Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

The RickA protein of Rickettsia conorii activates the Arp2/3 complex

Abstract

Actin polymerization, the main driving force for cell locomotion, is also used by the bacteria Listeria and Shigella and vaccinia virus for intracellular and intercellular movements1,2. Seminal studies have shown the key function of the Arp2/3 complex in nucleating actin and generating a branched array of actin filaments during membrane extension and pathogen movement3. Arp2/3 requires activation by proteins such as the WASP-family proteins or ActA of Listeria. We previously reported that actin tails of Rickettsia conorii, another intracellular bacterium, unlike those of Listeria, Shigella or vaccinia, are made of long unbranched actin filaments apparently devoid of Arp2/3 (ref. 4). Here we identify a R. conorii surface protein, RickA, that activates Arp2/3 in vitro, although less efficiently than ActA. In infected cells, Arp2/3 is detected on the rickettsial surface but not in actin tails. When expressed in mammalian cells and targeted to the membrane, RickA induces filopodia. Thus RickA-induced actin polymerization, by generating long actin filaments reminiscent of those present in filopodia, has potential as a tool for studying filopodia formation.

Your institute does not have access to this article

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: The RickA protein of R. conorii activates Arp2/3.
Figure 2: Transfection with ScarWA or the C-terminal part of RickA inhibits actin polymerization.
Figure 3: Arp3 localizes with the bacteria R. conorii and with L. monocytogenes comet tails in Hep-2-infected cells.
Figure 4: Transfection of mammalian cells with RickA-CAAX induces filopodia-like structure.

References

  1. Pollard, T. D. & Borisy, G. G. Cellular motility driven by assembly and disassembly of actin filaments. Cell 112, 453–465 (2003)

    CAS  Article  Google Scholar 

  2. Frischknecht, F. & Way, M. Surfing pathogens and the lessons learned for actin polymerization. Trends Cell Biol. 11, 30–38 (2001)

    CAS  Article  Google Scholar 

  3. Welch, M. D., Rosenblatt, J., Skoble, J., Portnoy, D. A. & Mitchison, T. J. Interaction of human Arp2/3 complex and the Listeria monocytogenes ActA protein in actin filament nucleation. Science 281, 105–108 (1998)

    ADS  CAS  Article  Google Scholar 

  4. Gouin, E. et al. A comparative study of the actin-based motilities of the pathogenic bacteria Listeria monocytogenes, Shigella flexneri and Rickettsia conorii. J. Cell Sci. 112, 1697–1708 (1999)

    CAS  Google Scholar 

  5. Machesky, L. M. et al. Scar, a WASp-related protein, activates nucleation of actin filaments by the Arp2/3 complex. Proc. Natl Acad. Sci. USA 96, 3739–3744 (1999)

    ADS  CAS  Article  Google Scholar 

  6. Boujemaa-Paterski, R. et al. Listeria protein ActA mimics WASp family proteins: it activates filament barbed end branching by Arp2/3 complex. Biochemistry 40, 11390–11404 (2001)

    CAS  Article  Google Scholar 

  7. Loisel, T. P., Boujemaa, R., Pantaloni, D. & Carlier, M. F. Reconstitution of actin-based motility of Listeria and Shigella using pure proteins. Nature 401, 613–616 (1999)

    ADS  CAS  Article  Google Scholar 

  8. May, R. C. et al. The Arp2/3 complex is essential for the actin-based motility of Listeria monocytogenes. Curr. Biol. 9, 759–762 (1999)

    CAS  Article  Google Scholar 

  9. Winter, D., Lechler, T. & Li, R. Activation of the yeast Arp2/3 complex by Bee1p, a WASP-family protein. Curr. Biol. 9, 501–504 (1999)

    CAS  Article  Google Scholar 

  10. Weaver, A. M. et al. Cortactin promotes and stabilizes Arp2/3-induced actin filament network formation. Curr. Biol. 11, 370–374 (2001)

    CAS  Article  Google Scholar 

  11. Uruno, T. et al. Activation of Arp2/3 complex-mediated actin polymerization by cortactin. Nature Cell Biol. 3, 259–266 (2001)

    CAS  Article  Google Scholar 

  12. Vignjevic, D. et al. Formation of filopodia-like bundles in vitro from a dendritic network. J. Cell Biol. 160, 951–962 (2003)

    CAS  Article  Google Scholar 

  13. Hackstadt, T. The biology of Rickettsiae. Infect. Agents Dis. 5, 127–143 (1996)

    CAS  PubMed  Google Scholar 

  14. Teysseire, N., Chiche-Portiche, C. & Raoult, D. Intracellular movements of Rickettsia conorii and R. typhi based on actin polymerization. Res. Microbiol. 143, 821–829 (1992)

    CAS  Article  Google Scholar 

  15. Andersson, S. G. et al. The genome sequence of Rickettsia prowazekii and the origin of mitochondria. Nature 396, 133–140 (1998)

    ADS  CAS  Article  Google Scholar 

  16. Ogata, H. et al. Mechanisms of evolution in Rickettsia conorii and R. prowazekii. Science 293, 2093–2098 (2001)

    ADS  CAS  Article  Google Scholar 

  17. Van Troys, M. et al. The actin binding site of thymosin beta 4 mapped by mutational analysis. EMBO J. 15, 201–210 (1996)

    CAS  Article  Google Scholar 

  18. Panchal, S. C., Kaiser, D. A., Torres, E., Pollard, T. D. & Rosen, M. K. A conserved amphipathic helix in WASP/Scar proteins is essential for activation of Arp2/3 complex. Nature Struct. Biol. 10, 591–598 (2003)

    CAS  Article  Google Scholar 

  19. Blanchoin, L. et al. Direct observation of dendritic actin filament networks nucleated by Arp2/3 complex and WASP/Scar proteins. Nature 404, 1007–1011 (2000)

    ADS  CAS  Article  Google Scholar 

  20. Van Kirk, L. S., Hayes, S. F. & Heinzen, R. A. Ultrastructure of Rickettsia rickettsii actin tails and localization of cytoskeletal proteins. Infect. Immun. 68, 4706–4713 (2000)

    CAS  Article  Google Scholar 

  21. Friederich, E. et al. Targeting of Listeria monocytogenes ActA protein to the plasma membrane as a tool to dissect both actin-based cell morphogenesis and ActA function. EMBO J. 14, 2731–2744 (1995)

    CAS  Article  Google Scholar 

  22. Kureishy, N., Sapountzi, V., Prag, S., Anilkumar, N. & Adams, J. C. Fascins, and their roles in cell structure and function. Bioessays 24, 350–361 (2002)

    CAS  Article  Google Scholar 

  23. Chakraborty, T. et al. A focal adhesion factor directly linking intracellularly motile Listeria monocytogenes and Listeria ivanovii to the actin-based cytoskeleton of mammalian cells. EMBO J. 14, 1314–1321 (1995)

    CAS  Article  Google Scholar 

  24. Bear, J. E. et al. Negative regulation of fibroblast motility by Ena/VASP proteins. Cell 101, 717–728 (2000)

    CAS  Article  Google Scholar 

  25. Bear, J. E. et al. Antagonism between Ena/VASP proteins and actin filament capping regulates fibroblast motility. Cell 109, 509–521 (2002)

    CAS  Article  Google Scholar 

  26. Skoble, J. et al. Pivotal role of VASP in Arp2/3 complex-mediated actin nucleation, actin branch-formation, and Listeria monocytogenes motility. J. Cell Biol. 155, 89–100 (2001)

    CAS  Article  Google Scholar 

  27. Cory, G. O., Cramer, R., Blanchoin, L. & Ridley, A. J. Phosphorylation of the WASP-VCA domain increases its affinity for the Arp2/3 complex and enhances actin polymerization by WASP. Mol. Cell 11, 1229–1239 (2003)

    CAS  Article  Google Scholar 

  28. Lamarche, N. et al. Production of the R2 subunit of ribonucleotide reductase from herpes simplex virus with prokaryotic and eukaryotic expression systems: higher activity of R2 produced by eukaryotic cells related to higher iron-binding capacity. Biochem. J. 320, 129–135 (1996)

    CAS  Article  Google Scholar 

  29. David, V. et al. Identification of cofilin, coronin, Rac and capZ in actin tails using a Listeria affinity approach. J. Cell Sci. 111, 2877–2884 (1998)

    CAS  PubMed  Google Scholar 

Download references

Acknowledgements

We thank L. Blanchoin for help and discussions, L. Machesky for the gift of plasmids Scar-WA and ScarW, and P. Renesto and all members of the Cossart laboratory for discussions and suggestions. This work was supported by the Pasteur Institute, the Ministère de la Recherche et de la Technologie (Programme PRFMMIP) and the Direction Générale des Armées (DGA). C.E. is supported by a Human Frontier Science programme fellowship. P.C. is an international scholar from the Howard Hughes Medical Institute.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Pascale Cossart.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Supplementary information

Supplementary Figure 1: The amino acid sequences of RickA from R. conorii and ActA from L. monocytogenes. (PDF 21 kb)

41586_2004_BFnature02318_MOESM2_ESM.jpg

Supplementary Figure 2: The Rickettsia actin tails consist of long filaments. Electron microscopy of myosin S1 decorated actin tails of R. conorii and L. monocytogenes. (JPG 80 kb)

41586_2004_BFnature02318_MOESM3_ESM.jpg

Supplementary Figure 3: The rickettsia actin tails contain the bundling protein fascin. . Vero cells were infected with Rickettsia and transfected 24 hours later with a plasmid expressing GFP-fascin before processing for immunofluorescence 24 hours later, using the R47 antibody. (JPG 60 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Gouin, E., Egile, C., Dehoux, P. et al. The RickA protein of Rickettsia conorii activates the Arp2/3 complex. Nature 427, 457–461 (2004). https://doi.org/10.1038/nature02318

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature02318

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

Quick links

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