 and T3SS2) to ensure its survival in the environment. This review aims at discussing the V. parahaemolyticus growth and characteristics, pathogenesis, prevalence and advances in molecular identification techniques.
Collapse
Affiliation(s)
- Vengadesh Letchumanan
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University Bandar Sunway, Malaysia ; Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya Kuala Lumpur, Malaysia
| | - Kok-Gan Chan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya Kuala Lumpur, Malaysia
| | - Learn-Han Lee
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University Bandar Sunway, Malaysia
| |
Collapse
|
17
|
Abstract
Bacteriophage genomes found in a range of bacterial pathogens encode a diverse array of virulence factors ranging from superantigens or pore forming lysins to numerous exotoxins. Recent studies have uncovered an entirely new class of bacterial virulence factors, called effector proteins or effector toxins, which are encoded within phage genomes that reside among several pathovars of Escherichia coli and Salmonella enterica. These effector proteins have multiple domains resulting in proteins that can be multifunctional. The effector proteins encoded within phage genomes are translocated directly from the bacterial cytosol into their eukaryotic target cells by specialized bacterial type three secretion systems (T3SSs). In this review, we will give an overview of the different types of effector proteins encoded within phage genomes and examine their roles in bacterial pathogenesis.
Collapse
Affiliation(s)
- E Fidelma Boyd
- Department of Biological Sciences; University of Delaware; Newark, DE USA
| | | | | |
Collapse
|
18
|
Boumart Z, Velge P, Wiedemann A. Multiple invasion mechanisms and different intracellular Behaviors: a new vision ofSalmonella-host cell interaction. FEMS Microbiol Lett 2014; 361:1-7. [DOI: 10.1111/1574-6968.12614] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 09/16/2014] [Accepted: 09/27/2014] [Indexed: 12/20/2022] Open
Affiliation(s)
- Zineb Boumart
- Institut National de la Recherche Agronomique; UMR1282 Infectiologie et Santé Publique; Nouzilly France
- Université François Rabelais; UMR1282 Infectiologie et Santé Publique; Tours France
- Agence Nationale de Sécurité Sanitaire de l'alimentation; de l'environnement et du travail; Laboratoire de Ploufragan-Plouzané; Unité Hygiène et Qualité des Produits Avicoles et Porcins; Plouragan France
| | - Philippe Velge
- Institut National de la Recherche Agronomique; UMR1282 Infectiologie et Santé Publique; Nouzilly France
- Université François Rabelais; UMR1282 Infectiologie et Santé Publique; Tours France
| | - Agnès Wiedemann
- Institut National de la Recherche Agronomique; UMR1282 Infectiologie et Santé Publique; Nouzilly France
- Université François Rabelais; UMR1282 Infectiologie et Santé Publique; Tours France
| |
Collapse
|
19
|
Banerjee A, Dey S, Chakraborty A, Datta A, Basu A, Chakrabarti S, Datta S. Binding mode analysis of a major T3SS translocator protein PopB with its chaperone PcrH from Pseudomonas aeruginosa. Proteins 2014; 82:3273-85. [PMID: 25116453 DOI: 10.1002/prot.24666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 07/25/2014] [Accepted: 08/05/2014] [Indexed: 11/10/2022]
Abstract
Pseudomonas aeruginosa, a Gram-negative pathogen uses a specialized set of Type III secretion system (T3SS) translocator proteins to establish virulence in the host cell. An understanding of the factors that govern translocation by the translocator protein-chaperone complex is thus of immense importance. In this work, experimental and computational techniques were used to probe into the structure of the major translocator protein PopB from P. aeruginosa and to identify the important regions involved in functioning of the translocator protein. This study reveals that the binding sites of the common chaperone PcrH, needed for maintenance of the translocator PopB within the bacterial cytoplasm, which are primarily localized within the N-terminal domain. However, disordered and flexible residues located both at the N- and C-terminal domains are also observed to be involved in association with the chaperone. This intrinsic disorderliness of the terminal domains is conserved for all the major T3SS translocator proteins and is functionally important to maintain the intrinsically disordered state of the translocators. Our experimental and computational analyses suggest that a "disorder-to-order" transition of PopB protein might take place upon PcrH binding. The long helical coiled-coil part of PopB protein perhaps helps in pore formation while the flexible apical region is involved in chaperone interaction. Thus, our computational model of translocator protein PopB and its binding analyses provide crucial functional insights into the T3SS translocation mechanism.
Collapse
Affiliation(s)
- Anindyajit Banerjee
- Division of Structural Biology and Bioinformatics, Indian Institute of Chemical Biology, Council of Scientific and Industrial Research, Kolkata, 700 032, West Bengal, India
| | | | | | | | | | | | | |
Collapse
|
20
|
Effector CD8+ T cells are generated in response to an immunodominant epitope in type III effector YopE during primary Yersinia pseudotuberculosis infection. Infect Immun 2014; 82:3033-44. [PMID: 24799630 DOI: 10.1128/iai.01687-14] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
YopE is a virulence factor that is secreted into host cells infected by Yersinia species. The YopE C-terminal domain has GTPase-activating protein (GAP) activity. The YopE N-terminal domain contains an epitope that is an immunodominant CD8(+) T cell antigen during primary infection of C57BL/6 mice with Yersinia pseudotuberculosis. The characteristics of the CD8(+) T cells generated in response to the epitope, which comprises YopE amino acid residues 69 to 77 (YopE(69-77)), and the features of YopE that are important for antigenicity during primary infection, are unknown. Following intravenous infection of naïve C57BL/6 mice with a yopE GAP mutant (the R144A mutant), flow cytometry analysis of splenocytes by tetramer and intracellular cytokine staining over a time course showed that YopE69-77-specific CD8(+) T cells producing gamma interferon (IFN-γ) and tumor necrosis factor alpha (TNF-α) were generated by day 7, with a peak at day 14. In addition, ∼80% of YopE(69-77)-specific CD8(+) T cells were positive for KLRG1, a memory phenotype marker, at day 21. To determine if residues that regulate YopE activity by ubiquitination or membrane localization affect the antigenicity of YopE(69-77), mice were infected with a yopE ubiquitination or membrane localization mutant (the R62K or L55N I59N L63N mutant, respectively). These mutants elicited YopE(69-77)-specific CD8(+) T cells producing IFN-γ and TNF-α with kinetics and magnitudes similar to those of the parental R144A strain, indicating that primary infection primes effector CD8(+) T cells independently of the ubiquitination or membrane localization of YopE. Additionally, at day 7, there was an unexpected positive correlation between the numbers of YopE(69-77)-specific CD8(+) T cells and CD11b(+) cells, but not between the numbers of YopE(69-77)-specific CD8(+) T cells and bacterial cells, in spleens, suggesting that the innate immune response contributes to the immunodominance of YopE(69-77).
Collapse
|
21
|
Hochkoeppler A. Expanding the landscape of recombinant protein production in Escherichia coli. Biotechnol Lett 2013; 35:1971-81. [DOI: 10.1007/s10529-013-1396-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 06/26/2013] [Indexed: 12/11/2022]
|
22
|
The Aeromonas salmonicida subsp. salmonicida exoproteome: determination of the complete repertoire of Type-Three Secretion System effectors and identification of other virulence factors. Proteome Sci 2013; 11:42. [PMID: 24073886 PMCID: PMC3852671 DOI: 10.1186/1477-5956-11-42] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 09/23/2013] [Indexed: 01/24/2023] Open
Abstract
Background Aeromonas salmonicida subsp. salmonicida, the etiologic agent of furunculosis, is a major pathogen of fisheries worldwide. Several virulence factors have been described, but the type-three secretion system (T3SS) is recognized as having a major effect on virulence by injecting effectors directly into fish cells. In this study we used high-throughput proteomics to display the differences between in vitro secretome of A. salmonicida wild-type (wt, hypervirulent, JF2267) and T3SS-deficient (isogenic ΔascV, extremely low-virulent, JF2747) strains in exponential and stationary phases of growth. Results Results confirmed the secretion of effectors AopH, AexT, AopP and AopO via T3SS, and for the first time demonstrated the impact of T3SS in secretion of Ati2, AopN and ExsE that are known as effectors in other pathogens. Translocators, needle subunits, Ati1, and AscX were also secreted in supernatants (SNs) dependent on T3SS. AopH, Ati2, AexT, AopB and AopD were in the top seven most abundant excreted proteins. EF-G, EF-Tu, DnaK, HtpG, PNPase, PepN and MdeA were moderately secreted in wt SNs and predicted to be putative T3 effectors by bioinformatics. Pta and ASA_P5G088 were increased in wt SNs and T3-associated in other bacteria. Ten conserved cytoplasmic proteins were more abundant in wt SNs than in the ΔascV mutant, but without any clear association to a secretion system. T1-secreted proteins were predominantly found in wt SNs: OmpAI, OmpK40, DegQ, insulinase ASA_0716, hypothetical ASA_0852 and ASA_3619. Presence of T3SS components in pellets was clearly decreased by ascV deletion, while no impact was observed on T1- and T2SS. Our results demonstrated that the ΔascV mutant strain excreted well-described (VapA, AerA, AerB, GCAT, Pla1, PlaC, TagA, Ahe2, GbpA and enolase) and yet uncharacterized potential toxins, adhesins and enzymes as much as or even more than the wt strain. Other putative important virulence factors were not detected. Conclusions We demonstrated the whole in vitro secretome and T3SS repertoire of hypervirulent A. salmonicida. Several toxins, adhesins and enzymes that are not part of the T3SS secretome were secreted to a higher extent in the extremely low-virulent ΔascV mutant. All together, our results show the high importance of an intact T3SS to initiate the furunculosis and offer new information about the pathogenesis.
Collapse
|
23
|
Abstract
Secretion of effectors across bacterial membranes is usually mediated by large multisubunit complexes. In most cases, the secreted effectors are virulent factors normally associated to pathogenic diseases. The biogenesis of these secretion systems and the transport of the effectors are processes that require energy. This energy could be directly obtained by using the proton motive force, but in most cases the energy associated to these processes is derived from ATP hydrolysis. Here, a description of the machineries involved in generating the energy required for system biogenesis and substrate transport by type II, III and IV secretion systems is provided, with special emphasis on highlighting the structural similarities and evolutionary relationships among the secretion ATPases.
Collapse
Affiliation(s)
- Alejandro Peña
- Departamento de Biología Molecular, Universidad de Cantabria, UC-CSIC-SODERCAN, Santander, Spain
| | | |
Collapse
|
24
|
Demers JP, Sgourakis NG, Gupta R, Loquet A, Giller K, Riedel D, Laube B, Kolbe M, Baker D, Becker S, Lange A. The common structural architecture of Shigella flexneri and Salmonella typhimurium type three secretion needles. PLoS Pathog 2013; 9:e1003245. [PMID: 23555258 PMCID: PMC3605151 DOI: 10.1371/journal.ppat.1003245] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 01/23/2013] [Indexed: 11/25/2022] Open
Abstract
The Type Three Secretion System (T3SS), or injectisome, is a macromolecular infection machinery present in many pathogenic Gram-negative bacteria. It consists of a basal body, anchored in both bacterial membranes, and a hollow needle through which effector proteins are delivered into the target host cell. Two different architectures of the T3SS needle have been previously proposed. First, an atomic model of the Salmonella typhimurium needle was generated from solid-state NMR data. The needle subunit protein, PrgI, comprises a rigid-extended N-terminal segment and a helix-loop-helix motif with the N-terminus located on the outside face of the needle. Second, a model of the Shigella flexneri needle was generated from a high-resolution 7.7-Å cryo-electron microscopy density map. The subunit protein, MxiH, contains an N-terminal α-helix, a loop, another α-helix, a 14-residue-long β-hairpin (Q51–Q64) and a C-terminal α-helix, with the N-terminus facing inward to the lumen of the needle. In the current study, we carried out solid-state NMR measurements of wild-type Shigella flexneri needles polymerized in vitro and identified the following secondary structure elements for MxiH: a rigid-extended N-terminal segment (S2-T11), an α-helix (L12-A38), a loop (E39-P44) and a C-terminal α-helix (Q45-R83). Using immunogold labeling in vitro and in vivo on functional needles, we located the N-terminus of MxiH subunits on the exterior of the assembly, consistent with evolutionary sequence conservation patterns and mutagenesis data. We generated a homology model of Shigella flexneri needles compatible with both experimental data: the MxiH solid-state NMR chemical shifts and the state-of-the-art cryoEM density map. These results corroborate the solid-state NMR structure previously solved for Salmonella typhimurium PrgI needles and establish that Shigella flexneri and Salmonella typhimurium subunit proteins adopt a conserved structure and orientation in their assembled state. Our study reveals a common structural architecture of T3SS needles, essential to understand T3SS-mediated infection and develop treatments. Gram-negative bacteria use a molecular machinery called the Type Three Secretion System (T3SS) to deliver toxic proteins to the host cell. Our research group has recently solved the structure of the extracellular T3SS needle of Salmonella typhimurium. Employing solid-state NMR, we could determine local structure parameters such as dihedral angles and inter-nuclear proximities for this supramolecular assembly. Concurrently, a high-resolution cryo-electron microscopy density map of the T3SS needle of Shigella flexneri was obtained by Fujii et al. Modeling of the Shigella needle subunit protein to fit the EM density produced a model incompatible with the atomic model of the Salmonella needle in terms of secondary structure and subunit orientation. Here, we determined directly the secondary structure of the Shigella needle subunit using solid-state NMR, and its orientation using in vitro and in vivo immunogold labeling in functional needles. We found that Shigella subunits adopt the same secondary structure and orientation as in the atomic model of Salmonella, and we generated a homology model of the Shigella needle consistent with the EM density. Knowing the common T3SS needle architecture is essential for understanding the secretion mechanism and interactions of the needle with other components of the T3SS, and to develop therapeutics.
Collapse
Affiliation(s)
- Jean-Philippe Demers
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Nikolaos G. Sgourakis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Rashmi Gupta
- Department for Cellular Microbiology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Antoine Loquet
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Karin Giller
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Dietmar Riedel
- Laboratory for Electron Microscopy, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Britta Laube
- Core Facility Microscopy, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Michael Kolbe
- Department for Cellular Microbiology, Max Planck Institute for Infection Biology, Berlin, Germany
- * E-mail: (MK); (DB); (SB); (AL)
| | - David Baker
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- * E-mail: (MK); (DB); (SB); (AL)
| | - Stefan Becker
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- * E-mail: (MK); (DB); (SB); (AL)
| | - Adam Lange
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- * E-mail: (MK); (DB); (SB); (AL)
| |
Collapse
|
25
|
Cytosporone B, an inhibitor of the type III secretion system of Salmonella enterica serovar Typhimurium. Antimicrob Agents Chemother 2013; 57:2191-8. [PMID: 23459474 DOI: 10.1128/aac.02421-12] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Bacterial virulence factors have been increasingly regarded as attractive targets for development of novel antibacterial agents. Virulence inhibitors are less likely to generate bacterial resistance, which makes them superior to traditional antibiotics that target bacterial viability. Salmonella enterica serovar Typhimurium, an important food-borne human pathogen, has type III secretion system (T3SS) as its major virulence factor. T3SS secretes effector proteins to facilitate invasion into host cells. In this study, we identified several analogs of cytosporone B (Csn-B) that strongly block the secretion of Salmonella pathogenicity island 1 (SPI-1)-associated effector proteins, without affecting the secretion of flagellar protein FliC in vitro. Csn-B and two other derivatives exhibited a strong inhibitory effect on SPI-1-mediated invasion to HeLa cells, while no significant toxicity to bacteria was observed. Nucleoid proteins Hha and H-NS bind to the promoters of SPI-1 regulator genes hilD, hilC, and rtsA to repress their expression and consequently regulate the expression of SPI-1 apparatus and effector genes. We found that Csn-B upregulated the transcription of hha and hns, implying that Csn-B probably affected the secretion of effectors through the Hha-H-NS regulatory pathway. In summary, this study presented an effective SPI-1 inhibitor, Csn-B, which may have potential in drug development against antibiotic-resistant Salmonella.
Collapse
|
26
|
Moest TP, Méresse S. Salmonella T3SSs: successful mission of the secret(ion) agents. Curr Opin Microbiol 2013; 16:38-44. [DOI: 10.1016/j.mib.2012.11.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 11/15/2012] [Accepted: 11/26/2012] [Indexed: 10/27/2022]
|
27
|
Tsou LK, Dossa PD, Hang HC. Small molecules aimed at type III secretion systems to inhibit bacterial virulence. MEDCHEMCOMM 2013; 4:68-79. [PMID: 23930198 DOI: 10.1039/c2md20213a] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The development of new anti-bacterial compounds presents a major challenge to modern medicine as bacterial strains resistant to traditional antibiotics are constantly emerging.
Collapse
Affiliation(s)
- Lun K Tsou
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY 10065, USA
| | | | | |
Collapse
|
28
|
Abrusci P, Vergara–Irigaray M, Johnson S, Beeby MD, Hendrixson D, Roversi P, Friede ME, Deane JE, Jensen GJ, Tang CM, Lea SM. Architecture of the major component of the type III secretion system export apparatus. Nat Struct Mol Biol 2013; 20:99-104. [PMID: 23222644 PMCID: PMC3537844 DOI: 10.1038/nsmb.2452] [Citation(s) in RCA: 167] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 10/22/2012] [Indexed: 12/20/2022]
Abstract
Type III secretion systems (T3SSs) are bacterial membrane-embedded nanomachines designed to export specifically targeted proteins from the bacterial cytoplasm. Secretion through T3SS is governed by a subset of inner membrane proteins termed the 'export apparatus'. We show that a key member of the Shigella flexneri export apparatus, MxiA, assembles into a ring essential for secretion in vivo. The ring-forming interfaces are well-conserved in both nonflagellar and flagellar homologs, implying that the ring is an evolutionarily conserved feature in these systems. Electron cryo-tomography revealed a T3SS-associated cytoplasmic torus of size and shape corresponding to those of the MxiA ring aligned to the secretion channel located between the secretion pore and the ATPase complex. This defines the molecular architecture of the dominant component of the export apparatus and allows us to propose a model for the molecular mechanisms controlling secretion.
Collapse
Affiliation(s)
- Patrizia Abrusci
- Sir William Dunn School of Pathology, Oxford University, Oxford, United Kingdom
| | - Marta Vergara–Irigaray
- Sir William Dunn School of Pathology, Oxford University, Oxford, United Kingdom
- Centre for Molecular Microbiology and Infection, Imperial College London, London, United Kingdom
| | - Steven Johnson
- Sir William Dunn School of Pathology, Oxford University, Oxford, United Kingdom
| | - Morgan D Beeby
- Department of Biology, California Institute of Technology, Pasadena, California, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California, USA
| | - David Hendrixson
- Department of Microbiology, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Pietro Roversi
- Sir William Dunn School of Pathology, Oxford University, Oxford, United Kingdom
| | - Miriam E Friede
- Sir William Dunn School of Pathology, Oxford University, Oxford, United Kingdom
| | - Janet E Deane
- Sir William Dunn School of Pathology, Oxford University, Oxford, United Kingdom
| | - Grant J Jensen
- Department of Biology, California Institute of Technology, Pasadena, California, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California, USA
| | - Christoph M Tang
- Sir William Dunn School of Pathology, Oxford University, Oxford, United Kingdom
| | - Susan M Lea
- Sir William Dunn School of Pathology, Oxford University, Oxford, United Kingdom
| |
Collapse
|
29
|
Markkula E, Hulkkonen J, Penttilä T, Puolakkainen M. Host cell Golgi anti-apoptotic protein (GAAP) and growth of Chlamydia pneumoniae. Microb Pathog 2013; 54:46-53. [DOI: 10.1016/j.micpath.2012.09.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 09/03/2012] [Accepted: 09/10/2012] [Indexed: 01/01/2023]
|
30
|
Singh SK, Boyle AL, Main ERG. LcrH, a class II chaperone from the type three secretion system, has a highly flexible native structure. J Biol Chem 2012; 288:4048-55. [PMID: 23233673 DOI: 10.1074/jbc.m112.395889] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The type three secretion system is a large and complex protein nano-machine that many Gram-negative pathogens employ to infect host cells. A key structure of this machine is a proteinaceous pore that inserts into the target membrane and forms a channel for bacterial toxins to flow from bacteria into the host cell. The pore is mainly formed from two large membrane proteins called "translocators." Importantly, effective secretion and thus pore formation of the translocators depend on their binding to and being transported by small specialized chaperones after synthesis in the bacterial cytosol. Recent crystal structures have shown these chaperones are formed from modular tetratricopeptide repeats. However, each crystal structure produced different homodimeric structures, suggesting flexibility in their topology that may be of importance to function. Given the crucial role of the translocator chaperones, we investigated the conformational stability of the chaperone LcrH (Yersinia pestis). Mutational analysis coupled with analytical ultracentrifugation and equilibrium denaturations showed that LcrH is a weak and thermodynamically unstable dimer (K(D) ≈15 μm, ΔG(H(2)O) = 7.4 kcal mol(-1)). The modular tetratricopeptide repeat structure of the dimer allows it to readily unfold in a noncooperative manner to a one-third unfolded dimeric intermediate (ΔG(H(2)O) = 1.7 kcal mol(-1)), before cooperatively unfolding to a monomeric denatured state (ΔG(H(2)O) = 5.7 kcal mol(-1)). Thus, under physiological conditions, the chaperone is able to populate C-terminally unraveled partially folded states, while being held together by its dimeric interface. Such ability suggests a "fly-casting" mechanism as a route to binding their far larger translocator cargo.
Collapse
Affiliation(s)
- Sunny K Singh
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, UK
| | | | | |
Collapse
|
31
|
Förster resonance energy transfer (FRET) as a tool for dissecting the molecular mechanisms for maturation of the Shigella type III secretion needle tip complex. Int J Mol Sci 2012. [PMID: 23203116 PMCID: PMC3509632 DOI: 10.3390/ijms131115137] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Förster resonance energy transfer (FRET) provides a powerful tool for monitoring intermolecular interactions and a sensitive technique for studying Å-level protein conformational changes. One system that has particularly benefited from the sensitivity and diversity of FRET measurements is the maturation of the Shigella type III secretion apparatus (T3SA) needle tip complex. The Shigella T3SA delivers effector proteins into intestinal cells to promote bacterial invasion and spread. The T3SA is comprised of a basal body that spans the bacterial envelope and a needle with an exposed tip complex that matures in response to environmental stimuli. FRET measurements demonstrated bile salt binding by the nascent needle tip protein IpaD and also mapped resulting structural changes which led to the recruitment of the translocator IpaB. At the needle tip IpaB acts as a sensor for host cell contact but prior to secretion, it is stored as a heterodimeric complex with the chaperone IpgC. FRET analyses showed that chaperone binding to IpaB’s N-terminal domain causes a conformational change in the latter. These FRET analyses, with other biophysical methods, have been central to understanding T3SA maturation and will be highlighted, focusing on the details of the FRET measurements and the relevance to this particular system.
Collapse
|
32
|
Thanassi DG, Bliska JB, Christie PJ. Surface organelles assembled by secretion systems of Gram-negative bacteria: diversity in structure and function. FEMS Microbiol Rev 2012; 36:1046-82. [PMID: 22545799 PMCID: PMC3421059 DOI: 10.1111/j.1574-6976.2012.00342.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Revised: 03/08/2012] [Accepted: 04/13/2012] [Indexed: 11/29/2022] Open
Abstract
Gram-negative bacteria express a wide variety of organelles on their cell surface. These surface structures may be the end products of secretion systems, such as the hair-like fibers assembled by the chaperone/usher (CU) and type IV pilus pathways, which generally function in adhesion to surfaces and bacterial-bacterial and bacterial-host interactions. Alternatively, the surface organelles may be integral components of the secretion machinery itself, such as the needle complex and pilus extensions formed by the type III and type IV secretion systems, which function in the delivery of bacterial effectors inside host cells. Bacterial surface structures perform functions critical for pathogenesis and have evolved to withstand forces exerted by the external environment and cope with defenses mounted by the host immune system. Given their essential roles in pathogenesis and exposed nature, bacterial surface structures also make attractive targets for therapeutic intervention. This review will describe the structure and function of surface organelles assembled by four different Gram-negative bacterial secretion systems: the CU pathway, the type IV pilus pathway, and the type III and type IV secretion systems.
Collapse
Affiliation(s)
- David G Thanassi
- Center for Infectious Diseases, Stony Brook University, Stony Brook, NY 11794-5120, USA.
| | | | | |
Collapse
|
33
|
Protein export according to schedule: architecture, assembly, and regulation of type III secretion systems from plant- and animal-pathogenic bacteria. Microbiol Mol Biol Rev 2012; 76:262-310. [PMID: 22688814 DOI: 10.1128/mmbr.05017-11] [Citation(s) in RCA: 299] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Flagellar and translocation-associated type III secretion (T3S) systems are present in most gram-negative plant- and animal-pathogenic bacteria and are often essential for bacterial motility or pathogenicity. The architectures of the complex membrane-spanning secretion apparatuses of both systems are similar, but they are associated with different extracellular appendages, including the flagellar hook and filament or the needle/pilus structures of translocation-associated T3S systems. The needle/pilus is connected to a bacterial translocon that is inserted into the host plasma membrane and mediates the transkingdom transport of bacterial effector proteins into eukaryotic cells. During the last 3 to 5 years, significant progress has been made in the characterization of membrane-associated core components and extracellular structures of T3S systems. Furthermore, transcriptional and posttranscriptional regulators that control T3S gene expression and substrate specificity have been described. Given the architecture of the T3S system, it is assumed that extracellular components of the secretion apparatus are secreted prior to effector proteins, suggesting that there is a hierarchy in T3S. The aim of this review is to summarize our current knowledge of T3S system components and associated control proteins from both plant- and animal-pathogenic bacteria.
Collapse
|
34
|
Prehna G, Li Y, Stoynov N, Okon M, Vuckovic M, McIntosh LP, Foster LJ, Finlay BB, Strynadka NCJ. The zinc regulated antivirulence pathway of Salmonella is a multiprotein immunoglobulin adhesion system. J Biol Chem 2012; 287:32324-37. [PMID: 22810234 DOI: 10.1074/jbc.m112.357210] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The co-evolutionary relationship between pathogen and host has led to a regulatory cycle between virulence factors needed for survival and antivirulence factors required for host transmission. This is exemplified in Salmonella spp. by the zirTS antivirulence genes: a secretion pathway comprised of the outer membrane transporter ZirT, and its secreted partner, ZirS. ZirTS act within the gastrointestinal tract to function as a virulence modulator and during Salmonella shedding in anticipation of a new host. Together, ZirT and ZirS decrease virulence by lowering bacterial colonization at systemic sites through an unknown mechanism. To understand this mechanism, we have probed the zirTS pathway both structurally and biochemically. The NMR derived structural ensemble of the C-terminal domain of ZirS reveals an immunoglobin superfamily fold (IgSF). Stable isotope labeling by amino acids in cell culture experiments show that the ZirS IgSF domain interacts with its transporter ZirT, and reveal a new protein interaction partner of the pathway, a protein encoded adjacent to zirTS that we have designated as ZirU. ZirU is secreted by ZirT and is also a predicted IgSF. Biochemical analysis delineates ZirT into an N-terminal porin-like β domain and C-terminal extracellular soluble IgSF domain, whereas biophysical characterization suggests that the transporter undergoes self-association in a concentration-dependent manner. We observe that ZirS and ZirU directly interact with each other and with the extracellular domains of ZirT. Here we show that the zir antivirulence pathway is a multiprotein immunoglobulin adhesion system consisting of a complex interplay between ZirS, ZirT, and ZirU.
Collapse
Affiliation(s)
- Gerd Prehna
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver V6T 1Z3 BC, Canada
| | | | | | | | | | | | | | | | | |
Collapse
|
35
|
|
36
|
The bimodal lifestyle of intracellular Salmonella in epithelial cells: replication in the cytosol obscures defects in vacuolar replication. PLoS One 2012; 7:e38732. [PMID: 22719929 PMCID: PMC3374820 DOI: 10.1371/journal.pone.0038732] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 05/10/2012] [Indexed: 11/29/2022] Open
Abstract
Salmonella enterica serovar Typhimurium invades and proliferates within epithelial cells. Intracellular bacteria replicate within a membrane bound vacuole known as the Salmonella containing vacuole. However, this bacterium can also replicate efficiently in the cytosol of epithelial cells and net intracellular growth is a product of both vacuolar and cytosolic replication. Here we have used semi-quantitative single-cell analyses to investigate the contribution of each of these replicative niches to intracellular proliferation in cultured epithelial cells. We show that cytosolic replication can account for the majority of net replication even though it occurs in less than 20% of infected cells. Consequently, assays for net growth in a population of infected cells, for example by recovery of colony forming units, are not good indicators of vacuolar proliferation. We also show that the Salmonella Type III Secretion System 2, which is required for SCV biogenesis, is not required for cytosolic replication. Altogether this study illustrates the value of single cell analyses when studying intracellular pathogens.
Collapse
|
37
|
Barrett LG, Heil M. Unifying concepts and mechanisms in the specificity of plant-enemy interactions. TRENDS IN PLANT SCIENCE 2012; 17:282-92. [PMID: 22465042 DOI: 10.1016/j.tplants.2012.02.009] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2011] [Revised: 02/13/2012] [Accepted: 02/28/2012] [Indexed: 05/08/2023]
Abstract
Host ranges are commonly quantified to classify herbivores and plant pathogens as either generalists or specialists. Here, we summarize patterns and mechanisms in the interactions of plants with these enemies along different axes of specificity. We highlight the many dimensions within which plant enemies can specify and consider the underlying ecological, evolutionary and molecular mechanisms. Host resistance traits and enemy effectors emerge as central players determining host utilization and thus host range. Finally, we review approaches to studying the causes and consequences of variation in the specificity of plant-enemy interactions. Knowledge of the molecular mechanisms that determine host range is required to understand host shifts, and evolutionary transitions among specialist and generalist strategies, and to predict potential host ranges of pathogens and herbivores.
Collapse
Affiliation(s)
- Luke G Barrett
- CSIRO Plant Industry, GPO Box 1600, Canberra ACT, 2601, Australia
| | | |
Collapse
|
38
|
Gendrin C, Contreras-Martel C, Bouillot S, Elsen S, Lemaire D, Skoufias DA, Huber P, Attree I, Dessen A. Structural basis of cytotoxicity mediated by the type III secretion toxin ExoU from Pseudomonas aeruginosa. PLoS Pathog 2012; 8:e1002637. [PMID: 22496657 PMCID: PMC3320612 DOI: 10.1371/journal.ppat.1002637] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 02/25/2012] [Indexed: 11/30/2022] Open
Abstract
The type III secretion system (T3SS) is a complex macromolecular machinery employed by a number of Gram-negative pathogens to inject effectors directly into the cytoplasm of eukaryotic cells. ExoU from the opportunistic pathogen Pseudomonas aeruginosa is one of the most aggressive toxins injected by a T3SS, leading to rapid cell necrosis. Here we report the crystal structure of ExoU in complex with its chaperone, SpcU. ExoU folds into membrane-binding, bridging, and phospholipase domains. SpcU maintains the N-terminus of ExoU in an unfolded state, required for secretion. The phospholipase domain carries an embedded catalytic site whose position within ExoU does not permit direct interaction with the bilayer, which suggests that ExoU must undergo a conformational rearrangement in order to access lipids within the target membrane. The bridging domain connects catalytic domain and membrane-binding domains, the latter of which displays specificity to PI(4,5)P2. Both transfection experiments and infection of eukaryotic cells with ExoU-secreting bacteria show that ExoU ubiquitination results in its co-localization with endosomal markers. This could reflect an attempt of the infected cell to target ExoU for degradation in order to protect itself from its aggressive cytotoxic action. Pseudomonas aeruginosa is a leading cause of nosocomial infections and is a particular threat for cystic fibrosis and immunodepressed patients. One of the most aggressive toxins in its arsenal is ExoU, injected directly into target cells by a needle-like complex located on the surface of the bacterium, the type III secretion system. P. aeruginosa strains that express ExoU cause rapid cell death as a consequence of the membrane-destruction (phospholipase) potential of the toxin. In this work, we report the three-dimensional structure of ExoU in complex with a partner molecule, SpcU. ExoU contains three distinct regions, and the fold suggests how ExoU binds to the membrane or other molecules within the target cell and becomes activated. In addition, we also show that once it is translocated into the cell, ExoU co-localizes with intracellular organelles of the endosomal pathway, potentially in an attempt of the target cell to destroy the toxin. This work provides new insight into the cellular destruction mechanism of this aggressive toxin and could be a basis for the development of new inhibitors of P. aeruginosa pathogenesis.
Collapse
Affiliation(s)
- Claire Gendrin
- Bacterial Pathogenesis Group, Institut de Biologie Structurale (IBS), Université Grenoble I, Grenoble, France
- Commissariat à l'Enérgie Atomique (CEA), Grenoble and Cadarache, France
- Centre National de la Recherche Scientifique (CNRS), Grenoble and Cadarache, France
| | - Carlos Contreras-Martel
- Bacterial Pathogenesis Group, Institut de Biologie Structurale (IBS), Université Grenoble I, Grenoble, France
- Commissariat à l'Enérgie Atomique (CEA), Grenoble and Cadarache, France
- Centre National de la Recherche Scientifique (CNRS), Grenoble and Cadarache, France
| | - Stéphanie Bouillot
- Commissariat à l'Enérgie Atomique (CEA), Grenoble and Cadarache, France
- Centre National de la Recherche Scientifique (CNRS), Grenoble and Cadarache, France
- Bacterial Pathogenesis and Cellular Responses, iRTSV, Université Grenoble I, Grenoble, France
- INSERM UMR-S 1036, Biology of Cancer and Infection, Grenoble, France
| | - Sylvie Elsen
- Commissariat à l'Enérgie Atomique (CEA), Grenoble and Cadarache, France
- Centre National de la Recherche Scientifique (CNRS), Grenoble and Cadarache, France
- Bacterial Pathogenesis and Cellular Responses, iRTSV, Université Grenoble I, Grenoble, France
- INSERM UMR-S 1036, Biology of Cancer and Infection, Grenoble, France
| | - David Lemaire
- Commissariat à l'Enérgie Atomique (CEA), Grenoble and Cadarache, France
- Centre National de la Recherche Scientifique (CNRS), Grenoble and Cadarache, France
- Laboratoire des Interactions Protéine Métal, IBEB, Université Aix-Marseille II, Saint Paul Lez Durance, France
| | - Dimitrios A. Skoufias
- Commissariat à l'Enérgie Atomique (CEA), Grenoble and Cadarache, France
- Centre National de la Recherche Scientifique (CNRS), Grenoble and Cadarache, France
- Viral Infection and Cancer Group, IBS, Grenoble, France
| | - Philippe Huber
- Commissariat à l'Enérgie Atomique (CEA), Grenoble and Cadarache, France
- Centre National de la Recherche Scientifique (CNRS), Grenoble and Cadarache, France
- Bacterial Pathogenesis and Cellular Responses, iRTSV, Université Grenoble I, Grenoble, France
- INSERM UMR-S 1036, Biology of Cancer and Infection, Grenoble, France
| | - Ina Attree
- Commissariat à l'Enérgie Atomique (CEA), Grenoble and Cadarache, France
- Centre National de la Recherche Scientifique (CNRS), Grenoble and Cadarache, France
- Bacterial Pathogenesis and Cellular Responses, iRTSV, Université Grenoble I, Grenoble, France
- INSERM UMR-S 1036, Biology of Cancer and Infection, Grenoble, France
| | - Andréa Dessen
- Bacterial Pathogenesis Group, Institut de Biologie Structurale (IBS), Université Grenoble I, Grenoble, France
- Commissariat à l'Enérgie Atomique (CEA), Grenoble and Cadarache, France
- Centre National de la Recherche Scientifique (CNRS), Grenoble and Cadarache, France
- * E-mail:
| |
Collapse
|
39
|
Role of antigens and virulence factors of Salmonella enterica serovar Typhi in its pathogenesis. Microbiol Res 2012; 167:199-210. [DOI: 10.1016/j.micres.2011.08.001] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 08/05/2011] [Accepted: 08/08/2011] [Indexed: 12/25/2022]
|
40
|
Auweter SD, Yu HB, Arena ET, Guttman JA, Finlay BB. Oxysterol-binding protein (OSBP) enhances replication of intracellular Salmonella and binds the Salmonella SPI-2 effector SseL via its N-terminus. Microbes Infect 2012; 14:148-54. [DOI: 10.1016/j.micinf.2011.09.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 09/03/2011] [Accepted: 09/16/2011] [Indexed: 11/15/2022]
|
41
|
Paramasivam N, Linke D. ClubSub-P: Cluster-Based Subcellular Localization Prediction for Gram-Negative Bacteria and Archaea. Front Microbiol 2011; 2:218. [PMID: 22073040 PMCID: PMC3210502 DOI: 10.3389/fmicb.2011.00218] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 10/12/2011] [Indexed: 12/17/2022] Open
Abstract
The subcellular localization (SCL) of proteins provides important clues to their function in a cell. In our efforts to predict useful vaccine targets against Gram-negative bacteria, we noticed that misannotated start codons frequently lead to wrongly assigned SCLs. This and other problems in SCL prediction, such as the relatively high false-positive and false-negative rates of some tools, can be avoided by applying multiple prediction tools to groups of homologous proteins. Here we present ClubSub-P, an online database that combines existing SCL prediction tools into a consensus pipeline from more than 600 proteomes of fully sequenced microorganisms. On top of the consensus prediction at the level of single sequences, the tool uses clusters of homologous proteins from Gram-negative bacteria and from Archaea to eliminate false-positive and false-negative predictions. ClubSub-P can assign the SCL of proteins from Gram-negative bacteria and Archaea with high precision. The database is searchable, and can easily be expanded using either new bacterial genomes or new prediction tools as they become available. This will further improve the performance of the SCL prediction, as well as the detection of misannotated start codons and other annotation errors. ClubSub-P is available online at http://toolkit.tuebingen.mpg.de/clubsubp/
Collapse
Affiliation(s)
- Nagarajan Paramasivam
- Department I Protein Evolution, Max Planck Institute for Developmental Biology Tübingen, Germany
| | | |
Collapse
|
42
|
A protective epitope in type III effector YopE is a major CD8 T cell antigen during primary infection with Yersinia pseudotuberculosis. Infect Immun 2011; 80:206-14. [PMID: 22064714 DOI: 10.1128/iai.05971-11] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Virulence in human-pathogenic Yersinia species is associated with a plasmid-encoded type III secretion system that translocates a set of Yop effector proteins into host cells. One effector, YopE, functions as a Rho GTPase-activating protein (GAP). In addition to acting as a virulence factor, YopE can function as a protective antigen. C57BL/6 mice infected with attenuated Yersinia pestis generate a dominant H2-Kb-restricted CD8 T cell response to an epitope in the N-terminal domain of YopE (YopE69-77), and intranasal vaccination with the YopE69-77 peptide and the mucosal adjuvant cholera toxin (CT) elicits CD8 T cells that are protective against lethal pulmonary challenge with Y. pestis. Because YopE69-77 is conserved in many Yersinia strains, we sought to determine if YopE is a protective antigen for Yersinia pseudotuberculosis and if primary infection with this enteric pathogen elicits a CD8 T cell response to this epitope. Intranasal immunization with the YopE69-77 peptide and CT elicited a CD8 T cell response that was protective against lethal intragastric Y. pseudotuberculosis challenge. The YopE69-77 epitope was a major antigen (∼30% of splenic CD8 T cells were specific for this peptide at the peak of the response) during primary infection with Y. pseudotuberculosis, as shown by flow cytometry tetramer staining. Results of infections with Y. pseudotuberculosis expressing catalytically inactive YopE demonstrated that GAP activity is dispensable for a CD8 T cell response to YopE69-77. Determining the features of YopE that are important for this response will lead to a better understanding of how protective CD8 T cell immunity is generated against Yersinia and other pathogens with type III secretion systems.
Collapse
|
43
|
Broberg CA, Calder TJ, Orth K. Vibrio parahaemolyticus cell biology and pathogenicity determinants. Microbes Infect 2011; 13:992-1001. [PMID: 21782964 PMCID: PMC3384537 DOI: 10.1016/j.micinf.2011.06.013] [Citation(s) in RCA: 247] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 06/15/2011] [Accepted: 06/17/2011] [Indexed: 10/18/2022]
Abstract
Vibrio parahaemolyticus is a significant cause of gastroenteritis worldwide. Characterization of this pathogen has revealed a unique repertoire of virulence factors that allow for colonization of the human host and disease. The following describes the known pathogenicity determinants while establishing the need for continued research.
Collapse
Affiliation(s)
- Christopher A. Broberg
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas TX 75390-9148, USA
| | - Thomas J. Calder
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas TX 75390-9148, USA
| | - Kim Orth
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas TX 75390-9148, USA
| |
Collapse
|
44
|
Disulfide bonding within components of the Chlamydia type III secretion apparatus correlates with development. J Bacteriol 2011; 193:6950-9. [PMID: 22001510 DOI: 10.1128/jb.05163-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chlamydia spp. exhibit a unique biphasic developmental cycle whereby infectious elementary bodies (EBs) invade host epithelial cells and differentiate into noninfectious, metabolically active reticulate bodies (RBs). EBs posses a unique outer envelope where rigidity is achieved by disulfide bonding among cysteine-rich envelope-associated proteins. Conversely, these disulfide bonds become reduced in RBs to accommodate vegetative growth, thereby linking the redox status of cysteine-rich envelope proteins with progression of the developmental cycle. We investigated the potential role of disulfide bonding within the chlamydial type III secretion system (T3SS), since activity of this system is also closely linked to development. We focused on structural components of the T3S apparatus that contain an unusually high number of cysteine residues compared to orthologs in other secretion systems. Nonreducing SDS-PAGE revealed that EB-localized apparatus proteins such as CdsF, CdsD, and CdsC form higher-order complexes mediated by disulfide bonding. The most dramatic alterations were detected for the needle protein CdsF. Significantly, disulfide bonding patterns shifted during differentiation of developmental forms and were completely reduced in RBs. Furthermore, at later time points during infection following RB to EB conversion, we found that CdsF is reoxidized into higher-order complexes. Overall, we conclude that the redox status of specific T3SS apparatus proteins is intimately linked to the developmental cycle and constitutes a newly appreciated aspect of functionally significant alterations within proteins of the chlamydial envelope.
Collapse
|
45
|
Izoré T, Job V, Dessen A. Biogenesis, regulation, and targeting of the type III secretion system. Structure 2011; 19:603-12. [PMID: 21565695 DOI: 10.1016/j.str.2011.03.015] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 03/28/2011] [Accepted: 03/29/2011] [Indexed: 01/21/2023]
Abstract
The type III secretion system (T3SS) is employed by a number of Gram-negative bacterial pathogens to inject toxins into eukaryotic cells. The biogenesis of this complex machinery requires the regulated interaction between over 20 cytosolic, periplasmic, and membrane-imbedded proteins, many of which undergo processes such as polymerization, partner recognition, and partial unfolding. Elements of this intricate macromolecular system have been characterized through electron microscopy, crystallography, and NMR techniques, allowing for an initial understanding of the spatiotemporal regulation of T3SS-related events. Here, we report recent advances in the structural characterization of T3SS proteins from a number of bacteria, and provide an overview of recently identified small molecule T3SS inhibitors that could potentially be explored for novel antibacterial development.
Collapse
Affiliation(s)
- Thierry Izoré
- Bacterial Pathogenesis Group, Institut de Biologie Structurale, Université Grenoble I, 38027 Grenoble, France
| | | | | |
Collapse
|
46
|
Darkoh C, DuPont HL. Unraveling the Role of Host Endocytic Proteins in Pedestal Formation During Enteropathogenic Escherichia coli Infection. J Infect Dis 2011; 204:667-8. [DOI: 10.1093/infdis/jir391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
47
|
Malik-Kale P, Jolly CE, Lathrop S, Winfree S, Luterbach C, Steele-Mortimer O. Salmonella - at home in the host cell. Front Microbiol 2011; 2:125. [PMID: 21687432 PMCID: PMC3109617 DOI: 10.3389/fmicb.2011.00125] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Accepted: 05/19/2011] [Indexed: 11/16/2022] Open
Abstract
The Gram-negative bacterium Salmonella enterica has developed an array of sophisticated tools to manipulate the host cell and establish an intracellular niche, for successful propagation as a facultative intracellular pathogen. While Salmonella exerts diverse effects on its host cell, only the cell biology of the classic “trigger”-mediated invasion process and the subsequent development of the Salmonella-containing vacuole have been investigated extensively. These processes are dependent on cohorts of effector proteins translocated into host cells by two type III secretion systems (T3SS), although T3SS-independent mechanisms of entry may be important for invasion of certain host cell types. Recent studies into the intracellular lifestyle of Salmonella have provided new insights into the mechanisms used by this pathogen to modulate its intracellular environment. Here we discuss current knowledge of Salmonella-host interactions including invasion and establishment of an intracellular niche within the host.
Collapse
Affiliation(s)
- Preeti Malik-Kale
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Disease, National Institute of Health Hamilton, MT, USA
| | | | | | | | | | | |
Collapse
|
48
|
Biochemical and localization analyses of putative type III secretion translocator proteins CopB and CopB2 of Chlamydia trachomatis reveal significant distinctions. Infect Immun 2011; 79:3036-45. [PMID: 21606186 DOI: 10.1128/iai.00159-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Chlamydia spp. are among the many pathogenic Gram-negative bacteria that employ a type III secretion system (T3SS) to overcome host defenses and exploit available resources. Significant progress has been made in elucidating contributions of T3S to the pathogenesis of these medically important, obligate intracellular parasites, yet important questions remain. Chief among these is how secreted effector proteins traverse eukaryotic membranes to gain access to the host cytosol. Due to a complex developmental cycle, it is possible that chlamydiae utilize a different complement of proteins to accomplish translocation at different stages of development. We investigated this possibility by extending the characterization of C. trachomatis CopB and CopB2. CopB is detected early during infection but is depleted and not detected again until about 20 h postinfection. In contrast, CopB2 was detectible throughout development. CopB is associated with the inclusion membrane. Biochemical and ectopic expression analyses were consistent with peripheral association of CopB2 with inclusion membranes. This interaction correlated with development and required both chlamydial de novo protein synthesis and T3SS activity. Collectively, our data indicate that it is unlikely that CopB serves as the sole chlamydial translocation pore and that CopB2 is capable of association with the inclusion membrane.
Collapse
|
49
|
Korotkov KV, Gonen T, Hol WGJ. Secretins: dynamic channels for protein transport across membranes. Trends Biochem Sci 2011; 36:433-43. [PMID: 21565514 DOI: 10.1016/j.tibs.2011.04.002] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 04/06/2011] [Accepted: 04/08/2011] [Indexed: 12/16/2022]
Abstract
Secretins form megadalton bacterial-membrane channels in at least four sophisticated multiprotein systems that are crucial for translocation of proteins and assembled fibers across the outer membrane of many species of bacteria. Secretin subunits contain multiple domains, which interact with numerous other proteins, including pilotins, secretion-system partner proteins, and exoproteins. Our understanding of the structure of secretins is rapidly progressing, and it is now recognized that features common to all secretins include a cylindrical arrangement of 12-15 subunits, a large periplasmic vestibule with a wide opening at one end and a periplasmic gate at the other. Secretins might also play a key role in the biogenesis of their cognate secretion systems.
Collapse
|
50
|
Alonzo F, Xayarath B, Whisstock JC, Freitag NE. Functional analysis of the Listeria monocytogenes secretion chaperone PrsA2 and its multiple contributions to bacterial virulence. Mol Microbiol 2011; 80:1530-48. [PMID: 21545417 DOI: 10.1111/j.1365-2958.2011.07665.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
As an organism that has evolved to live in environments ranging from soil to the cytosol of mammalian cells, Listeria monocytogenes must regulate the secretion and activity of protein products that promote survival within these habitats. The post-translocation chaperone PrsA2 has been adapted to assist in the folding and activity of L. monocytogenes secreted proteins required for bacterial replication within host cells. Here we present the first structure/function investigation of the contributions of PrsA2 to protein secretion and activity as well as to bacterial virulence. Domain swap experiments with the closely related L. monocytogenes PrsA1 protein combined with targeted mutagenesis indicate distinct functional roles for the PrsA2 peptidyl-prolyl isomerase (PPIase) and the N- and C-terminal domains in pathogenesis. In contrast to other PrsA-like proteins described thus far in the literature, an absolute in vivo requirement for PrsA2 PPIase activity is evident in mouse infection models. This work illustrates the diversity of function associated with L. monocytogenes PrsA2 that serves to promote bacterial life within the infected host.
Collapse
Affiliation(s)
- Francis Alonzo
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL, USA
| | | | | | | |
Collapse
|