Chaperone release and unfolding of substrates in type III secretion

Abstract

Type III protein secretion systems are essential virulence factors of many bacteria pathogenic to humans, animals and plants1. These systems mediate the transfer of bacterial virulence proteins directly into the host cell cytoplasm. Proteins are thought to travel this pathway in a largely unfolded manner, and a family of customized cytoplasmic chaperones, which specifically bind cognate secreted proteins, are essential for secretion. Here we show that InvC, an ATPase associated with a Salmonella enterica type III secretion system2, has a critical function in substrate recognition. Furthermore, InvC induces chaperone release from and unfolding of the cognate secreted protein in an ATP-dependent manner. Our results show a similarity between the mechanisms of substrate recognition by type III protein secretion systems and AAA + ATPase disassembly machines.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Figure 1: The ATPase InvC interacts with TTS substrates.
Figure 2: InvC disassembles the chaperone/secreted protein complex.
Figure 3: InvC induces the unfolding of SptP.
Figure 4: Substrate unfolding is required for TTS.

References

  1. 1

    Galán, J. E. & Collmer, A. Type III secretion machines: bacterial devices for protein delivery into host cells. Science 284, 1322–1328 (1999)

    ADS  Article  Google Scholar 

  2. 2

    Eichelberg, K., Ginocchio, C. & Galán, J. E. Molecular and functional characterization of the Salmonella typhimurium invasion genes invB and invC: Homology of InvC to the FOF1 ATPase family of proteins. J. Bacteriol. 176, 4501–4510 (1994)

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  3. 3

    Cornelis, G. R. & Van Gijsegem, F. Assembly and function of type III secretory systems. Annu. Rev. Microbiol. 54, 735–774 (2000)

    CAS  Article  Google Scholar 

  4. 4

    Kubori, T. et al. Supramolecular structure of the Salmonella typhimurium type III protein secretion system. Science 280, 602–605 (1998)

    ADS  CAS  Article  Google Scholar 

  5. 5

    Marlovits, T. C. et al. Structural insights into the assembly of the type III secretion needle complex. Science 306, 1040–1042 (2004)

    ADS  CAS  Article  PubMed  PubMed Central  Google Scholar 

  6. 6

    Stebbins, C. E. & Galan, J. E. Priming virulence factors for delivery into the host. Nature Rev. Mol. Biol. 4, 738–743 (2003)

    CAS  Article  Google Scholar 

  7. 7

    Stebbins, C. E. & Galán, J. E. Maintenance of an unfolded polypeptide by a cognate chaperone in bacterial type III secretion. Nature 414, 77–81 (2001)

    ADS  CAS  Article  Google Scholar 

  8. 8

    Birtalan, S. C., Phillips, R. M. & Ghosh, P. Three-dimensional secretion signals in chaperone-effector complexes of bacterial pathogens. Mol. Cell 9, 971–980 (2002)

    CAS  Article  Google Scholar 

  9. 9

    Michiels, T. & Cornelis, G. R. Secretion of hybrid proteins by the Yersinia Yop export system. J. Bacteriol. 173, 1677–1685 (1991)

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  10. 10

    Ramamurthi, K. S. & Schneewind, O. Substrate recognition by the Yersinia type III protein secretion machinery. Mol. Microbiol. 50, 1095–1102 (2003)

    CAS  Article  PubMed  Google Scholar 

  11. 11

    Lloyd, S. A., Forsberg, A., Wolf-Watz, H. & Francis, M. S. Targeting exported substrates to the Yersinia TTSS: different functions for different signals? Trends Microbiol. 9, 367–371 (2001)

    CAS  Article  PubMed  Google Scholar 

  12. 12

    Galán, J. E. Salmonella interaction with host cells: Type III secretion at work. Annu. Rev. Cell Dev. Biol. 17, 53–86 (2001)

    Article  Google Scholar 

  13. 13

    Dreyfus, G., Williams, A. W., Kawagishi, I. & Macnab, R. M. Genetic and biochemical analysis of Salmonella typhimurium FliI, a flagellar protein related to the catalytic subunit of the FOF1 ATPase and to virulence proteins of mammalian and plant pathogens. J. Bacteriol. 175, 3131–3138 (1993)

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  14. 14

    Pozidis, C. et al. Type III protein translocase: HrcN is a peripheral ATPase that is activated by oligomerization. J. Biol. Chem. 278, 25816–25824 (2003)

    CAS  Article  PubMed  Google Scholar 

  15. 15

    Claret, L., Calder, S. R., Higgins, M. & Hughes, C. Oligomerization and activation of the FliI ATPase central to bacterial flagellum assembly. Mol. Microbiol. 48, 1349–1355 (2003)

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  16. 16

    Akeda, Y. & Galan, J. E. Genetic analysis of the Salmonella enterica type III secretion-associated ATPase InvC defines discrete functional domains. J. Bacteriol. 186, 2402–2412 (2004)

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  17. 17

    Kaniga, K., Uralil, J., Bliska, J. B. & Galán, J. E. A secreted tyrosine phosphatase with modular effector domains encoded by the bacterial pathogen Salmonella typhimurium. Mol. Microbiol. 21, 633–641 (1996)

    CAS  Article  PubMed  Google Scholar 

  18. 18

    Stebbins, C. E. & Galán, J. E. Modulation of host signalling by a bacterial mimic: structure of the Salmonella effector SptP bound to Rac1. Mol. Cell 6, 1449–1460 (2000)

    CAS  Article  Google Scholar 

  19. 19

    Gauthier, A. & Finlay, B. B. Translocated intimin receptor and its chaperone interact with ATPase of the type III secretion apparatus of enteropathogenic Escherichia coli. J. Bacteriol. 185, 6747–6755 (2003)

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  20. 20

    Luo, Y. et al. Structural and biochemical characterization of the type III secretion chaperones CesT and SigE. Nature Struct. Biol. 8, 1031–1036 (2001)

    ADS  CAS  Article  Google Scholar 

  21. 21

    Farr, G., Scharl, E., Schumacher, R., Sondek, S. & Horwich, A. Chaperonin-mediated folding in the eukaryotic cytosol proceeds through rounds of release of native and nonnative forms. Cell 89, 927–937 (1997)

    CAS  Article  PubMed  Google Scholar 

  22. 22

    Lee, S. H. & Galan, J. E. Salmonella type III secretion-associated chaperones confer secretion-pathway specificity. Mol. Microbiol. 51, 483–495 (2004)

    CAS  Article  Google Scholar 

  23. 23

    Lee, V. T. & Schneewind, O. Yop fusions to tightly folded protein domains and their effects on Yersinia enterocolitica type III secretion. J. Bacteriol. 184, 3740–3745 (2002)

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  24. 24

    Fischer, C., Schauerte, J., Wisser, K., Steel, D. & Gafni, A. Differences in the pathways for unfolding and hydrogen exchange among mutants of Escherichia coli alkaline phosphatase. Biochim. Biophys. Acta 1545, 96–103 (2001)

    CAS  Article  PubMed  Google Scholar 

  25. 25

    Sauer, R. et al. Sculpting the proteome with AAA+ proteases and disassembly machines. Cell 119, 9–18 (2004)

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  26. 26

    Ogura, T. & Wilkinson, A. AAA + superfamily ATPases: common structure—diverse function. Genes Cells 6, 575–597 (2001)

    CAS  Article  Google Scholar 

  27. 27

    Frickey, T. & Lupas, A. Phylogenetic analysis of AAA proteins. J. Struct. Biol. 146, 2–10 (2004)

    CAS  Article  PubMed  Google Scholar 

  28. 28

    Dougan, D., Mogk, A., Zeth, K., Turgay, K. & Bukau, B. AAA + proteins and substrate recognition, it all depends on their partner in crime. FEBS Lett. 529, 6–10 (2002)

    CAS  Article  PubMed  Google Scholar 

  29. 29

    Kaniga, K., Bossio, J. C. & Galán, J. E. The Salmonella typhimurium invasion genes invF and invG encode homologues to the PulD and AraC family of proteins. Mol. Microbiol. 13, 555–568 (1994)

    CAS  Article  PubMed  Google Scholar 

  30. 30

    Lara-Tejero, M. & Galán, J. E. CdtA, CdtB, and CdtC form a tripartite complex that is required for cytolethal distending toxin activity. Infect. Immun. 69, 4358–4365 (2001)

    CAS  Article  PubMed  PubMed Central  Google Scholar 

Download references

Acknowledgements

We thank A. Horwich and G. Farr for providing us with GroELD87K, S.-H. Lee for plasmid constructs, and members of the Galán laboratory for critical reading of the manuscript. This work was supported by a Public Health Service Grant.

Author information

Affiliations

Authors

Corresponding author

Correspondence to Jorge E. Galán.

Ethics declarations

Competing interests

Reprints and permissions information is available at npg.nature.com/reprintsandpermissions. The authors declare no competing financial interests.

Supplementary information

Supplementary Figure 1

Demonstrates the unfolding of SptP after addition of InvC as assayed by gel filtration and transfer to a GroEL trap mutant. (PDF 75 kb)

Supplementary Figure Legend

Text to accompany the above Supplementary Figure (DOC 20 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Akeda, Y., Galán, J. Chaperone release and unfolding of substrates in type III secretion. Nature 437, 911–915 (2005). https://doi.org/10.1038/nature03992

Download citation

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing