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Zhuang XY, Lo CJ. Construction and Loss of Bacterial Flagellar Filaments. Biomolecules 2020; 10:E1528. [PMID: 33182435 PMCID: PMC7696725 DOI: 10.3390/biom10111528] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/26/2020] [Accepted: 11/04/2020] [Indexed: 11/16/2022] Open
Abstract
The bacterial flagellar filament is an extracellular tubular protein structure that acts as a propeller for bacterial swimming motility. It is connected to the membrane-anchored rotary bacterial flagellar motor through a short hook. The bacterial flagellar filament consists of approximately 20,000 flagellins and can be several micrometers long. In this article, we reviewed the experimental works and models of flagellar filament construction and the recent findings of flagellar filament ejection during the cell cycle. The length-dependent decay of flagellar filament growth data supports the injection-diffusion model. The decay of flagellar growth rate is due to reduced transportation of long-distance diffusion and jamming. However, the filament is not a permeant structure. Several bacterial species actively abandon their flagella under starvation. Flagellum is disassembled when the rod is broken, resulting in an ejection of the filament with a partial rod and hook. The inner membrane component is then diffused on the membrane before further breakdown. These new findings open a new field of bacterial macro-molecule assembly, disassembly, and signal transduction.
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Affiliation(s)
| | - Chien-Jung Lo
- Department of Physics and Graduate Institute of Biophysics, National Central University, Taoyuan City 32001, Taiwan;
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Fabiani FD, Renault TT, Peters B, Dietsche T, Gálvez EJC, Guse A, Freier K, Charpentier E, Strowig T, Franz-Wachtel M, Macek B, Wagner S, Hensel M, Erhardt M. A flagellum-specific chaperone facilitates assembly of the core type III export apparatus of the bacterial flagellum. PLoS Biol 2017; 15:e2002267. [PMID: 28771474 PMCID: PMC5542435 DOI: 10.1371/journal.pbio.2002267] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 06/30/2017] [Indexed: 11/21/2022] Open
Abstract
Many bacteria move using a complex, self-assembling nanomachine, the bacterial flagellum. Biosynthesis of the flagellum depends on a flagellar-specific type III secretion system (T3SS), a protein export machine homologous to the export machinery of the virulence-associated injectisome. Six cytoplasmic (FliH/I/J/G/M/N) and seven integral-membrane proteins (FlhA/B FliF/O/P/Q/R) form the flagellar basal body and are involved in the transport of flagellar building blocks across the inner membrane in a proton motive force-dependent manner. However, how the large, multi-component transmembrane export gate complex assembles in a coordinated manner remains enigmatic. Specific for most flagellar T3SSs is the presence of FliO, a small bitopic membrane protein with a large cytoplasmic domain. The function of FliO is unknown, but homologs of FliO are found in >80% of all flagellated bacteria. Here, we demonstrate that FliO protects FliP from proteolytic degradation and promotes the formation of a stable FliP–FliR complex required for the assembly of a functional core export apparatus. We further reveal the subcellular localization of FliO by super-resolution microscopy and show that FliO is not part of the assembled flagellar basal body. In summary, our results suggest that FliO functions as a novel, flagellar T3SS-specific chaperone, which facilitates quality control and productive assembly of the core T3SS export machinery. Many bacteria use the bacterial flagellum for directed movement in various environments. The assembly and function of the bacterial flagellum and the related virulence-associated injectisome relies on protein export via a conserved type III secretion system (T3SS). The multicomponent transmembrane core export apparatus of the flagellar T3SS consists of FlhA/B and FliP/Q/R and must assemble in a highly coordinated manner. In the present study, we determined the role of the transmembrane protein FliO in the maturation of the flagellar core protein export apparatus. We show that FliO functions as a flagellum-specific chaperone during the initial step of export apparatus assembly. FliO facilitates the efficient formation of a stable FliP–FliR core complex and is thus required for quality management and productive assembly of the flagellar export apparatus. Our results suggest a coordinated assembly process of the flagellar core export apparatus that nucleates with the FliO-dependent formation of a FliP–FliR complex. Subsequent incorporation of FliQ, FlhB, and FlhA leads to the assembly of a secretion-competent flagellar T3SS.
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Affiliation(s)
- Florian D. Fabiani
- Junior Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Thibaud T. Renault
- Junior Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Max Planck Institute for Infection Biology, Berlin, Germany
| | - Britta Peters
- Abteilung Mikrobiologie, Fachbereich Biologie/Chemie, University of Osnabrück, Osnabrück, Germany
| | - Tobias Dietsche
- Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Section of Cellular and Molecular Microbiology, University of Tübingen, Tübingen, Germany
| | - Eric J. C. Gálvez
- Junior Research Group Microbial Immune Regulation, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Alina Guse
- Junior Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Karen Freier
- Junior Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | | | - Till Strowig
- Junior Research Group Microbial Immune Regulation, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | | | - Boris Macek
- Proteome Center Tübingen, University of Tübingen, Tübingen, Germany
| | - Samuel Wagner
- Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Section of Cellular and Molecular Microbiology, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner-site Tübingen, Tübingen, Germany
| | - Michael Hensel
- Abteilung Mikrobiologie, Fachbereich Biologie/Chemie, University of Osnabrück, Osnabrück, Germany
| | - Marc Erhardt
- Junior Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, Braunschweig, Germany
- * E-mail:
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Login FH, Wolf-Watz H. YscU/FlhB of Yersinia pseudotuberculosis Harbors a C-terminal Type III Secretion Signal. J Biol Chem 2015; 290:26282-91. [PMID: 26338709 DOI: 10.1074/jbc.m114.633677] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Indexed: 12/20/2022] Open
Abstract
All type III secretion systems (T3SS) harbor a member of the YscU/FlhB family of proteins that is characterized by an auto-proteolytic process that occurs at a conserved cytoplasmic NPTH motif. We have previously demonstrated that YscUCC, the C-terminal peptide generated by auto-proteolysis of Yersinia pseudotuberculosis YscU, is secreted by the T3SS when bacteria are grown in Ca(2+)-depleted medium at 37 °C. Here, we investigated the secretion of this early T3S-substrate and showed that YscUCC encompasses a specific C-terminal T3S signal within the 15 last residues (U15). U15 promoted C-terminal secretion of reporter proteins like GST and YopE lacking its native secretion signal. Similar to the "classical" N-terminal secretion signal, U15 interacted with the ATPase YscN. Although U15 is critical for YscUCC secretion, deletion of the C-terminal secretion signal of YscUCC did neither affect Yop secretion nor Yop translocation. However, these deletions resulted in increased secretion of YscF, the needle subunit. Thus, these results suggest that YscU via its C-terminal secretion signal is involved in regulation of the YscF secretion.
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Affiliation(s)
- Frédéric H Login
- From the Department of Molecular Biology and The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, SE-901 87 Umeå, Sweden
| | - Hans Wolf-Watz
- From the Department of Molecular Biology and The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, SE-901 87 Umeå, Sweden
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Kakoschke T, Kakoschke S, Magistro G, Schubert S, Borath M, Heesemann J, Rossier O. The RNA chaperone Hfq impacts growth, metabolism and production of virulence factors in Yersinia enterocolitica. PLoS One 2014; 9:e86113. [PMID: 24454955 PMCID: PMC3893282 DOI: 10.1371/journal.pone.0086113] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 12/05/2013] [Indexed: 11/18/2022] Open
Abstract
To adapt to changes in environmental conditions, bacteria regulate their gene expression at the transcriptional but also at the post-transcriptional level, e.g. by small RNAs (sRNAs) which modulate mRNA stability and translation. The conserved RNA chaperone Hfq mediates the interaction of many sRNAs with their target mRNAs, thereby playing a global role in fine-tuning protein production. In this study, we investigated the significance of Hfq for the enteropathogen Yersina enterocolitica serotype O:8. Hfq facilitated optimal growth in complex and minimal media. Our comparative protein analysis of parental and hfq-negative strains suggested that Hfq promotes lipid metabolism and transport, cell redox homeostasis, mRNA translation and ATP synthesis, and negatively affects carbon and nitrogen metabolism, transport of siderophore and peptides and tRNA synthesis. Accordingly, biochemical tests indicated that Hfq represses ornithine decarboxylase activity, indole production and utilization of glucose, mannitol, inositol and 1,2-propanediol. Moreover, Hfq repressed production of the siderophore yersiniabactin and its outer membrane receptor FyuA. In contrast, hfq mutants exhibited reduced urease production. Finally, strains lacking hfq were more susceptible to acidic pH and oxidative stress. Unlike previous reports in other Gram-negative bacteria, Hfq was dispensable for type III secretion encoded by the virulence plasmid. Using a chromosomally encoded FLAG-tagged Hfq, we observed increased production of Hfq-FLAG in late exponential and stationary phases. Overall, Hfq has a profound effect on metabolism, resistance to stress and modulates the production of two virulence factors in Y. enterocolitica, namely urease and yersiniabactin.
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Affiliation(s)
- Tamara Kakoschke
- Max von Pettenkofer Institute for Hygiene and Medical Microbiology, Ludwig Maximilians University, Munich, Germany
| | - Sara Kakoschke
- Max von Pettenkofer Institute for Hygiene and Medical Microbiology, Ludwig Maximilians University, Munich, Germany
| | - Giuseppe Magistro
- Max von Pettenkofer Institute for Hygiene and Medical Microbiology, Ludwig Maximilians University, Munich, Germany
| | - Sören Schubert
- Max von Pettenkofer Institute for Hygiene and Medical Microbiology, Ludwig Maximilians University, Munich, Germany
| | - Marc Borath
- Protein Analysis Unit, Adolf-Butenandt Institute, Ludwig Maximilians University, Munich, Germany
| | - Jürgen Heesemann
- Max von Pettenkofer Institute for Hygiene and Medical Microbiology, Ludwig Maximilians University, Munich, Germany
| | - Ombeline Rossier
- Max von Pettenkofer Institute for Hygiene and Medical Microbiology, Ludwig Maximilians University, Munich, Germany
- * E-mail:
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Holmes TC, May AE, Zaleta-Rivera K, Ruby JG, Skewes-Cox P, Fischbach MA, DeRisi JL, Iwatsuki M, Ōmura S, Khosla C. Molecular insights into the biosynthesis of guadinomine: a type III secretion system inhibitor. J Am Chem Soc 2012; 134:17797-806. [PMID: 23030602 PMCID: PMC3483642 DOI: 10.1021/ja308622d] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Guadinomines are a recently discovered family of anti-infective compounds produced by Streptomyces sp. K01-0509 with a novel mode of action. With an IC(50) of 14 nM, guadinomine B is the most potent known inhibitor of the type III secretion system (TTSS) of Gram-negative bacteria. TTSS activity is required for the virulence of many pathogenic Gram-negative bacteria including Escherichia coli , Salmonella spp., Yersinia spp., Chlamydia spp., Vibrio spp., and Pseudomonas spp. The guadinomine (gdn) biosynthetic gene cluster has been cloned and sequenced and includes 26 open reading frames spanning 51.2 kb. It encodes a chimeric multimodular polyketide synthase, a nonribosomal peptide synthetase, along with enzymes responsible for the biosynthesis of the unusual aminomalonyl-acyl carrier protein extender unit and the signature carbamoylated cyclic guanidine. Its identity was established by targeted disruption of the gene cluster as well as by heterologous expression and analysis of key enzymes in the biosynthetic pathway. Identifying the guadinomine gene cluster provides critical insight into the biosynthesis of these scarce but potentially important natural products.
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Affiliation(s)
- Tracy C. Holmes
- Department of Chemical Engineering, Stanford University, Stanford, California 94305
| | - Aaron E. May
- Department of Chemistry, Stanford University, Stanford, California 94305
| | | | - J. Graham Ruby
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158
| | - Peter Skewes-Cox
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158
| | - Michael A. Fischbach
- Computational and Systems Biology, Cellular and Molecular Engineering, University of California, San Francisco, San Francisco, CA 94158
| | - Joseph L. DeRisi
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158
| | - Masato Iwatsuki
- Kitasato Institute for Life Sciences, Kitasato University, 5-9-1 Shirokane, Minatoku, Tokyo 108-8642, Japan
| | - Satoshi Ōmura
- Kitasato Institute for Life Sciences, Kitasato University, 5-9-1 Shirokane, Minatoku, Tokyo 108-8642, Japan
| | - Chaitan Khosla
- Department of Chemical Engineering, Stanford University, Stanford, California 94305
- Department of Chemistry, Stanford University, Stanford, California 94305
- Department of Biochemistry, Stanford University, Stanford, California 94305
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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.
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Norris V, Menu-Bouaouiche L, Becu JM, Legendre R, Norman R, Rosenzweig JA. Hyperstructure interactions influence the virulence of the type 3 secretion system in yersiniae and other bacteria. Appl Microbiol Biotechnol 2012; 96:23-36. [PMID: 22949045 DOI: 10.1007/s00253-012-4325-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 07/18/2012] [Accepted: 07/18/2012] [Indexed: 01/06/2023]
Abstract
A paradigm shift in our thinking about the intricacies of the host-parasite interaction is required that considers bacterial structures and their relationship to bacterial pathogenesis. It has been proposed that interactions between extended macromolecular assemblies, termed hyperstructures (which include multiprotein complexes), determine bacterial phenotypes. In particular, it has been proposed that hyperstructures can alter virulence. Two such hyperstructures have been characterized in both pathogenic and nonpathogenic bacteria. Present within a number of both human and plant Gram-negative pathogens is the type 3 secretion system (T3SS) injectisome which in some bacteria serves to inject toxic effector proteins directly into targeted host cells resulting in their paralysis and eventual death (but which in other bacteria prevents the death of the host). The injectisome itself comprises multiple protein subunits, which are all essential for its function. The degradosome is another multiprotein complex thought to be involved in cooperative RNA decay and processing of mRNA transcripts and has been very well characterized in nonpathogenic Escherichia coli. Recently, experimental evidence has suggested that a degradosome exists in the yersiniae as well and that its interactions within the pathogens modulate their virulence. Here, we explore the possibility that certain interactions between hyperstructures, like the T3SS and the degradosome, can ultimately influence the virulence potential of the pathogen based upon the physical locations of hyperstructures within the cell.
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Affiliation(s)
- Vic Norris
- Department of Biology, University of Rouen, 76821 Mont-Saint-Aignan, Rouen, France.
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Arnold R, Jehl A, Rattei T. Targeting effectors: the molecular recognition of Type III secreted proteins. Microbes Infect 2010; 12:346-58. [PMID: 20178857 DOI: 10.1016/j.micinf.2010.02.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2010] [Accepted: 02/10/2010] [Indexed: 01/01/2023]
Abstract
The Type III secretion system (TTSS) facilitates the export of effector proteins from pathogenic and symbiotic Gram-negative bacteria into the cytosol of eukaryotic host cells. The current functional and evolutionary knowledge on the molecular recognition of TTSS substrates and computational models of the secretion signal are discussed in this review.
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Affiliation(s)
- Roland Arnold
- Department of Genome Oriented Bioinformatics, Technische Universität München, Wissenschaftszentrum Weihenstephan, 85350 Freising, Germany
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Schmid A, Neumayer W, Trülzsch K, Israel L, Imhof A, Roessle M, Sauer G, Richter S, Lauw S, Eylert E, Eisenreich W, Heesemann J, Wilharm G. Cross-talk between type three secretion system and metabolism in Yersinia. J Biol Chem 2009; 284:12165-77. [PMID: 19244229 DOI: 10.1074/jbc.m900773200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Pathogenic yersiniae utilize a type three secretion system (T3SS) to inject Yop proteins into host cells in order to undermine their immune response. YscM1 and YscM2 proteins have been reported to be functionally equivalent regulators of the T3SS in Yersinia enterocolitica. Here, we show by affinity purification, native gel electrophoresis and small angle x-ray scattering that both YscM1 and YscM2 bind to phosphoenolpyruvate carboxylase (PEPC) of Y. enterocolitica. Under in vitro conditions, YscM1, but not YscM2, was found to inhibit PEPC with an apparent IC(50) of 4 mum (K(i) = 1 mum). To analyze the functional roles of PEPC, YscM1, and YscM2 in Yop-producing bacteria, cultures of Y. enterocolitica wild type and mutants defective in the formation of PEPC, YscM1, or YscM2, respectively, were grown under low calcium conditions in the presence of [U-(13)C(6)]glucose. The isotope compositions of secreted Yop proteins and nine amino acids from cellular proteins were analyzed by mass spectrometry. The data indicate that a considerable fraction of oxaloacetate used as precursor for amino acids was derived from [(13)C(3)]phosphoenolpyruvate by the catalytic action of PEPC in the wild-type strain but not in the PEPC(-) mutant. The data imply that PEPC is critically involved in replenishing the oxaloacetate pool in the citrate cycle under virulence conditions. In the YscM1(-) and YscM2(-) mutants, increased rates of pyruvate formation via glycolysis or the Entner-Doudoroff pathway, of oxaloacetate formation via the citrate cycle, and of amino acid biosynthesis suggest that both regulators trigger the central metabolism of Y. enterocolitica. We propose a "load-and-shoot cycle" model to account for the cross-talk between T3SS and metabolism in pathogenic yersiniae.
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Affiliation(s)
- Annika Schmid
- Department of Bacteriology, Max von Pettenkofer-Institute for Hygiene and Medical Microbiology, Pettenkoferstrasse 9a, D-80336 Munich, Germany
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Mulkidjanian AY, Makarova KS, Galperin MY, Koonin EV. Inventing the dynamo machine: the evolution of the F-type and V-type ATPases. Nat Rev Microbiol 2007; 5:892-9. [PMID: 17938630 DOI: 10.1038/nrmicro1767] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The rotary proton- and sodium-translocating ATPases are reversible molecular machines present in all cellular life forms that couple ion movement across membranes with ATP hydrolysis or synthesis. Sequence and structural comparisons of F- and V-type ATPases have revealed homology between their catalytic and membrane subunits, but not between the subunits of the central stalk that connects the catalytic and membrane components. Based on this pattern of homology, we propose that these ATPases originated from membrane protein translocases, which, themselves, evolved from RNA translocases. We suggest that in these ancestral translocases, the position of the central stalk was occupied by the translocated polymer.
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The Yersinia enterocolitica type three secretion chaperone SycO is integrated into the Yop regulatory network and binds to the Yop secretion protein YscM1. BMC Microbiol 2007; 7:67. [PMID: 17612396 PMCID: PMC1933539 DOI: 10.1186/1471-2180-7-67] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Accepted: 07/05/2007] [Indexed: 01/09/2023] Open
Abstract
Background Pathogenic yersiniae (Y. pestis, Y. pseudotuberculosis, Y. enterocolitica) share a virulence plasmid encoding a type three secretion system (T3SS). This T3SS comprises more than 40 constituents. Among these are the transport substrates called Yops (Yersinia outer proteins), the specific Yop chaperones (Sycs), and the Ysc (Yop secretion) proteins which form the transport machinery. The effectors YopO and YopP are encoded on an operon together with SycO, the chaperone of YopO. The characterization of SycO is the focus of this study. Results We have established the large-scale production of recombinant SycO in its outright form. We confirm that Y. enterocolitica SycO forms homodimers which is typical for Syc chaperones. SycO overproduction in Y. enterocolitica decreases secretion of Yops into the culture supernatant suggesting a regulatory role of SycO in type III secretion. We demonstrate that in vitro SycO interacts with YscM1, a negative regulator of Yop expression in Y. enterocolitica. However, the SycO overproduction phenotype was not mediated by YscM1, YscM2, YopO or YopP as revealed by analysis of isogenic deletion mutants. Conclusion We present evidence that SycO is integrated into the regulatory network of the Yersinia T3SS. Our picture of the Yersinia T3SS interactome is supplemented by identification of the SycO/YscM1 interaction. Further, our results suggest that at least one additional interaction partner of SycO has to be identified.
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Locher M, Lehnert B, Krauss K, Heesemann J, Groll M, Wilharm G. Crystal structure of the Yersinia enterocolitica type III secretion chaperone SycT. J Biol Chem 2005; 280:31149-55. [PMID: 16000312 DOI: 10.1074/jbc.m500603200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Several Gram-negative pathogens deploy type III secretion systems (TTSSs) as molecular syringes to inject effector proteins into host cells. Prior to secretion, some of these effectors are accompanied by specific type III secretion chaperones. The Yersinia enterocolitica TTSS chaperone SycT escorts the effector YopT, a cysteine protease that inactivates the small GTPase RhoA of targeted host cells. We solved the crystal structure of SycT at 2.5 angstroms resolution. Despite limited sequence similarity among TTSS chaperones, the SycT structure revealed a global fold similar to that exhibited by other structurally solved TTSS chaperones. The dimerization domain of SycT, however, differed from that of all other known TTSS chaperone structures. Thus, the dimerization domain of TTSS chaperones does not likely serve as a general recognition pattern for downstream processing of effector/chaperone complexes. Yersinia Yop effectors are bound to their specific Syc chaperones close to the Yop N termini, distinct from their catalytic domains. Here, we showed that the catalytically inactive YopT(C139S) is reduced in its ability to bind SycT, suggesting an ancillary interaction between YopT and SycT. This interaction could maintain the protease inactive prior to secretion or could influence the secretion competence and folding of YopT.
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Affiliation(s)
- Martin Locher
- Max-Planck-Institut für Biochemie, Am Klopferspitz 18a, D-82152 Martinsried, Germany
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