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Cianciotto NP. The type II secretion system as an underappreciated and understudied mediator of interbacterial antagonism. Infect Immun 2024; 92:e0020724. [PMID: 38980047 PMCID: PMC11320942 DOI: 10.1128/iai.00207-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/10/2024] Open
Abstract
Interbacterial antagonism involves all major phyla, occurs across the full range of ecological niches, and has great significance for the environment, clinical arena, and agricultural and industrial sectors. Though the earliest insight into interbacterial antagonism traces back to the discovery of antibiotics, a paradigm shift happened when it was learned that protein secretion systems (e.g., types VI and IV secretion systems) deliver toxic "effectors" against competitors. However, a link between interbacterial antagonism and the Gram-negative type II secretion system (T2SS), which exists in many pathogens and environmental species, is not evident in prior reviews on bacterial competition or T2SS function. A current examination of the literature revealed four examples of a T2SS or one of its known substrates having a bactericidal activity against a Gram-positive target or another Gram-negative. When further studied, the T2SS effectors proved to be peptidases that target the peptidoglycan of the competitor. There are also reports of various bacteriolytic enzymes occurring in the culture supernatants of some other Gram-negative species, and a link between these bactericidal activities and T2SS is suggested. Thus, a T2SS can be a mediator of interbacterial antagonism, and it is possible that many T2SSs have antibacterial outputs. Yet, at present, the T2SS remains relatively understudied for its role in interbacterial competition. Arguably, there is a need to analyze the T2SSs of a broader range of species for their role in interbacterial antagonism. Such investigation offers, among other things, a possible pathway toward developing new antimicrobials for treating disease.
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Affiliation(s)
- Nicholas P. Cianciotto
- Department of Microbiology-Immunology, Northwestern University School of Medicine, Chicago, Illinois, USA
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Type IV Pili Are a Critical Virulence Factor in Clinical Isolates of Paenibacillus thiaminolyticus. mBio 2022; 13:e0268822. [PMID: 36374038 PMCID: PMC9765702 DOI: 10.1128/mbio.02688-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Hydrocephalus, the leading indication for childhood neurosurgery worldwide, is particularly prevalent in low- and middle-income countries. Hydrocephalus preceded by an infection, or postinfectious hydrocephalus, accounts for up to 60% of hydrocephalus in these areas. Since many children with hydrocephalus suffer poor long-term outcomes despite surgical intervention, prevention of hydrocephalus remains paramount. Our previous studies implicated a novel bacterial pathogen, Paenibacillus thiaminolyticus, as a causal agent of neonatal sepsis and postinfectious hydrocephalus in Uganda. Here, we report the isolation of three P. thiaminolyticus strains, Mbale, Mbale2, and Mbale3, from patients with postinfectious hydrocephalus. We constructed complete genome assemblies of the clinical isolates as well as the nonpathogenic P. thiaminolyticus reference strain and performed comparative genomic and proteomic analyses to identify potential virulence factors. All three isolates carry a unique beta-lactamase gene, and two of the three isolates exhibit resistance in culture to the beta-lactam antibiotics penicillin and ampicillin. In addition, a cluster of genes carried on a mobile genetic element that encodes a putative type IV pilus operon is present in all three clinical isolates but absent in the reference strain. CRISPR-mediated deletion of the gene cluster substantially reduced the virulence of the Mbale strain in mice. Comparative proteogenomic analysis identified various additional potential virulence factors likely acquired on mobile genetic elements in the virulent strains. These results provide insight into the emergence of virulence in P. thiaminolyticus and suggest avenues for the diagnosis and treatment of this novel bacterial pathogen. IMPORTANCE Postinfectious hydrocephalus, a devastating sequela of neonatal infection, is associated with increased childhood mortality and morbidity. A novel bacterial pathogen, Paenibacillus thiaminolyticus, is highly associated with postinfectious hydrocephalus in an African cohort. Whole-genome sequencing, RNA sequencing, and proteomics of clinical isolates and a reference strain in combination with CRISPR editing identified type IV pili as a critical virulence factor for P. thiaminolyticus infection. Acquisition of a type IV pilus-encoding mobile genetic element critically contributed to converting a nonpathogenic strain of P. thiaminolyticus into a pathogen capable of causing devastating diseases. Given the widespread presence of type IV pilus in pathogens, the presence of the type IV pilus operon could serve as a diagnostic and therapeutic target in P. thiaminolyticus and related bacteria.
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Osawa M, Erickson HP. Turgor Pressure and Possible Constriction Mechanisms in Bacterial Division. Front Microbiol 2018; 9:111. [PMID: 29445369 PMCID: PMC5797765 DOI: 10.3389/fmicb.2018.00111] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 01/17/2018] [Indexed: 12/15/2022] Open
Abstract
Bacterial cytokinesis begins with the assembly of FtsZ into a Z ring at the center of the cell. The Z-ring constriction in Gram-negative bacteria may occur in an environment where the periplasm and the cytoplasm are isoosmotic, but in Gram-positive bacteria the constriction may have to overcome a substantial turgor pressure. We address three potential sources of invagination force. (1) FtsZ itself may generate force by curved protofilaments bending the attached membrane. This is sufficient to constrict liposomes in vitro. However, this force is on the order of a few pN, and would not be enough to overcome turgor. (2) Cell wall (CW) synthesis may generate force by pushing the plasma membrane from the outside. However, this would probably require some kind of Brownian ratchet to separate the CW and membrane sufficiently to allow a glycan strand to slip in. The elastic element is not obvious. (3) Excess membrane production has the potential to contribute significantly to the invagination force. If the excess membrane is produced under the CW, it would force the membrane to bleb inward. We propose here that a combination of FtsZ pulling from the inside, and excess membrane pushing membrane inward may generate a substantial constriction force at the division site. This combined force generation mechanism may be sufficient to overcome turgor pressure. This would abolish the need for a Brownian ratchet for CW growth, and would permit CW to operate by reinforcing the constrictions generated by FtsZ and excess membrane.
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Affiliation(s)
- Masaki Osawa
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States
| | - Harold P Erickson
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States
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Kaur J, Kumar A, Kaur J. Strategies for optimization of heterologous protein expression in E. coli: Roadblocks and reinforcements. Int J Biol Macromol 2018; 106:803-822. [DOI: 10.1016/j.ijbiomac.2017.08.080] [Citation(s) in RCA: 126] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 08/02/2017] [Accepted: 08/12/2017] [Indexed: 12/29/2022]
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Kaur J, Kumar A, Kaur J. Strategies for optimization of heterologous protein expression in E. coli: Roadblocks and reinforcements. Int J Biol Macromol 2018. [DOI: 10.1016/j.ijbiomac.2017.08.080 10.1242/jeb.069716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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6
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Ng D, Harn T, Altindal T, Kolappan S, Marles JM, Lala R, Spielman I, Gao Y, Hauke CA, Kovacikova G, Verjee Z, Taylor RK, Biais N, Craig L. The Vibrio cholerae Minor Pilin TcpB Initiates Assembly and Retraction of the Toxin-Coregulated Pilus. PLoS Pathog 2016; 12:e1006109. [PMID: 27992883 PMCID: PMC5207764 DOI: 10.1371/journal.ppat.1006109] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 01/03/2017] [Accepted: 12/02/2016] [Indexed: 01/03/2023] Open
Abstract
Type IV pilus (T4P) systems are complex molecular machines that polymerize major pilin proteins into thin filaments displayed on bacterial surfaces. Pilus functions require rapid extension and depolymerization of the pilus, powered by the assembly and retraction ATPases, respectively. A set of low abundance minor pilins influences pilus dynamics by unknown mechanisms. The Vibrio cholerae toxin-coregulated pilus (TCP) is among the simplest of the T4P systems, having a single minor pilin TcpB and lacking a retraction ATPase. Here we show that TcpB, like its homolog CofB, initiates pilus assembly. TcpB co-localizes with the pili but at extremely low levels, equivalent to one subunit per pilus. We used a micropillars assay to demonstrate that TCP are retractile despite the absence of a retraction ATPase, and that retraction relies on TcpB, as a V. cholerae tcpB Glu5Val mutant is fully piliated but does not induce micropillars movements. This mutant is impaired in TCP-mediated autoagglutination and TcpF secretion, consistent with retraction being required for these functions. We propose that TcpB initiates pilus retraction by incorporating into the growing pilus in a Glu5-dependent manner, which stalls assembly and triggers processive disassembly. These results provide a framework for understanding filament dynamics in more complex T4P systems and the closely related Type II secretion system. Bacterial pathogens utilize a number of highly complex and sophisticated molecular systems to colonize their hosts and alter them, creating customized niches in which to reproduce. One such system is the Type IV pilus system, made up of dozens of proteins that form a macromolecular machine to polymerize small pilin proteins into long thin filaments that are displayed on the bacterial surface. These pili have a remarkable array of functions that rely on their ability to (i) adhere to many substrates, including host cell surfaces, pili from nearby bacteria, DNA and bacterial viruses (bacteriophage), and (ii) to depolymerize or retract, which pulls the bacteria along mucosal surfaces, pulls them close together in protective aggregates, and can even draw in substrates like DNA and bacteriophage for nutrition and genetic variation. For most Type IV pilus systems, retraction is an energy-driven process facilitated by a retraction ATPase. We show here that in the simplest of the Type IV pilus systems, the Vibrio cholerae toxin-coregulated pilus, a pilin-like protein initiates pilus retraction by what appears to be mechanical rather than enzymatic means. Our results provide a framework for understanding more complex Type IV pili and the related Type II secretion systems, which represent targets for novel highly specific antibiotics.
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Affiliation(s)
- Dixon Ng
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Tony Harn
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Tuba Altindal
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Subramania Kolappan
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Jarrad M. Marles
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Rajan Lala
- Biology Department, Brooklyn College, City University of New York, Brooklyn, New York, United States of America
| | - Ingrid Spielman
- Biology Department, Brooklyn College, City University of New York, Brooklyn, New York, United States of America
| | - Yang Gao
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Caitlyn A. Hauke
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Gabriela Kovacikova
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Zia Verjee
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Ronald K. Taylor
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Nicolas Biais
- Biology Department, Brooklyn College, City University of New York, Brooklyn, New York, United States of America
- Graduate Center, City University of New York, Brooklyn, New York, United States of America
- * E-mail: (LC); (NB)
| | - Lisa Craig
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
- * E-mail: (LC); (NB)
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A thermophilic-like ene-reductase originating from an acidophilic iron oxidizer. Appl Microbiol Biotechnol 2016; 101:609-619. [DOI: 10.1007/s00253-016-7782-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 07/21/2016] [Accepted: 08/03/2016] [Indexed: 01/25/2023]
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8
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Rigi G, Mohammadi SG, Arjomand MR, Ahmadian G, Noghabi KA. Optimization of extracellular truncated staphylococcal protein A expression inEscherichia coliBL21 (DE3). Biotechnol Appl Biochem 2014; 61:217-25. [DOI: 10.1002/bab.1157] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 09/07/2013] [Indexed: 12/12/2022]
Affiliation(s)
- Garshasb Rigi
- Department of Molecular Genetics; National Institute of Genetic Engineering and Biotechnology (NIGEB); Tehran Iran
| | - Samira Ghaed Mohammadi
- Department of Molecular Genetics; National Institute of Genetic Engineering and Biotechnology (NIGEB); Tehran Iran
| | - Maryam Rezaei Arjomand
- Department of Molecular Genetics; National Institute of Genetic Engineering and Biotechnology (NIGEB); Tehran Iran
| | - Gholamreza Ahmadian
- Department of Molecular Genetics; National Institute of Genetic Engineering and Biotechnology (NIGEB); Tehran Iran
| | - Kambiz Akbari Noghabi
- Department of Molecular Genetics; National Institute of Genetic Engineering and Biotechnology (NIGEB); Tehran Iran
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Tan JS, Ramanan RN, Ling TC, Mustafa S, Ariff AB. The role of lac operon and lac repressor in the induction using lactose for the expression of periplasmic human interferon-α2b by Escherichia coli. ANN MICROBIOL 2011. [DOI: 10.1007/s13213-011-0394-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Study on Improvement of Extracellular Production of Recombinant Thermobifida fusca Cutinase by Escherichia coli. Appl Biochem Biotechnol 2011; 165:666-75. [DOI: 10.1007/s12010-011-9286-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Accepted: 05/06/2011] [Indexed: 11/25/2022]
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11
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Puertas JM, Nannenga BL, Dornfeld KT, Betton JM, Baneyx F. Enhancing the secretory yields of leech carboxypeptidase inhibitor in Escherichia coli: influence of trigger factor and signal recognition particle. Protein Expr Purif 2010; 74:122-8. [PMID: 20600941 DOI: 10.1016/j.pep.2010.06.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Revised: 06/07/2010] [Accepted: 06/17/2010] [Indexed: 11/29/2022]
Abstract
The signal recognition particle (SRP) dependent secretion pathway is as an attractive alternative to Sec-dependent export for the production of disulfide-bonded and/or fast-folding recombinant proteins in the Escherichia coli periplasm. SRP, which shares a ribosomal attachment site with the molecular chaperone trigger factor (TF), recognizes highly hydrophobic signal sequence as they emerge from the ribosome and delivers ribosome nascent chain complexes to FtsY for subsequent cotranslational translocation of target proteins across the SecYEG pore. However, like in the case of Sec-dependent export, secretory yields can be limited by the accumulation of precursor proteins in the cytoplasm. Using leech carboxypeptidase inhibitor (LCI) fused to the SRP-dependent DsbA signal sequence as a model system, we show that a null mutation in the gene encoding TF (Deltatig) or SRP co-expression reduce pre-LCI accumulation by half, and that quantitative export can be achieved by combining the two strategies. Interestingly, enhanced precursor processing did not alter periplasmic LCI levels but increased the amount of protein excreted in the growth medium. All mature LCI was nearly fully active and an 80% increase in productivity was achieved in Deltatig cells alone due to their faster growth. Our results show that competition between SRP and TF can interfere with efficient export of recombinant proteins targeted to the SRP pathway and establish TF-deficient strains and SRP co-expression as a simple solution to improve yields.
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Affiliation(s)
- Juan-Miguel Puertas
- Department of Chemical Engineering, University of Washington, Seattle, WA 98195-1750, USA
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12
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The haloprotease CPI produced by the moderately halophilic bacterium Pseudoalteromonas ruthenica is secreted by the type II secretion pathway. Appl Environ Microbiol 2009; 75:4197-201. [PMID: 19376897 DOI: 10.1128/aem.00156-09] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The gene (cpo) encoding the extracellular protease CPI produced by the moderately halophilic bacterium Pseudoalteromonas ruthenica CP76 was cloned, and its nucleotide sequence was analyzed. The cpo gene encodes a 733-residue protein showing sequence similarity to metalloproteases of the M4 family. The type II secretion apparatus was shown to be responsible for secretion of the haloprotease CPI.
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Kulkarni R, Dhakal BK, Slechta ES, Kurtz Z, Mulvey MA, Thanassi DG. Roles of putative type II secretion and type IV pilus systems in the virulence of uropathogenic Escherichia coli. PLoS One 2009; 4:e4752. [PMID: 19270734 PMCID: PMC2649431 DOI: 10.1371/journal.pone.0004752] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Accepted: 02/05/2009] [Indexed: 01/17/2023] Open
Abstract
Background Type II secretion systems (T2SS) and the evolutionarily related type IV pili (T4P) are important virulence determinants in many Gram-negative bacterial pathogens. However, the roles of T2SS and T4P in the virulence of extraintestinal pathogenic Escherichia coli have not been determined. Methodology/Principal Findings To investigate the functions of putative T2SS and T4P gene clusters present in the model uropathogenic E. coli (UPEC) strains UTI89 and CFT073, we deleted the secretin gene present in each cluster. The secretin forms a channel in the outer membrane that is essential for the function of T2S and T4P systems. We compared the secretin deletion mutants with their wild type counterparts using tissue culture assays and the CBA/J mouse model of ascending urinary tract infection. No deficiencies were observed with any of the mutants in adherence, invasion or replication in human bladder or kidney cell lines, but UTI89 ΔhofQ and UTI89 ΔgspD exhibited approximately 2-fold defects in fluxing out of bladder epithelial cells. In the mouse infection model, each of the knockout mutants was able to establish successful infections in the bladder and kidneys by day one post-infection. However, UTI89 ΔhofQ and a CFT073 ΔhofQ ΔyheF double mutant both exhibited defects in colonizing the kidneys by day seven post-infection. Conclusions/Significance Based on our results, we propose that the putative T4P and T2S systems are virulence determinants of UPEC important for persistence in the urinary tract, particularly in renal tissues.
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Affiliation(s)
- Ritwij Kulkarni
- Center for Infectious Diseases, Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
| | - Bijaya K. Dhakal
- Department of Pathology, Division of Cell Biology and Immunology, University of Utah, Salt Lake City, Utah, United States of America
| | - E. Susan Slechta
- Department of Pathology, Division of Cell Biology and Immunology, University of Utah, Salt Lake City, Utah, United States of America
| | - Zachary Kurtz
- Center for Infectious Diseases, Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
| | - Matthew A. Mulvey
- Department of Pathology, Division of Cell Biology and Immunology, University of Utah, Salt Lake City, Utah, United States of America
| | - David G. Thanassi
- Center for Infectious Diseases, Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
- * E-mail:
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Gazi AD, Charova SN, Panopoulos NJ, Kokkinidis M. Coiled-coils in type III secretion systems: structural flexibility, disorder and biological implications. Cell Microbiol 2009; 11:719-29. [PMID: 19215225 DOI: 10.1111/j.1462-5822.2009.01297.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recent structural studies and analyses of microbial genomes have consolidated the understanding of the structural and functional versatility of coiled-coil domains in proteins from bacterial type III secretion systems (T3SS). Such domains consist of two or more α-helices forming a bundle structure. The occurrence of coiled-coils in T3SS is considerably higher than the average predicted occurrence in prokaryotic proteomes. T3SS proteins comprising coiled-coil domains are frequently characterized by an increased structural flexibility, which may vary from localized structural disorder to the establishment of molten globule-like state. The propensity for coiled-coil formation and structural disorder are frequently essential requirements for various T3SS functions, including the establishment of protein-protein interaction networks and the polymerization of extracellular components of T3SS appendages. Possible correlations between the frequently observed N-terminal structural disorder of effectors and the T3SS secretion signal are discussed. The results for T3SS are also compared with other Gram-negative secretory systems.
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Affiliation(s)
- Anastasia D Gazi
- Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology and Department of Biology, University of Crete, Vasilika Vouton, Heraklion, Crete, Greece
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15
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Evans FF, Egan S, Kjelleberg S. Ecology of type II secretion in marine gammaproteobacteria. Environ Microbiol 2008; 10:1101-7. [DOI: 10.1111/j.1462-2920.2007.01545.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Li C, Zhu Y, Benz I, Schmidt MA, Chen W, Mulchandani A, Qiao C. Presentation of functional organophosphorus hydrolase fusions on the surface ofEscherichia coliby the AIDA-I autotransporter pathway. Biotechnol Bioeng 2008; 99:485-90. [PMID: 17615561 DOI: 10.1002/bit.21548] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We report, the surface presentation of organophosphorus hydrolase (OPH) and green fluorescent protein (GFP) fusions by employing the adhesin-involved-in-diffuse-adherence (AIDA-I) translocator domain as a transporter and anchoring motif. The surface location of the OPH-GFP fusion protein was confirmed by immunofluorescence microscopy, and protease accessibility, followed by Western blotting analysis. The investigation of growth kinetics and stability of resting cultures showed that the presence of the AIDA-I translocator domain in the outer membrane neither inhibits cell growth nor affects cell viability. Furthermore, the surface-exposed OPH-GFP was shown to have enzymatic activity and a functional fluorescence moiety. These results suggest that AIDA-I autotransporter is a useful tool to present heterologous macromolecule passenger proteins on the bacterial surface. Our strategy of linking GFP to OPH and the possibility to employ various bacterial species as host has enormous potential for enhancing field use.
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Affiliation(s)
- Chaokun Li
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China
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Emanuelsson O, Brunak S, von Heijne G, Nielsen H. Locating proteins in the cell using TargetP, SignalP and related tools. Nat Protoc 2007; 2:953-71. [PMID: 17446895 DOI: 10.1038/nprot.2007.131] [Citation(s) in RCA: 2458] [Impact Index Per Article: 144.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Determining the subcellular localization of a protein is an important first step toward understanding its function. Here, we describe the properties of three well-known N-terminal sequence motifs directing proteins to the secretory pathway, mitochondria and chloroplasts, and sketch a brief history of methods to predict subcellular localization based on these sorting signals and other sequence properties. We then outline how to use a number of internet-accessible tools to arrive at a reliable subcellular localization prediction for eukaryotic and prokaryotic proteins. In particular, we provide detailed step-by-step instructions for the coupled use of the amino-acid sequence-based predictors TargetP, SignalP, ChloroP and TMHMM, which are all hosted at the Center for Biological Sequence Analysis, Technical University of Denmark. In addition, we describe and provide web references to other useful subcellular localization predictors. Finally, we discuss predictive performance measures in general and the performance of TargetP and SignalP in particular.
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Affiliation(s)
- Olof Emanuelsson
- Stockholm Bioinformatics Center, Albanova, Stockholm University, SE-10691 Stockholm, Sweden
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Ghosh J, Caparon MG. Specificity of Streptococcus pyogenes NAD(+) glycohydrolase in cytolysin-mediated translocation. Mol Microbiol 2006; 62:1203-14. [PMID: 17042787 DOI: 10.1111/j.1365-2958.2006.05430.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The mechanism by which the cytolysin-mediated translocation (CMT) pathway of the Gram-positive pathogen Streptococcus pyogenes injects effector proteins into the cytosol of an infected host cell via the pore-forming protein streptolysin O is unknown. Key questions include whether the pathway can discriminate between different substrates for translocation, and whether the effector protein plays an active or passive role in the translocation process. Here we show that CMT can discriminate between a known effector of the pathway, the S. pyogenes NAD(+) glycohydrolase (SPN), and a second secreted protein, the mitogenic factor (MF), routing the former into the host cell cytosol and the latter into the extracellular milieu. Residues within the amino-terminal 190 residues of SPN were essential for discrimination, as deletions within this domain produced proteins that retained full enzymatic activity, but were completely uncoupled from the translocation pathway. The enzymatic domain itself played a pivotal role in the discrimination as deletions within this domain also produced translocation incompetent proteins and the conversion of MF to a translocation-competent form required fusion with both SPN domains in a contiguous orientation. These data establish that CMT is discriminatory, and that SPN is a multidomain protein that plays an active role in its translocation.
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Affiliation(s)
- Joydeep Ghosh
- Department of Molecular Microbiology, Washington University School of Medicine, Box 8230, Saint Louis, MO 63110, USA
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Roy Chowdhury P, Heinemann JA. The general secretory pathway of Burkholderia gladioli pv. agaricicola BG164R is necessary for cavity disease in white button mushrooms. Appl Environ Microbiol 2006; 72:3558-65. [PMID: 16672503 PMCID: PMC1472315 DOI: 10.1128/aem.72.5.3558-3565.2006] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Cavity disease in white button mushrooms is caused by Burkholderia gladioli pv. agaricicola. We describe the isolation and characterization of six mutants of the strain BG164R that no longer cause this disease on mushrooms. The mutations were mapped to genes of the general secretory pathway (GSP). This is the first report of the association of the type II secretion pathway with a disease in mushrooms. Phenotypes of the six avirulent mutants were the following: an inability to degrade mushroom tissue, a highly reduced capacity to secrete chitinase and protease, and a reduced number of flagella. Using these mutants, we also made the novel observation that the factors causing mushroom tissue degradation, thereby leading to the expression of cavity disease, can be separated from mycelium inhibition because avirulent mutants continued to inhibit the growth of actively growing mushroom mycelia. The GSP locus of B. gladioli was subsequently cloned and mapped and compared to the same locus in closely related species, establishing that the genetic organization of the gsp operon of B. gladioli pv. agaricicola is consistent with that of other species of the genus. We also identify the most common indigenous bacterial population present in the mushroom fruit bodies from a New Zealand farm, one of which, Ewingella americana, was found to be an apparent antagonist of B. gladioli pv. agaricicola. While other investigators have reported enhanced disease symptoms due to interactions between endogenous and disease-causing bacteria in other mushroom diseases, to the best of our knowledge this is the first report of an antagonistic effect.
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Affiliation(s)
- Piklu Roy Chowdhury
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
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20
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Yao Y, Xie Y, Kim KS. Genomic comparison of Escherichia coli K1 strains isolated from the cerebrospinal fluid of patients with meningitis. Infect Immun 2006; 74:2196-206. [PMID: 16552050 PMCID: PMC1418925 DOI: 10.1128/iai.74.4.2196-2206.2006] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Escherichia coli is a major cause of enteric/diarrheal diseases, urinary tract infections, and sepsis. E. coli K1 is the leading gram-negative organism causing neonatal meningitis, but the microbial basis of E. coli K1 meningitis is incompletely understood. Here we employed comparative genomic hybridization to investigate 11 strains of E. coli K1 isolated from the cerebrospinal fluid (CSF) of patients with meningitis. These 11 strains cover the majority of common O serotypes in E. coli K1 isolates from CSF. Our data demonstrated that these 11 strains of E. coli K1 can be categorized into two groups based on their profile for putative virulence factors, lipoproteins, proteases, and outer membrane proteins. Of interest, we showed that some open reading frames (ORFs) encoding the type III secretion system apparatus were found in group 2 strains but not in group 1 strains, while ORFs encoding the general secretory pathway are predominant in group 1 strains. These findings suggest that E. coli K1 strains isolated from CSF can be divided into two groups and these two groups of E. coli K1 may utilize different mechanisms to induce meningitis.
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Affiliation(s)
- Yufeng Yao
- Division of Pediatric Infectious Diseases, School of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA
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21
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Mergulhão FJM, Summers DK, Monteiro GA. Recombinant protein secretion in Escherichia coli. Biotechnol Adv 2005; 23:177-202. [PMID: 15763404 DOI: 10.1016/j.biotechadv.2004.11.003] [Citation(s) in RCA: 334] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2004] [Revised: 11/23/2004] [Accepted: 11/30/2004] [Indexed: 10/25/2022]
Abstract
The secretory production of recombinant proteins by the Gram-negative bacterium Escherichia coli has several advantages over intracellular production as inclusion bodies. In most cases, targeting protein to the periplasmic space or to the culture medium facilitates downstream processing, folding, and in vivo stability, enabling the production of soluble and biologically active proteins at a reduced process cost. This review presents several strategies that can be used for recombinant protein secretion in E. coli and discusses their advantages and limitations depending on the characteristics of the target protein to be produced.
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Affiliation(s)
- F J M Mergulhão
- Centro de Engenharia Biológica e Química, Instituto Superior Técnico, Av. Rovisco Pais, Lisbon 1049-001, Portugal.
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22
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Mergulhão FJM, Taipa MA, Cabral JMS, Monteiro GA. Evaluation of bottlenecks in proinsulin secretion by Escherichia coli. J Biotechnol 2004; 109:31-43. [PMID: 15063612 DOI: 10.1016/j.jbiotec.2003.10.024] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2002] [Revised: 09/08/2003] [Accepted: 10/14/2003] [Indexed: 10/26/2022]
Abstract
This work evaluates three potential bottlenecks in recombinant human proinsulin secretion by Escherichia coli: protein stability, secretion capacity and the effect of molecular size on secretion efficiency. A maximum secretion level of 7.2 mg g(-1) dry cell weight was obtained in the periplasm of E. coli JM109(DE3) host cells. This value probably represents an upper limit in the transport capacity of E. coli cells secreting ZZ-proinsulin and similar proteins with the protein A signal peptide. A selective deletion study was performed in the fusion partner and no effect of the molecular size (17-24 kDa) was detected on secretion efficiency. The protective effect against proteolysis provided by the ZZ domain was thoroughly demonstrated in the periplasm of E. coli and it was also shown that a single Z domain is able to provide the same protection level without compromising the downstream processing. The use of this shorter fusion partner enables a 1.6-fold increase in the recovery of the target protein after cleavage of the affinity handle.
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Affiliation(s)
- F J M Mergulhão
- Centro de Engenharia Biológica e Química, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
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23
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VanWagoner TM, Whitby PW, Morton DJ, Seale TW, Stull TL. Characterization of three new competence-regulated operons in Haemophilus influenzae. J Bacteriol 2004; 186:6409-21. [PMID: 15375121 PMCID: PMC516621 DOI: 10.1128/jb.186.19.6409-6421.2004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Haemophilus influenzae is one of a growing number of bacteria in which the natural ability to uptake exogenous DNA for potential genomic transformation has been recognized. To date, several operons involved in transformation in this organism have been described. These operons are characterized by a conserved 22-bp regulatory element upstream of the first gene and are induced coincident with transfer from rich to nutrient-depleted media. The previously identified operons comprised genes encoding proteins that include members of the type II secretion system and type IV pili, shown to be essential for transformation in other bacteria, and other proteins previously identified as required for transformation in H. influenzae. In the present study, three novel competence operons were identified by comparative genomics and transcriptional analysis. These operons have been further characterized by construction of null mutants and examination of the resulting transformation phenotypes. The putative protein encoded by the HI0366 gene was shown to be essential for DNA uptake, but not binding, and is homologous to a protein shown to be required for pilus biogenesis and twitching motility in Pseudomonas aeruginosa. An insertion in HI0939 abolished both DNA binding and uptake. The predicted product of this gene shares characteristics with PulJ, a pseudopilin involved in pullulanase export in Klebsiella oxytoca.
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Affiliation(s)
- Timothy M VanWagoner
- Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
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24
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Lammertyn E, Anné J. Protein secretion in Legionella pneumophilaand its relation to virulence. FEMS Microbiol Lett 2004. [DOI: 10.1111/j.1574-6968.2004.tb09767.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Desvaux M, Parham NJ, Scott-Tucker A, Henderson IR. The general secretory pathway: a general misnomer? Trends Microbiol 2004; 12:306-9. [PMID: 15223057 DOI: 10.1016/j.tim.2004.05.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The term general secretory pathway (GSP) has been usurped and misused in the literature over the past few years. The concept of GSP is discussed from an historical perspective, and the definitions of the general export pathway (GEP), the main terminal branch (MTB) of the GSP, the unified GSP nomenclature and the type II, IV and V secretion pathways are also described to show how they have fuelled the confusion. By putting the record straight and using novel findings within the field of bacterial protein secretion, we hope to bring clarity to this area of science and prevent further promulgation of incorrect terminologies.
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Affiliation(s)
- Mickaël Desvaux
- Institute for Biomedical Research, The University of Birmingham-The Medical School, Division of Immunity and Infection, Bacterial Pathogenesis and Genomics Unit, Vincent Drive, Edgbaston, Birmingham, UK B15 2TT.
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Abstract
Type IV pili are an efficient and versatile device for bacterial surface motility. They are widespread among the beta-, gamma-, and delta-proteobacteria and the cyanobacteria. Within that diversity, there is a core of conserved proteins that includes the pilin (PilA), the motors PilB and PilT, and various components of pilus biogenesis and assembly, PilC, PilD, PilM, PilN, PilO, PilP, and PilQ. Progress has been made in understanding the motor and the secretory functions. PilT is a motor protein that catalyzes pilus retraction; PilB may play a similar role in pilus extension. Type IV pili are multifunctional complexes that can act as bacterial virulence factors because pilus-based motility is used to spread pathogens over the surface of a tissue, or to build multicellular structures such as biofilms and fruiting bodies.
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Affiliation(s)
- Eric Nudleman
- Stanford University, Departments of Biochemistry and of Developmental Biology, Stanford, California 94305, USA
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Andersen C. Channel-tunnels: outer membrane components of type I secretion systems and multidrug efflux pumps of Gram-negative bacteria. Rev Physiol Biochem Pharmacol 2003; 147:122-65. [PMID: 12783268 DOI: 10.1007/s10254-003-0008-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
For translocation across the cell envelope of Gram-negative bacteria, substances have to overcome two permeability barriers, the inner and outer membrane. Channel-tunnels are outer membrane proteins, which are central to two distinct export systems: the type I secretion system exporting proteins such as toxins or proteases, and efflux pumps discharging antibiotics, dyes, or heavy metals and thus mediating drug resistance. Protein secretion is driven by an inner membrane ATP-binding cassette (ABC) transporter while drug efflux occurs via an inner membrane proton antiporter. Both inner membrane transporters are associated with a periplasmic accessory protein that recruits an outer membrane channel-tunnel to form a functional export complex. Prototypes of these export systems are the hemolysin secretion system and the AcrAB/TolC drug efflux pump of Escherichia coli, which both employ TolC as an outer membrane component. Its remarkable conduit-like structure, protruding 100 A into the periplasmic space, reveals how both systems are capable of transporting substrates across both membranes directly from the cytosol into the external environment. Proteins of the channel-tunnel family are widespread within Gram-negative bacteria. Their involvement in drug resistance and in secretion of pathogenic factors makes them an interesting system for further studies. Understanding the mechanism of the different export apparatus could help to develop new drugs, which block the efflux pumps or the secretion system.
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Affiliation(s)
- C Andersen
- Department of Biotechnology, University of Würzburg, 97074 Würzburg, Germany.
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28
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Abstract
Gram-negative bacteria characteristically are surrounded by an additional membrane layer, the outer membrane. Although outer membrane components often play important roles in the interaction of symbiotic or pathogenic bacteria with their host organisms, the major role of this membrane must usually be to serve as a permeability barrier to prevent the entry of noxious compounds and at the same time to allow the influx of nutrient molecules. This review summarizes the development in the field since our previous review (H. Nikaido and M. Vaara, Microbiol. Rev. 49:1-32, 1985) was published. With the discovery of protein channels, structural knowledge enables us to understand in molecular detail how porins, specific channels, TonB-linked receptors, and other proteins function. We are now beginning to see how the export of large proteins occurs across the outer membrane. With our knowledge of the lipopolysaccharide-phospholipid asymmetric bilayer of the outer membrane, we are finally beginning to understand how this bilayer can retard the entry of lipophilic compounds, owing to our increasing knowledge about the chemistry of lipopolysaccharide from diverse organisms and the way in which lipopolysaccharide structure is modified by environmental conditions.
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Affiliation(s)
- Hiroshi Nikaido
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202, USA.
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29
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Abstract
Gram-negative bacterial vesicle formation is a mechanism for specific secretion and transfer of a protein toxin to animals. This discovery should stimulate work on the mechanism of protein sorting into vesicles and the role of vesicles in bacterial pathogenesis.
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Affiliation(s)
- Samuel I Miller
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
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30
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Peabody CR, Chung YJ, Yen MR, Vidal-Ingigliardi D, Pugsley AP, Saier MH. Type II protein secretion and its relationship to bacterial type IV pili and archaeal flagella. Microbiology (Reading) 2003; 149:3051-3072. [PMID: 14600218 DOI: 10.1099/mic.0.26364-0] [Citation(s) in RCA: 281] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Homologues of the protein constituents of theKlebsiella pneumoniae(Klebsiella oxytoca) type II secreton (T2S), thePseudomonas aeruginosatype IV pilus/fimbrium biogenesis machinery (T4P) and theMethanococcus voltaeflagellum biogenesis machinery (Fla) have been identified. Known constituents of these systems include (1) a major prepilin (preflagellin), (2) several minor prepilins (preflagellins), (3) a prepilin (preflagellin) peptidase/methylase, (4) an ATPase, (5) a multispanning transmembrane (TM) protein, (6) an outer-membrane secretin (lacking in Fla) and (7) several functionally uncharacterized envelope proteins. Sequence and phylogenetic analyses led to the conclusion that, although many of the protein constituents are probably homologous, extensive sequence divergence during evolution clouds this homology so that a common ancestry can be established for all three types of systems for only two constituents, the ATPase and the TM protein. Sequence divergence of the individual T2S constituents has occurred at characteristic rates, apparently without shuffling of constituents between systems. The same is probably also true for the T4P and Fla systems. The family of ATPases is much larger than the family of TM proteins, and many ATPase homologues function in capacities unrelated to those considered here. Many phylogenetic clusters of the ATPases probably exhibit uniform function. Some of these have a corresponding TM protein homologue although others probably function without one. It is further shown that proteins that compose the different phylogenetic clusters in both the ATPase and the TM protein families exhibit unique structural characteristics that are of probable functional significance. The TM proteins are shown to have arisen by at least two dissimilar intragenic duplication events, one in the bacterial kingdom and one in the archaeal kingdom. The archaeal TM proteins are twice as large as the bacterial TM proteins, suggesting an oligomeric structure for the latter.
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Affiliation(s)
- Christopher R Peabody
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA
| | - Yong Joon Chung
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA
| | - Ming-Ren Yen
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA
| | - Dominique Vidal-Ingigliardi
- Unité de Génétique Moléculaire, CNRS URA 2172, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris, Cedex 15, France
| | - Anthony P Pugsley
- Unité de Génétique Moléculaire, CNRS URA 2172, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris, Cedex 15, France
| | - Milton H Saier
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA
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31
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Kirn TJ, Bose N, Taylor RK. Secretion of a soluble colonization factor by the TCP type 4 pilus biogenesis pathway in Vibrio cholerae. Mol Microbiol 2003; 49:81-92. [PMID: 12823812 DOI: 10.1046/j.1365-2958.2003.03546.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Colonization of the human small intestine by Vibrio cholerae requires the type 4 toxin co-regulated pilus (TCP). Genes encoding the structure and biogenesis functions of TCP are organized within an operon located on the Vibrio Pathogenicity Island (VPI). In an effort to elucidate the functions of proteins involved in TCP biogenesis, in frame deletions of all of the genes within the tcp operon coding for putative pilus biogenesis proteins have been constructed and the resulting mutants characterized with respect to the assembly and function of TCP. As a result of this analysis, we have identified the product of one of these genes, tcpF, as a novel secreted colonization factor. Chromosomal deletion of tcpF yields a mutant that retains in vitro phenotypes associated with the assembly of functional TCP yet is severely attenuated for colonization of the infant mouse intestine. Furthermore, we have determined that the mechanism by which TcpF is translocated across the bacterial outer membrane requires the TCP biogenesis machinery and is independent of the type II extracellular protein secretion (EPS) system. These results suggest a dual role for the TCP biogenesis apparatus in V. cholerae pathogenesis and a novel mechanism of intestinal colonization mediated by a soluble factor.
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Affiliation(s)
- Thomas J Kirn
- Dartmouth Medical School, Department of Microbiology and Immunology, Hanover, NH 03755, USA
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32
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Van Sluys MA, Monteiro-Vitorello CB, Camargo LEA, Menck CFM, Da Silva ACR, Ferro JA, Oliveira MC, Setubal JC, Kitajima JP, Simpson AJ. Comparative genomic analysis of plant-associated bacteria. ANNUAL REVIEW OF PHYTOPATHOLOGY 2002; 40:169-189. [PMID: 12147758 DOI: 10.1146/annurev.phyto.40.030402.090559] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This review deals with a comparative analysis of seven genome sequences from plant-associated bacteria. These are the genomes of Agrobacterium tumefaciens, Mesorhizobium loti, Sinorhizobium meliloti, Xanthomonas campestris pv campestris, Xanthomonas axonopodis pv citri, Xylella fastidiosa, and Ralstonia solanacearum. Genome structure and the metabolism pathways available highlight the compromise between the genome size and lifestyle. Despite the recognized importance of the type III secretion system in controlling host compatibility, its presence is not universal in all necrogenic pathogens. Hemolysins, hemagglutinins, and some adhesins, previously reported only for mammalian pathogens, are present in most organisms discussed. Different numbers and combinations of cell wall degrading enzymes and genes to overcome the oxidative burst generally induced by the plant host are characterized in these genomes. A total of 19 genes not involved in housekeeping functions were found common to all these bacteria.
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Affiliation(s)
- M A Van Sluys
- Depto de Botânica, Instituto de Biociências, Universidade de São Paulo, Brazil.
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33
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Gentschev I, Dietrich G, Goebel W. The E. coli alpha-hemolysin secretion system and its use in vaccine development. Trends Microbiol 2002; 10:39-45. [PMID: 11755084 DOI: 10.1016/s0966-842x(01)02259-4] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Many Gram-negative bacteria use a type I secretion system to translocate proteins, including pore-forming toxins, proteases, lipases and S-layer proteins, across both the inner and outer membranes into the extracellular surroundings. The Escherichia coli alpha-hemolysin (HlyA) secretion system is the prototypical and best characterized type I secretion system. The structure and function of the components of the HlyA secretion apparatus, HlyB, HlyD and TolC, have been studied in great detail. The functional characteristics of this secretion system enable it to be used in a variety of different applications, including the presentation of heterologous antigens in live-attenuated bacterial vaccines. Such vaccines can be an effective delivery system for heterologous antigens, and the use of a type I secretion system allows the antigens to be actively exported from the cytoplasm of the bacterial carrier rather than only becoming accessible to the host immune system after bacterial disintegration.
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Affiliation(s)
- Ivaylo Gentschev
- Department of Microbiology, University of Würzburg, D-97074 Würzburg, Germany.
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Abstract
Like a variety of other pathogenic bacteria, Aeromonas hydrophila secretes a pore-forming toxin that contribute to its virulence. The last decade has not only increased our knowledge about the structure of this toxin, called aerolysin, but has also shed light on how it interacts with its target cell and how the cell reacts to this stress. Whereas pore-forming toxins are generally thought to lead to brutal death by osmotic lysis of the cell, based on what is observed for erythrocytes, recent studies have started to reveal far more complicated pathways leading to death of nucleated mammalian cells.
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Affiliation(s)
- M Fivaz
- Department of Biochemistry, Faculty of Sciences, University of Geneva, 30 quai E. Ansermet, 1211 Geneva 4, Switzerland
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35
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Schmidt SA, Bieber D, Ramer SW, Hwang J, Wu CY, Schoolnik G. Structure-function analysis of BfpB, a secretin-like protein encoded by the bundle-forming-pilus operon of enteropathogenic Escherichia coli. J Bacteriol 2001; 183:4848-59. [PMID: 11466288 PMCID: PMC99539 DOI: 10.1128/jb.183.16.4848-4859.2001] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Production of type IV bundle-forming pili by enteropathogenic Escherichia coli (EPEC) requires BfpB, an outer-membrane lipoprotein and member of the secretin protein superfamily. BfpB was found to compose a ring-shaped, high-molecular-weight outer-membrane complex that is stable in 4% sodium dodecyl sulfate at temperatures of < or = 65 degrees C. Chemical cross-linking and immunoprecipitation experiments disclosed that the BfpB multimeric complex interacts with BfpG, and mutational studies showed that BfpG is required for the formation and/or stability of the multimer but not for the outer-membrane localization of BfpB. Formation of the BfpB multimer also does not require BfpA, the repeating subunit of the pilus filament. Functional studies of the BfpB-BfpG complex revealed that its presence confers vancomycin sensitivity, indicating that it may form an incompletely gated channel through the outer membrane. BfpB expression is also associated with accumulation of EPEC proteins in growth medium, suggesting that it may support both pilus biogenesis and protein secretion.
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Affiliation(s)
- S A Schmidt
- Departments of Medicine (Infectious Diseases and Geographic Medicine) and Microbiology & Immunology, Stanford Medical School, Stanford, California 94305, USA
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36
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Affiliation(s)
- V T Lee
- Department of Microbiology & Immunology, UCLA School of Medicine, Los Angeles, California 90095, USA.
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37
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Fivaz M, Abrami L, Tsitrin Y, van der Goot FG. Aerolysin from Aeromonas hydrophila and related toxins. Curr Top Microbiol Immunol 2001; 257:35-52. [PMID: 11417121 DOI: 10.1007/978-3-642-56508-3_3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- M Fivaz
- Department of Biochemistry, Faculty of Sciences, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
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38
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Affiliation(s)
- M Sandkvist
- Jerome H. Holland Laboratory, Department of Biochemistry, American Red Cross, Rockville, Maryland 20855, USA.
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39
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Rossier O, Cianciotto NP. Type II protein secretion is a subset of the PilD-dependent processes that facilitate intracellular infection by Legionella pneumophila. Infect Immun 2001; 69:2092-8. [PMID: 11254562 PMCID: PMC98134 DOI: 10.1128/iai.69.4.2092-2098.2001] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previously, we had demonstrated that a Legionella pneumophila prepilin peptidase (pilD) mutant does not produce type IV pili and shows reduced secretion of enzymatic activities. Moreover, it displays a distinct colony morphology and a dramatic reduction in intracellular growth within amoebae and macrophages, two phenotypes that are not exhibited by a pilin (pilE(L)) mutant. To determine whether these pilD-dependent defects were linked to type II secretion, we have constructed two new mutants of L. pneumophila strain 130b. Mutations were introduced into either lspDE, which encodes the type II outer membrane secretin and ATPase, or lspFGHIJK, which encodes the pseudopilins. Unlike the wild-type and pilE(L) strains, both lspDE and lspG mutants showed reduced secretion of six pilD-dependent enzymatic activities; i.e., protease, acid phosphatase, p-nitrophenol phosphorylcholine hydrolase, lipase, phospholipase A, and lysophospholipase A. However, they exhibited a colony morphology different from that of the pilD mutant, suggesting that their surfaces are distinct. The pilD, lspDE, and lspG mutants were similarly and greatly impaired for growth within Hartmannella vermiformis, indicating that the intracellular defect of the peptidase mutant in amoebae is explained by the loss of type II secretion. When assessed for infection of U937 macrophages, both lsp mutants exhibited a 10-fold reduction in intracellular multiplication and a diminished cytopathic effect. Interestingly, the pilD mutant was clearly 100-fold more defective than the type II secretion mutants in U937 cells. These results suggest the existence of a novel pilD-dependent mechanism for promoting L. pneumophila intracellular infection of human cells.
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Affiliation(s)
- O Rossier
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois 60611, USA
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40
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Abstract
The closely related bacterial pathogens Neisseria gonorrhoeae (gonococci, GC) and N. meningitidis (meningococci, MC) initiate infection at human mucosal epithelia. Colonization begins at apical epithelial surfaces with a multistep adhesion cascade, followed by invasion of the host cell, intracellular persistence, transcytosis, and exit. These activities are modulated by the interaction of a panoply of virulence factors with their cognate host cell receptors, and signals are sent from pathogen to host and host to pathogen at multiple stages of the adhesion cascade. Recent advances place us on the verge of understanding the colonization process at a molecular level of detail. In this review we describe the Neisseria virulence factors in the context of epithelial cell biology, placing special emphasis on the signaling functions of type IV pili, pilus-based twitching motility, and the Opa and Opc outermembrane adhesin/invasin proteins. We also summarize what is known about bacterial intracellular trafficking and growth. With the accelerated integration of tools from cell biology, biochemistry, biophysics, and genomics, experimentation in the next few years should bring unprecedented insights into the interactions of Neisseriae with their host.
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Affiliation(s)
- A J Merz
- Department of Molecular Microbiology & Immunology, L220, Oregon Health Sciences University, Portland, Oregon 97201-3098, USA
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41
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Abstract
Virulence factors of pathogenic bacteria (adhesins, toxins, invasins, protein secretion systems, iron uptake systems, and others) may be encoded by particular regions of the prokaryotic genome termed pathogenicity islands. Pathogenicity islands were first described in human pathogens of the species Escherichia coli, but have recently been found in the genomes of various pathogens of humans, animals, and plants. Pathogenicity islands comprise large genomic regions [10-200 kilobases (kb) in size] that are present on the genomes of pathogenic strains but absent from the genomes of nonpathogenic members of the same or related species. The finding that the G+C content of pathogenicity islands often differs from that of the rest of the genome, the presence of direct repeats at their ends, the association of pathogenicity islands with transfer RNA genes, the presence of integrase determinants and other mobility loci, and their genetic instability argue for the generation of pathogenicity islands by horizontal gene transfer, a process that is well known to contribute to microbial evolution. In this article we review these and other aspects of pathogenicity islands and discuss the concept that they represent a subclass of genomic islands. Genomic islands are present in the majority of genomes of pathogenic as well as nonpathogenic bacteria and may encode accessory functions which have been previously spread among bacterial populations.
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Affiliation(s)
- J Hacker
- Institut für Molekulare Infektionsbiologie, Universität Würzburg, D-97070 Würzburg, Germany.
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42
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Affiliation(s)
- T P Denny
- Dept of Plant Pathology, University of Georgia, Athens 30602-7274, USA.
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43
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Sandkvist M, Bagdasarian M, Howard SP. Characterization of the multimeric Eps complex required for cholera toxin secretion. Int J Med Microbiol 2000; 290:345-50. [PMID: 11111909 DOI: 10.1016/s1438-4221(00)80038-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Vibrio cholerae causes diarrheal disease through colonization of the small intestine. A critical aspect of V. cholerae pathogenesis is its ability to actively secrete cholera toxin to the extracellular environment. This occurs via the type II secretion pathway, where the toxin subunits are first transported to the periplasm through the Sec pathway. Following folding and assembly the toxin is then translocated across the outer membrane by a specialized Extracellular Protein Secretion (Eps) machinery encoded by at least 13 genes. Although the Eps proteins are believed to form a secretion apparatus that spans both membranes, cholera toxin is thought to engage this complex first in the periplasm. In order to determine the organization of the Eps apparatus and to understand the mechanism of secretion, the Eps apparatus has been dissected and three of the components, EpsE, EpsL and EpsM, have been purified and characterized. They were shown to form a stable, multiprotein complex spanning the cytoplasmic membrane.
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Affiliation(s)
- M Sandkvist
- Department of Biochemistry, American Red Cross, Rockville, MD 20855, USA.
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44
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Abstract
T-pilus biogenesis uses a conserved transmembrane nucleoprotein- and protein-transport apparatus for the transport of cyclic T-pilin subunits to the Agrobacterium cell surface. T-pilin subunits are processed from full-length VirB2 pro-pilin into a cyclized peptide, a rapid reaction that is Agrobacterium specific and can occur in the absence of Ti-plasmid genes.
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Affiliation(s)
- E M Lai
- Davis Crown Gall Group, University of California, One Shields Avenue, Davis, CA 95616, USA
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45
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Christie PJ, Vogel JP. Bacterial type IV secretion: conjugation systems adapted to deliver effector molecules to host cells. Trends Microbiol 2000; 8:354-60. [PMID: 10920394 PMCID: PMC4847720 DOI: 10.1016/s0966-842x(00)01792-3] [Citation(s) in RCA: 349] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Several bacterial pathogens utilize conjugation machines to export effector molecules during infection. Such systems are members of the type IV or 'adapted conjugation' secretion family. The prototypical type IV system is the Agrobacterium tumefaciens T-DNA transfer machine, which delivers oncogenic nucleoprotein particles to plant cells. Other pathogens, including Bordetella pertussis, Legionella pneumophila, Brucellaspp. and Helicobacter pylori, use type IV machines to export effector proteins to the extracellular milieu or the mammalian cell cytosol.
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Affiliation(s)
- P J Christie
- Dept of Microbiology and Molecular Genetics, The University of Texas-Houston Medical School, 6431 Fannin, Houston, TX 77030, USA.
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46
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Thanassi DG, Hultgren SJ. Multiple pathways allow protein secretion across the bacterial outer membrane. Curr Opin Cell Biol 2000; 12:420-30. [PMID: 10873830 DOI: 10.1016/s0955-0674(00)00111-3] [Citation(s) in RCA: 221] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Secretion of proteins across the bacterial outer membrane takes place via a variety of mechanisms from simple one-component systems to complex multicomponent pathways. Secretion pathways can be organized into evolutionarily and functionally related groups, which highlight their relationship with organelle biogenesis. Recent work is beginning to reveal the structure and function of various secretion components and the molecular mechanisms of secretion.
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Affiliation(s)
- D G Thanassi
- Department of Molecular Genetics and Microbiology, 130 Life Sciences Building, Center for Infectious Diseases, State University of New York at Stony Brook, Stony Brook, 11794-5222, USA.
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47
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Stathopoulos C, Hendrixson DR, Thanassi DG, Hultgren SJ, St Geme JW, Curtiss R. Secretion of virulence determinants by the general secretory pathway in gram-negative pathogens: an evolving story. Microbes Infect 2000; 2:1061-72. [PMID: 10967286 DOI: 10.1016/s1286-4579(00)01260-0] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Secretion of proteins by the general secretory pathway (GSP) is a two-step process requiring the Sec translocase in the inner membrane and a separate substrate-specific secretion apparatus for translocation across the outer membrane. Gram-negative bacteria with pathogenic potential use the GSP to deliver virulence factors into the extracellular environment for interaction with the host. Well-studied examples of virulence determinants using the GSP for secretion include extracellular toxins, pili, curli, autotransporters, and crystaline S-layers. This article reviews our current understanding of the GSP and discusses examples of terminal branches of the GSP which are utilized by factors implicated in bacterial virulence.
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Affiliation(s)
- C Stathopoulos
- Department of Biology, Washington University, One Brookings Drive, St. Louis, MO 63110, USA
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48
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Eichler J. Archaeal protein translocation crossing membranes in the third domain of life. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:3402-12. [PMID: 10848955 DOI: 10.1046/j.1432-1327.2000.01396.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Proper cell function relies on correct protein localization. As a first step in the delivery of extracytoplasmic proteins to their ultimate destinations, the hydrophobic barrier presented by lipid-based membranes must be overcome. In contrast to the well-defined bacterial and eukaryotic protein translocation systems, little is known about how proteins cross the membranes of archaea, the third and most recently described domain of life. In bacteria and eukaryotes, protein translocation occurs at proteinaceous sites comprised of evolutionarily conserved core components acting in concert with other, domain-specific elements. Examination of available archaeal genomes as well as cloning of individual genes from other archaeal strains reveals the presence of homologues to selected elements of the bacterial or eukaryotic translocation machines. Archaeal genomic searches, however, also reveal an apparent absence of other, important components of these two systems. Archaeal translocation may therefore represent a hybrid of the bacterial and eukaryotic models yet may also rely on components or themes particular to this domain of life. Indeed, considering the unique chemical composition of the archaeal membrane as well as the extreme conditions in which archaea thrive, the involvement of archaeal-specific translocation elements could be expected. Thus, understanding archaeal protein translocation could reveal the universal nature of certain features of protein translocation which, in some cases, may not be readily obvious from current comparisons of bacterial and eukaryotic systems. Alternatively, elucidation of archaeal translocation could uncover facets of the translocation process either not yet identified in bacteria or eukaryotes, or which are unique to archaea. In the following, the current status of our understanding of protein translocation in archaea is reviewed.
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Affiliation(s)
- J Eichler
- Department of Life Sciences, Ben Gurion University, Beersheva, Israel.
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49
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Hoppert M, Mayer F. Principles of macromolecular organization and cell function in bacteria and archaea. Cell Biochem Biophys 2000; 31:247-84. [PMID: 10736750 DOI: 10.1007/bf02738242] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Structural organization of the cytoplasm by compartmentation is a well established fact for the eukaryotic cell. In prokaryotes, compartmentation is less obvious. Most prokaryotes do not need intracytoplasmic membranes to maintain their vital functions. This review, especially dealing with prokaryotes, will point out that compartmentation in prokaryotes is present, but not only achieved by membranes. Besides membranes, the nucleoid, multienzyme complexes and metabolons, storage granules, and cytoskeletal elements are involved in compartmentation. In this respect, the organization of the cytoplasm of prokaryotes is similar to that in the eukaryotic cell. Compartmentation influences properties of water in cells.
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Affiliation(s)
- M Hoppert
- Abteilung Strukfurelle Mikrobiologie, Georg-August-Universitat, Göttingen, Germany.
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50
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Ray SK, Rajeshwari R, Sonti RV. Mutants of Xanthomonas oryzae pv. oryzae deficient in general secretory pathway are virulence deficient and unable to secrete xylanase. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2000; 13:394-401. [PMID: 10755302 DOI: 10.1094/mpmi.2000.13.4.394] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial leaf blight, a serious disease of rice. A virulence- and xylanase-deficient mutant of Xoo was isolated following ethyl methane sulfonate (EMS) mutagenesis. A cosmid clone that restored virulence and xylanase secretion was obtained from a genomic library by functional complementation. Transposon mutagenesis and marker exchange studies revealed genes on the cloned DNA that were required for xylanase production and virulence. Sequence analysis with transposon-specific primers revealed that these genes were homologues of xps F and xps D, which encode components of a protein secretion system in Xanthomonas campestris pv. campestris. Enzyme assays showed xylanase accumulation in the periplasmic space and cytoplasm of the xps F mutant and the complementing clone restored transport to the extracellular space.
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Affiliation(s)
- S K Ray
- Centre for Cellular and Molecular Biology, Hyderabad, India
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