Skip to main page content

• HOME
• Current Issue
• Archive
• Alerts
• About ASM
• Contact us
• Tech Support
• Journals.ASM.org

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wilharm, G. Articles by Trülzsch, K. Search for Related Content PubMed PubMed Citation Articles by Wilharm, G. Articles by Trülzsch, K.

 Previous Article  |  Next Article 

Infection and Immunity, July 2004, p. 4004-4009, Vol. 72, No. 7
0019-9567/04/$08.00+0     DOI: 10.1128/IAI.72.7.4004-4009.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

Yersinia enterocolitica Type III Secretion Depends on the Proton Motive Force but Not on the Flagellar Motor Components MotA and MotB

Gottfried Wilharm,^* Verena Lehmann, Kristina Krauss, Beatrix Lehnert, Susanna Richter, Klaus Ruckdeschel, Jürgen Heesemann, and Konrad Trülzsch

Max von Pettenkofer-Institut, D-80336 Munich, Germany

Received 2 December 2003/ Returned for modification 6 January 2004/ Accepted 15 March 2004

Top Abstract Introduction Materials and Methods Results Discussion References

 
The flagellum is believed to be the common ancestor of all type III secretion systems (TTSSs). In Yersinia enterocolitica, expression of the flagellar TTSS and the Ysc (Yop secretion) TTSS are inversely regulated. We therefore hypothesized that the Ysc TTSS may adopt flagellar motor components in order to use the pathogenicity-related translocon in a drill-like manner. As a prerequisite for this hypothesis, we first tested a requirement for the proton motive force by both systems using the protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP). Motility as well as type III-dependent secretion of Yop proteins was inhibited by CCCP. We deleted motAB, which resulted in an immotile phenotype. This mutant, however, secreted amounts of Yops to the supernatant comparable to those of the wild type. Translocation of Yops into host cells was also not affected by the motAB deletion. Virulence of the mutant was comparable to that of the wild type in the mouse oral infection model. Thus, the hypothesis that the Ysc TTSS might adopt flagellar motor components was not confirmed. The finding that, in addition to consumption of ATP, Ysc TTSS requires the proton motive force is discussed.

Top Abstract Introduction Materials and Methods Results Discussion References

 
The plasmid-encoded type III secretion system (TTSS) of pathogenic Yersinia species is used to inject antihost effector proteins, called Yops (Yersinia outer proteins), into the cytosol of susceptible eukaryotic host cells such as macrophages. Deployment of Yops by this so-called injectisome severely disrupts cellular signalling pathways and cytoskeleton structures and this disruption leads to paralysis of the attacked cells (reviewed in references 1, 5, and 6).

Virulence-associated TTSSs have been identified in several gram-negative bacteria, but the most widely distributed TTSS is the bacterial flagellum, which is believed to be the common ancestor of all TTSSs. Accordingly, many of the TTSS structural components are conserved (18).

Among the best-conserved elements of TTSSs are their putative energizers, which share some degree of homology to and ß subunits of the F₁ component of bacterial F₀F₁ proton-translocating ATPases (18). The 48-kDa protein YscN has been identified as a possible energizer of the Yersinia TTSS (31). It harbors two consensus nucleotide-binding motifs, the so-called Walker boxes A and B (30). Deletion of box A has been shown to completely abolish secretion of Yops (31). However, how YscN ATPase activity is linked to the transport of Yops remains elusive.

Secretion of flagellar components required for assembly of the flagellum is believed to be driven by the ATPase FliI, a homologue of YscN. The flagellar motor, driven by the proton motive force (PMF), enables rotation of the flagellum. The motor consists of eight stators integrated into the inner membrane, each built of four MotA and two MotB subunits. Proton flow through stators is transduced into torque generated between the cytoplasmic domains of MotA and FliG, which is attached to the membrane-embedded ring of the flagellar basal body (reviewed in reference 3). Interestingly, flagellum synthesis and motility and the Ysc (Yop secretion) TTSS in Yersinia spp. are regulated inversely in a temperature-sensitive manner (21). Yersinia enterocolitica is motile at 28°C but immotile at 37°C under in vitro growth conditions due to shut down of flagellum synthesis. On the other hand, the virulence-plasmid encoded TTSS is shut down at 28°C and requires 37°C for expression. Actually, this inverse regulation is coordinated, as has recently been evidenced. Bleves et al. (4) have demonstrated that the yop regulon was up-regulated when the flagellum master operon was deleted. These investigators speculated that the exclusive expression of just one TTSS either circumvents interference of the homologous systems or could be explained by the usage of common components. In fact, there is evidence for the interchangeability of components among the different TTSSs (2, 9, 10, 12, 27, 32, 33), which supports the idea that simultaneous functioning of two TTSS systems could lead to interference. On the other hand, recent work from DeBord et al. (8) shows that the ttsA gene of Y. enterocolitica, encoding a membrane protein, is required for both Yop secretion and motility. This finding may support the assumption that exclusive expression of TTSSs is required to allow usage of common components.

We found it tempting to speculate that pathogenic bacteria might rotate injectisomes like a drill in order to penetrate the host cell envelope and facilitate Yop delivery. In addition, rotation of a helically assembled needle may also assist the movement of transport substrates through the channel. However, MotA/MotB homologues associated with TTSSs of pathogens have not been identified. Thus, we hypothesize that exclusive expression of either flagella or the Ysc TTSS in Y. enterocolitica may be due to the requirement of flagellar motor components by the injectisome. To test this hypothesis, we deleted motAB in Y. enterocolitica and characterized the mutant.

Top Abstract Introduction Materials and Methods Results Discussion References

 
Materials. The protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) and the sodium motive force (SMF) inhibitors 2-n-heptyl-4-hydroxyquinoline N-oxide (HQNO) and phenamil were purchased from Sigma. Ingredients for Luria-Bertani (LB) and brain heart infusion (BHI) media were purchased from Difco.

Nucleic acid manipulations. An isogenic motAB mutant of Y. enterocolitica WA-314 (15) was constructed by the novel phage lambda Red recombinase cloning procedure (7). The entire coding regions of the motA and motB genes were replaced by a kanamycin resistance cassette. This was achieved by homologous recombination mediated by phage Red and Redß recombinases, which were expressed in Yersinia from a curable plasmid pKD46. For recombination, a PCR product harboring a kanamycin cassette with 50-nucleotide-homology arms was amplified from plasmid pACYC177 (New England Biolabs) with the following primers: MotABfor 5'-GGGTGCTAACGCCTCACCTTCCACCCACACACTTTGCTAAGGATATCGCGTCACTGACACCCTCATCAGTG-3', and MotABrev 5'-GGCCGCAAAGCTTTCAGTCGCGGGTCTGATTCAATTAATTGATCCAGTTTCGTCAAGTCAGCGTAATGCTC-3'.

Transformation of this PCR product into the wild type resulted in WA-314motAB, which was verified by PCR and a motility assay.

For complementation of WA-314motAB, a 2.2-kb fragment encompassing the complete motAB genes, including the putative promotor region, was amplified by PCR with primers 5'-TCTAGAGTGCTAACGCCTCACCTTCCAC-3' and 5'-GTCGACTACTGTGCGTCGCGGCTTG-3', introducing XbaI and SalI restriction sites at the ends. The PCR product was ligated into vector pGEM-T (Promega). The insert was cut out with XbaI and SalI and ligated into pACYC184 (New England Biolabs) at the same sites. The resulting plasmid, pmotAB, was transformed into WA-314motAB.

Motility assay. Motility of Y. enterocolitica WA-314 and WA-314motAB was assessed by growing strains on 0.3% floating agar (LB medium) after overnight incubation at 28°C. Optionally, agar was supplemented with CCCP (30 µM), which was added immediately before agar (45°C) was poured into petri dishes.

Analysis of secreted and translocated proteins. Yop secretion was analyzed as described previously (28). In brief, yersiniae were cultured overnight at 27°C in BHI medium. Cultures were diluted 1:40 and incubated for 2 h at 37°C in BHI medium supplemented with 200 µM CaCl₂. Then, Yop secretion was induced by Ca²⁺ depletion with 5 mM EGTA (16). Unless otherwise indicated, bacteria were pelleted (15 min, 10,000 x g) after 1.5 h of continued incubation, supernatants were precipitated with trichloroacetic acid (TCA), and precipitates were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). CCCP was freshly dissolved in dimethyl sulfoxide (DMSO) and added to the cultures as indicated for the specific experiments. DMSO was added to controls not treated with CCCP to eliminate DMSO-induced side effects. The final concentration of DMSO in cultures was usually 0.5 to 1%.

Translocation of Yops was analyzed as described previously (29). HeLa cells were infected at a multiplicity of infection of 50 for 2 h. Subsequently, cells were detached by treatment with proteinase K (30 µg/ml), which was also applied to digest extracellular Yops. HeLa cells were washed twice in phosphate-buffered saline (PBS) supplemented with 1 mM phenylmethylsulfonyl fluoride (PMSF) and lysed by osmotic shock (resuspension in distilled H₂O with 1 mM PMSF). This treatment leaves adhering bacteria intact. Cell debris was pelleted, and the supernatant was precipitated with TCA. The precipitate was subjected to SDS-PAGE, followed by Western blotting to analyze translocated Yops.

Determination of cytosolic ATP. The ATP Bioluminescence Assay kit CLS II (Roche) was used according to the manufacturer's recommendations to analyze the influence of CCCP on intracellular ATP levels. Bacterial cultures (2 ml) were centrifuged, and the pellets were resuspended in 100 mM Tris-HCl (pH 7.75)-4 mM EDTA, with adjustment of the optical density at 600 nm (OD₆₀₀) of the cell suspension to 1.0. The cell suspensions (100 µl) were boiled for 2 min at 100°C. Samples were centrifuged, and 50 µl of each supernatant was transferred to a microtiter plate that was kept on ice until measurement. Luciferase reagent (50 µl) was injected, and luminescence read with a MicroLumatPlus LB 96V luminometer (Berthold Technologies) at 20°C. ATP standards provided with the kit were diluted in the range from 10^–5 to 10^–10 M ATP.

Immunofluorescent labeling of flagella. Bacteria grown on minimal medium (M9 minimal salts, 1% glucose, 0.1% Casamino Acids, 100 µg of thiamine/ml) agar plates overnight at 28°C were gently harvested with PBS and processed for immunofluorescent staining with the use of an anti-Y. enterocolitica flagellum serum and rhodamine-conjugated secondary anti-rabbit immunoglobulin (IgG) antibodies (Sigma-Aldrich, Munich, Germany). The anti-flagellum antibody was raised against Y. enterocolitica serogroup 0:9 flagella by immunizing a New Zealand rabbit with flagella that were purified from motile bacteria by shearing through vigorous shaking. The presence of flagella in the Yersinia strains was analyzed by immunofluorescence microscopy.

Mouse infection experiments. Virulence of Y. enterocolitica WA-314 and WA-314motAB was tested in the mouse orogastric infection model as described previously (26). Prior to infection of 6- to 8-week-old C57BL/6 mice, Yersinia frozen stock suspensions (bacteria grown to late exponential phase at 27°C in LB medium) were thawed and washed twice in PBS. After appropriate dilutions, 10⁸ bacteria were fed to groups of five mice with a microliter pipette. At 5 days postinfection, mice were sacrificed and the number of bacteria surviving in the lumina of the small intestine, Peyer's patches, spleens, and livers were determined.

Top Abstract Introduction Materials and Methods Results Discussion References

 
PMF-dependence of Yop secretion. The E. coli flagellar motor is known to require the PMF (24), whereas other flagellar motors, such as that of Vibrio cholerae, are driven by SMF (14). Since Yersinia MotA and MotB exhibit high degrees of homology to Escherichia coli MotA and MotB (73 and 80% identity, respectively), it was expected that the Yersinia flagellar motor would require PMF. If MotAB engagement for Yop delivery would hold, then both motility and Yop delivery should be sensitive to the protonophore CCCP. Therefore, motility of Y. enterocolitica WA-314 was analyzed on floating agar in the absence or presence of 30 µM CCCP. As expected, motility was inhibited by CCCP at 28°C (Fig. 1A, left panel).

View larger version (12K): [in this window] [in a new window]

FIG. 1. Motility of Y. enterocolitica WA-314 (wild type [WT]) and WA-314motAB on floating agar. (A) Yersiniae were grown on 0.3% agar (LB medium) with or without 30 µM CCCP and incubated overnight at 28°C. (B) Transcomplementation of WA-314motAB with plasmid pmotAB and influence on motility.

Next, we wondered whether Yop secretion would also be sensitive to CCCP. Yersiniae were preincubated at 37°C in the presence of Ca²⁺ to induce expression of the TTSS. Then, CCCP was added (concentration range of 0, 1, 5, 10, and 15 µM) and simultaneously secretion of Yops was induced by addition of EGTA, which depletes the medium of Ca²⁺ ions (Fig. 2A). Alternatively, cultures were preincubated with CCCP for 10 min prior to induction of Yop secretion (Fig. 2B). Accumulation of Yops in the culture supernatant was analyzed by SDS-PAGE 2 h after induction of Yop secretion. As can be seen in Fig. 2A, 10 µM CCCP is sufficient to completely abolish Yop secretion immediately. In order to allow a better assessment of the specificity of this phenomenon, we analyzed the influence of CCCP on growth restriction (Fig. 3A), Yop secretion and expression (Fig. 3B), and ATP level (Fig. 3C), in parallel. Yersiniae (six cultures in parallel) were preincubated in the presence of Ca²⁺ as described above. At an OD₆₀₀ of approximately 1.0, CCCP (10 µM) was added to three cultures. DMSO, the solvent for CCCP, was added to the other three cultures at a final concentration of 0.5%. Five minutes later, secretion of Yops was induced in all six cultures by the addition of 5 mM EGTA and 10 mM MgCl₂. Before addition of CCCP-DMSO, 30 and 60 min thereafter, 2-ml aliquots of each culture were removed for analysis of the supernatant for Yop secretion and the pellet for intracellular Yops and ATP levels. Treatment with 10 µM CCCP caused an almost immediate growth arrest (Fig. 3A), accompanied by a complete inhibition of Yop secretion (Fig. 3B, upper panel). The intracellular level of Yops, as exemplified by YopE and YopH (Fig. 3B, lower panel), did not decrease dramatically with CCCP treatment. Thus, the inhibition of Yop secretion cannot be explained by a lack of secretion substrates. Since Yersinia TTSS function requires ATPase activity (31), a lack of ATP after collapse of the proton gradient could account for the abolished secretion. We therefore analyzed intracellular ATP levels by a luciferase assay (Fig. 3C). We found that the ATP levels of yersiniae treated with CCCP were comparable to those of untreated cells within an hour. Hence, CCCP treatment was not accompanied by a sudden decrease in intracellular ATP. We observed a 10 to 15% decrease in ATP levels upon CCCP treatment within minutes when CCCP was added to early- or late-logarithmic cultures (OD₆₀₀ of <0.8 or >1.4; data not shown), indicating a dependence of this reaction on the fitness of the cultures. Vigorous shaking of the cultures was also crucial for maintaining ATP levels of CCCP-treated cells comparable to ATP levels of untreated cells. Altogether, from these experiments we can conclude that Yop secretion requires PMF.

View larger version (30K): [in this window] [in a new window]

FIG. 2. Y. enterocolitica type III secretion is sensitive to the protonophore CCCP. (A) Yersiniae were grown at 37°C for 2 h. Then, secretion of Yops was started by complexing Ca2+ with EGTA; simultaneously, CCCP was added (B) Alternatively, yersiniae were grown at 37°C for 2 h, preincubated with CCCP for 10 min, and subsequently stimulated with EGTA. Secretion was analyzed after 2 h of EGTA stimulation by TCA precipitation of the culture supernatant and subsequent SDS-PAGE (Coomassie staining).

View larger version (73K): [in this window] [in a new window]

FIG. 3. Influence of CCCP on Y. enterocolitica growth (A), Yop secretion and expression (B), and ATP level (C). Six Yersinia cultures were grown in parallel for 2 h at 37°C in BHI. CCCP (10 µM) was added to three cultures, and DMSO (solvent for CCCP) was added to the other three cultures as a control. After 5 min, Yop secretion was induced by the addition of 5 mM EGTA and 10 mM MgCl2. Samples of supernatant and cell pellets were taken at 0, 30, and 60 min relative to the addition of CCCP or DMSO. The OD600 of cultures was monitored. (B) Culture samples with OD of >1 were diluted. Supernatant was precipitated with TCA, and equal amounts adjusted by OD (corresponding to approximately 1 ml of 1 OD600) were loaded onto an SDS gel and stained with Coomassie (upper panel). One fifth of corresponding cell pellets was loaded onto an SDS gel, electroblotted, and immunostained by using anti-YopE and anti-YopH antisera (lower panel). (C) For determination of intracellular ATP levels, 2 ml of bacterial cultures was centrifuged, and pellets were resuspended in 100 mM Tris-HCl (pH 7.75)-4 mM EDTA with adjustment of the OD600 of the cell suspension to 1.0. The cell suspensions (100 µl) were boiled for 2 min at 100°C. Samples were centrifuged, and 50 µl of each supernatant was transferred to a microtiter plate. Luciferase reagent (50 µl) was injected, and luminescence read by a luminometer at 20°C.

It is known that acetate can cross the membrane in its protonated form thereby acidifying the cytoplasm and accordingly reducing pH but not membrane potential . In addition, it was shown that treatment of E. coli with acetate (34 mM and pH 5) did not dramatically decrease the total PMF but reduced motility effectively (25). We found that Yop secretion was abolished upon pretreatment with 30 mM potassium acetate (pH 5.1) (data not shown). This suggests that it is the pH component of the PMF which is required for Yop secretion.

Motility and Yop secretion of Y. enterocolitica were not affected by substances that inhibit SMF driven motors (data not shown), such as HQNO and phenamil (14).

Yop secretion and mouse virulence are independent of MotAB. To test whether PMF for Yop secretion is deployed via the flagellar motor, we constructed an isogenic deletion mutant of Y. enterocolitica lacking the motor components MotA and MotB. This was accomplished by a one-step inactivation procedure based on homologous recombination between a PCR product and the target gene. Recombination by just 50-nucleotide-homology arms was made possible by expressing phage recombinases from a curable plasmid in Yersinia. Successful mutagenesis was asserted by testing motility on floating agar (Fig. 1A, right panel) and by PCR (data not shown). The motAB mutant was successfully complemented in trans by using plasmid pmotAB, a construct based on the moderate-copy-number vector pACYC184 (Fig. 1B). To ensure that the immotile phenotype was not due to a lack of flagella, caused, e.g., by interference of mutagenesis with the flagellar regulatory network, we visualized flagella. Immunofluorescence microscopy of antiserum against flagella revealed that deletion of motAB did not abolish flagellar synthesis (Fig. 4). Thus, assembly of flagella that is based on flagellar TTSS secretion does not depend on the presence of the motor components MotAB. Consistent with this finding, it has been shown that secretion of Yp1A by the Yersinia flagellar TTSS was not affected in a motA mutant (33).

View larger version (12K): [in this window] [in a new window]

FIG. 4. Immunofluorescence microscopy of yersinia (wild-type strain WA-314 left) and mutant WA-314motAB (right) flagella. Yersiniae were grown on minimal medium agar plates overnight at 28°C, gently harvested with PBS, and processed for immunofluorescent staining with anti-Y. enterocolitica flagellum serum and rhodamine-conjugated secondary anti-rabbit IgG antibodies.

Next, the influence of the motAB mutation on Yop secretion and translocation, was analyzed. Figure 5 shows that the motAB mutant secreted amounts of Yops to the culture supernatant similar to those of the wild type. The amount of intracellular Yops was also not affected (data not shown). Furthermore, no differences in cytopathic effects on infected HeLa cells or translocation of YopE and YopH into HeLa cells as determined by Western blotting of intracellular fractions could be detected (Fig. 6).

View larger version (29K): [in this window] [in a new window]

FIG. 5. Yop secretion of the Yersinia motAB mutant. Secretion of Yops by the wild-type strain and its motAB mutant was analyzed on a Coomassie-stained gel after secretion for 90 min.

View larger version (27K): [in this window] [in a new window]

FIG. 6. Translocation of Yop effectors to HeLa cells is not affected by the deletion of motAB. The translocation-deficient yscV (lcrD) mutant served as a control. HeLa cells were infected at a multiplicity of infection of 50 for 2 h. Then, cells were detached by treatment with proteinase K, washed, and lysed by osmotic shock. Samples were centrifuged. S refers to supernatant after HeLa cell lysis and subsequent TCA precipitation thus corresponding to the fraction containing translocated Yops. P refers to the pellet fraction after HeLa cell lysis including adherent bacteria and cell debris. Fractions were loaded on an SDS gel, which was electroblotted. YopE and YopH were detected with appropriate antisera.

To rule out that a possible interaction of MotAB with the injectisome could become manifest only in vivo, we orally infected C57BL/6 mice with 10⁸ CFU of the motAB mutant or the wild-type strain. Five days later, mice were sacrificed and colony counts of surviving bacteria in organs were determined. The course of infection with the mutant was progressive, with bacteria colonizing not only the small intestine and Peyer's patches but also the spleen and liver, as is the case for the wild-type strain. No significant difference in bacterial colony counts between the wild type and the mutant could be detected in Peyer's patches (5.42 ± 1.13 and 5.58 ± 0.73 mean log CFU ± standard deviations, respectively) and the spleen (6.43 ± 0.79 and 6.21 ± 1.22 mean log CFU, respectively). In summary, no evidence was found that MotAB function is linked to type III-dependent transport of Yops.

Top Abstract Introduction Materials and Methods Results Discussion References

 
In this study we examined whether the flagellar motor components MotA and MotB and the PMF play a role in protein secretion of Yops by the Y. enterocolitica TTSS. We could demonstrate that a motAB-deficient Yersinia mutant was fully virulent in the mouse orogastric infection model and competent to secrete and translocate Yops. Interestingly, additional insights can be gained from this study. Flagellum-dependent motility is essential for virulence of many pathogenic bacteria (for a review, see reference 20). However, the role that motility plays in the pathogenicity of Yersinia is less clear. The invasion capacity of an immotile Y. enterocolitica fliA mutant was shown to be unaffected in the mouse model after intragastric infection (19). Further, it was demonstrated that an immotile Y. enterocolitica flgM mutant was fully virulent according to the 50% lethal dose after intragastric inoculation (22). This finding seems reasonable since flagellar synthesis should be repressed in a 37°C host environment. However, Young et al. (34) later demonstrated in cell culture experiments that invasin-mediated invasion at 27°C requires flagellum-dependent motility to enable yersiniae to efficiently reach susceptible host cells. It is not known whether yersiniae are still motile after oral uptake by the time they have reached the M cells overlying Peyer's patches of the ileum. Therefore, it cannot be judged definitively whether motility plays a role in vivo during the infection process. However, we found no evidence for an influence of flagellum-dependent motility on dissemination of yersiniae to Peyer's patches, the spleen, and the liver, suggesting that motility is dispensable for successful infection.

The mode of energy transduction that allows type III-dependent transport of proteins is largely unexplained. Several TTSS ATPases, such as Yersinia YscN (31), have been identified, but their mode of action remains elusive.

In this study, we have shown for the first time that the Y. enterocolitica TTSS requires the PMF for secretion of Yops in addition to YscN (31). How can the PMF be used for export? The cytoplasmic side of the membrane is negatively charged relative to the periplasmic space. Accordingly, transport of negatively charged secretion substrates could be driven by the membrane potential . Since the pI of secretion substrates of the Y. enterocolitica TTSS ranges from 4.44 to 9.79, a simple electrophoretic model cannot be assumed for all secretion substrates. A dominant role of is also not supported by our finding that acetate, which decreases only pH (25), can abolish Yop secretion completely.

A recent phylogenetic analysis of P-loop NTPases by Lupas and Martin (23) in conjunction with a preceding study by Gorbalenya and Koonin (13) suggests that TTSS ATPases belong to the group of unfoldases. We therefore propose that after substrate unfolding mediated by YscN, possibly accompanied by pushing the unravelled polypeptide chain into the transport channel, additional driving force for protein export is generated by coupling to the PMF. We found that dependency of flagellar growth on the PMF was described (11 and references therein) long before the common principle of the flagellum and other TTSS machineries was identified. In addition, Galperin et al. (11) demonstrated the posttranslational assembly of flagella, recently confirmed by Hirano et al. (17). This finding supports our view that posttranslational secretion and the requirement of unfolding of TTSS substrates on the one hand and the use of PMF as a driving force on the other hand are common features of TTSSs.

 
We thank Gudrun Pfaffinger for excellent technical assistance and Gabriele Rieder for help with the luminometer.

This work was supported by the Deutsche Forschungsgemeinschaft (SFB 594 Teilprojekt B6).

 
* Corresponding author. Mailing address: Bakteriologie, Max von Pettenkofer-Institut, Pettenkoferstrasse 9a, D-80336 Munich, Germany. Phone: 49 (89) 5160 5279. Fax: 49 (89) 5160 5223. E-mail: maier{at}m3401.mpk.med.uni-muenchen.de.

Editor: J. B. Bliska

Present address: Max-Planck-Institut für Molekulare Genetik, D-14195 Berlin, Germany.

Top Abstract Introduction Materials and Methods Results Discussion References

 

1
1. Aepfelbacher, M., R. Zumbihl, K. Ruckdeschel, C. A. Jacobi, C. Barz, and J. Heesemann. 1999. The tranquilizing injection of Yersinia proteins: a pathogen's strategy to resist host defense. Biol. Chem. 380:795-802.[CrossRef][Medline]
2
2. Anderson, D. M., D. E. Fouts, A. Collmer, and O. Schneewind. 1999. Reciprocal secretion of proteins by the bacterial type III machines of plant and animal pathogens suggests universal recognition of mRNA targeting signals. Proc. Natl. Acad. Sci. USA 96:12839-12843.[Abstract/Free Full Text]
3
3. Blair, D. F. 2003. Flagellar movement driven by proton translocation. FEBS Lett. 545:86-95.[CrossRef][Medline]
4
4. Bleves, S., M. N. Marenne, G. Detry, and G. R. Cornelis. 2002. Up-regulation of the Yersinia enterocolitica yop regulon by deletion of the flagellum master operon flhDC. J. Bacteriol. 184:3214-3223.[Abstract/Free Full Text]
5
5. Cornelis, G. R. 2002. The Yersinia Ysc-Yop ‘type III’ weaponry. Nat. Rev. Mol. Cell. Biol. 3:742-752.[CrossRef][Medline]
6
6. Cornelis, G. R. 2002. The Yersinia Ysc-Yop virulence apparatus. Int. J. Med. Microbiol. 291:455-462.[CrossRef][Medline]
7
7. Datsenko, K. A., and B. L. Wanner. 2000. One-step inactivation of chromosomal genes in Escherichia coli K-12 using PCR products. Proc. Natl. Acad. Sci. USA 97:6640-6645.[Abstract/Free Full Text]
8
8. DeBord, K. L., N. S. Galanopoulos, and O. Schneewind. 2003. The ttsA gene is required for low-calcium-induced type III secretion of Yop proteins and virulence of Yersinia enterocolitica W22703. J. Bacteriol. 185:3499-3507.[Abstract/Free Full Text]
9
9. Foultier, B., P. Troisfontaines, D. Vertommen, M. N. Marenne, M. Rider, C. Parsot, and G. R. Cornelis. 2003. Identification of substrates and chaperone from the Yersinia enterocolitica 1B Ysa type III secretion system. Infect. Immun. 71:242-253.[Abstract/Free Full Text]
10
10. Frithz-Lindsten, E., Y. Du, R. Rosqvist, and A. Forsberg. 1997. Intracellular targeting of exoenzyme S of Pseudomonas aeruginosa via type III-dependent translocation induces phagocytosis resistance, cytotoxicity and disruption of actin microfilaments. Mol. Microbiol. 25:1125-1139.[CrossRef][Medline]
11
11. Galperin, M. Y., P. A. Dibrov, and A. N. Glagolev. 1982. µH+ is required for flagellar growth in Escherichia coli. FEBS Lett. 143:319-322.[CrossRef][Medline]
12
12. Ginocchio, C. C., and J. E. Galan. 1995. Functional conservation among members of the Salmonella typhimurium InvA family of proteins. Infect. Immun. 63:729-732.[Abstract]
13
13. Gorbalenya, A. E., and E. V. Koonin. 1993. Helicases: amino acid sequence comparisons and structure-function relationships. Curr. Opin. Struct. Biol. 3:419-429.
14
14. Häse, C. C., and J. J. Mekalanos. 1999. Effects of changes in membrane sodium flux on virulence gene expression in Vibrio cholerae. Proc. Natl. Acad. Sci. USA 96:3183-3187.[Abstract/Free Full Text]
15
15. Heesemann, J., B. Algermissen, and R. Laufs. 1984. Genetically manipulated virulence of Yersinia enterocolitica. Infect. Immun. 46:105-110.[Abstract/Free Full Text]
16
16. Heesemann, J., U. Gross, N. Schmidt, and R. Laufs. 1986. Immunochemical analysis of plasmid-encoded proteins released by enteropathogenic Yersinia sp. grown in calcium-deficient media. Infect. Immun. 54:561-567.[Abstract/Free Full Text]
17
17. Hirano, T., T. Minamino, K. Namba, and R. M. Macnab. 2003. Substrate specificity classes and the recognition signal for Salmonella type III flagellar export. J. Bacteriol. 185:2485-2492.[Abstract/Free Full Text]
18
18. Hueck, C. J. 1998. Type III protein secretion systems in bacterial pathogens of animals and plants. Microbiol. Mol. Biol. Rev. 62:379-433.[Abstract/Free Full Text]
19
19. Iriarte, M., I. Stainier, A. V. Mikulskis, and G. R. Cornelis. 1995. The fliA gene encoding sigma 28 in Yersinia enterocolitica. J. Bacteriol. 177:2299-2304.[Abstract/Free Full Text]
20
20. Josenhans, C., and S. Suerbaum. 2002. The role of motility as a virulence factor in bacteria. Int. J. Med. Microbiol. 291:605-614.[CrossRef][Medline]
21
21. Kapatral, V., and S. A. Minnich. 1995. Co-ordinate, temperature-sensitive regulation of the three Yersinia enterocolitica flagellin genes. Mol. Microbiol. 17:49-56.[Medline]
22
22. Kapatral, V., J. W., Olson, J. C. Pepe, V. L. Miller, and S. A. Minnich. 1996. Temperature-dependent regulation of Yersinia enterocolitica class III flagellar genes. Mol. Microbiol. 19:1061-1071.[CrossRef][Medline]
23
23. Lupas, A. N., and J. Martin. 2002. AAA proteins. Curr. Opin. Struct. Biol. 12:746-753.[CrossRef][Medline]
24
24. Manson, M. D., P. Tedesco, H. C. Berg, F. M. Harold, and C. Van der Drift. 1977. A protonmotive force drives bacterial flagella. Proc. Natl. Acad. Sci. USA 74:3060-3064.[Abstract/Free Full Text]
25
25. Minamino, T., Y. Imae, F. Oosawa, Y. Kobayashi, and K. Oosawa. 2003. Effect of intracellular pH on rotational speed of bacterial flagellar motors. J. Bacteriol. 185:1190-1194.[Abstract/Free Full Text]
26
26. Roggenkamp, A., H. R. Neuberger, A. Flugel, T. Schmoll, and J. Heesemann. 1995. Substitution of two histidine residues in YadA protein of Yersinia enterocolitica abrogates collagen binding, cell adherence and mouse virulence. Mol. Microbiol. 16:1207-1219.[Medline]
27
27. Rosqvist, R., S. Hakansson, A. Forsberg, and H. Wolf-Watz. 1995. Functional conservation of the secretion and translocation machinery for virulence proteins of yersiniae, salmonellae and shigellae. EMBO J. 14:4187-4195.[Medline]
28
28. Trek, J., G. Wilharm, C. A. Jacobi, and J. Heesemann. 2002. Yersinia enterocolitica YopQ: strain dependent cytosolic accumulation and post-translational secretion. Microbiology 148:1457-1465.[Abstract/Free Full Text]
29
29. Trülzsch, K., A. Roggenkamp, M. Aepfelbacher, G. Wilharm, K. Ruckdeschel, and J. Heesemann. 2003. Analysis of chaperone-dependent Yop secretion/translocation and effector function using a mini-virulence plasmid of Yersinia enterocolitica. Int. J. Med. Microbiol. 293:167-177.[CrossRef][Medline]
30
30. Walker, J. E., M. Saraste, M. J. Runswick, and N. J. Gay. 1982. Distantly related sequences in the alpha- and beta-subunits of ATP synthase, myosin, kinases and other ATP-requiring enzymes and a common nucleotide binding fold. EMBO J. 1:945-951.[Medline]
31
31. Woestyn, S., A. Allaoui, P. Wattiau, and G. R. Cornelis. 1994. YscN, the putative energizer of the Yersinia Yop secretion machinery. J. Bacteriol. 176:1561-1569.[Abstract/Free Full Text]
32
32. Young, B. M., and G. M. Young. 2002. Evidence for targeting of Yop effectors by the chromosomally encoded Ysa type III secretion system of Yersinia enterocolitica. J. Bacteriol. 184:5563-5571.[Abstract/Free Full Text]
33
33. Young, B. M., and G. M. Young. 2002. YplA is exported by the Ysc, Ysa, and flagellar type III secretion systems of Yersinia enterocolitica. J. Bacteriol. 184:1324-1334.[Abstract/Free Full Text]
34
34. Young, G. M., J. L. Badger, and V. L. Miller. 2000. Motility is required to initiate host cell invasion by Yersinia enterocolitica. Infect. Immun. 68:4323-4326.[Abstract/Free Full Text]

---

Infection and Immunity, July 2004, p. 4004-4009, Vol. 72, No. 7
0019-9567/04/$08.00+0     DOI: 10.1128/IAI.72.7.4004-4009.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Miki, T., Shibagaki, Y., Danbara, H., Okada, N. (2009). Functional Characterization of SsaE, a Novel Chaperone Protein of the Type III Secretion System Encoded by Salmonella Pathogenicity Island 2. J. Bacteriol. 191: 6843-6854 [Abstract] [Full Text]  
• Fowler, J. M., Wulff, C. R., Straley, S. C., Brubaker, R. R. (2009). Growth of calcium-blind mutants of Yersinia pestis at 37 {degrees}C in permissive Ca2+-deficient environments. Microbiology 155: 2509-2521 [Abstract] [Full Text]  
• Dawson, J. E., Seckute, J., De, S., Schueler, S. A., Oswald, A. B., Nicholson, L. K. (2009). Elucidation of a pH-folding switch in the Pseudomonas syringae effector protein AvrPto. Proc. Natl. Acad. Sci. USA 106: 8543-8548 [Abstract] [Full Text]  
• Schmid, A., Neumayer, W., Trulzsch, K., Israel, L., Imhof, A., Roessle, M., Sauer, G., Richter, S., Lauw, S., Eylert, E., Eisenreich, W., Heesemann, J., Wilharm, G. (2009). Cross-talk between Type Three Secretion System and Metabolism in Yersinia. J. Biol. Chem. 284: 12165-12177 [Abstract] [Full Text]  
• Lorenz, C., Buttner, D. (2009). Functional Characterization of the Type III Secretion ATPase HrcN from the Plant Pathogen Xanthomonas campestris pv. vesicatoria. J. Bacteriol. 191: 1414-1428 [Abstract] [Full Text]  
• Forbes, S. J., Eschmann, M., Mantis, N. J. (2008). Inhibition of Salmonella enterica Serovar Typhimurium Motility and Entry into Epithelial Cells by a Protective Antilipopolysaccharide Monoclonal Immunoglobulin A Antibody. Infect. Immun. 76: 4137-4144 [Abstract] [Full Text]  
• Freund, S., Czech, B., Trulzsch, K., Ackermann, N., Heesemann, J. (2008). Unusual, Virulence Plasmid-Dependent Growth Behavior of Yersinia enterocolitica in Three-Dimensional Collagen Gels. J. Bacteriol. 190: 4111-4120 [Abstract] [Full Text]  
• Schroeder, G. N., Hilbi, H. (2008). Molecular Pathogenesis of Shigella spp.: Controlling Host Cell Signaling, Invasion, and Death by Type III Secretion. Clin. Microbiol. Rev. 21: 134-156 [Abstract] [Full Text]  
• Schroeder, G. N., Jann, N. J., Hilbi, H. (2007). Intracellular type III secretion by cytoplasmic Shigella flexneri promotes caspase-1-dependent macrophage cell death. Microbiology 153: 2862-2876 [Abstract] [Full Text]  
• Hentschke, M., Trulzsch, K., Heesemann, J., Aepfelbacher, M., Ruckdeschel, K. (2007). Serogroup-Related Escape of Yersinia enterocolitica YopE from Degradation by the Ubiquitin-Proteasome Pathway. Infect. Immun. 75: 4423-4431 [Abstract] [Full Text]  
• Soscia, C., Hachani, A., Bernadac, A., Filloux, A., Bleves, S. (2007). Cross Talk between Type III Secretion and Flagellar Assembly Systems in Pseudomonas aeruginosa. J. Bacteriol. 189: 3124-3132 [Abstract] [Full Text]  
• Locher, M., Lehnert, B., Krauss, K., Heesemann, J., Groll, M., Wilharm, G. (2005). Crystal Structure of the Yersinia enterocolitica Type III Secretion Chaperone SycT. J. Biol. Chem. 280: 31149-31155 [Abstract] [Full Text]  
• Ghosh, P. (2004). Process of Protein Transport by the Type III Secretion System. Microbiol. Mol. Biol. Rev. 68: 771-795 [Abstract] [Full Text]  

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wilharm, G. Articles by Trülzsch, K. Search for Related Content PubMed PubMed Citation Articles by Wilharm, G. Articles by Trülzsch, K.