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Ligand-induced conformational changes allosterically activate Toll-like receptor 9

A Corrigendum to this article was published on 01 November 2007

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Abstract

Microbial and synthetic DNA rich in CpG dinucleotides stimulates Toll-like receptor 9 (TLR9), whereas DNA lacking CpG either is inert or can inhibit TLR9 activation. The molecular mechanisms by which TLR9 becomes activated or is inhibited are not well understood. Here we show that TLR9 bound to stimulatory and inhibitory DNA; however, only stimulatory DNA led to substantial conformational changes in the TLR9 ectodomain. In the steady state, 'inactive' TLR9 homodimers formed in an inactivated conformation. Binding of DNA containing CpG, but not of DNA lacking CpG, to TLR9 dimers resulted in allosteric changes in the TLR9 cytoplasmic signaling domains. In endosomes, conformational changes induced by DNA containing CpG resulted in close apposition of the cytoplasmic signaling domains, a change that is probably required for the recruitment of signaling adaptor molecules. Our results indicate that the formation of TLR9 dimers is not sufficient for its activation but instead that TLR9 activation is regulated by conformational changes induced by DNA containing CpG.

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Figure 1: TLR9 binds to stimulatory and inhibitory CpG DNA.
Figure 2: Binding of DNA induces distinct conformational changes in TLR9-Fc.
Figure 3: TLR9 is expressed as a preformed homodimer.
Figure 4: Binding of ligand to TLR9 facilitates proximity-assisted folding of the 'split' GFP constructs N-GFP–TLR9 and C-GFP–TLR9 in endosomes.
Figure 5: CpG DNA leads to increased FRET efficiency between CFP-TLR9 and YFP-TLR9 in endosomes.

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Change history

  • 19 October 2007

    In the version of this article initially published, the distance values reported in Tables 1 and 2 are incorrect. The correct values are provided in the revised tables. Accordingly, line 6 on p 774 should read “7.3 nm”; line 11 on p 774 should read “a 12% decrease”; line 12 on p 777 should read “7.0 nm”; and lines 17–20 on p 777 should read “We calculated the C-terminal intermolecular distance in the endosome to be less 5.4 nm. Given the fact that the donor and acceptor fluorophores are buried inside the fluorescent proteins, their minimal distance is approximately 5.0 nm. Thus, these measurements indicate that the TLR9 TIR domains were brought in close proximity after the binding of CpG DNA ligand to the TLR9 ectodomains (Table 2).” The error has been corrected in the HTML and PDF versions of the article.

References

  1. Akira, S. & Takeda, K. Toll-like receptor signalling. Nat. Rev. Immunol. 4, 499–511 (2004).

    Article  CAS  Google Scholar 

  2. Alexopoulou, L., Holt, A.C., Medzhitov, R. & Flavell, R.A. Recognition of double-stranded RNA and activation of NF-κB by Toll-like receptor 3. Nature 413, 732–738 (2001).

    Article  CAS  Google Scholar 

  3. Heil, F. et al. Species-specific recognition of single-stranded RNA via Toll-like receptor 7 and 8. Science 303, 1526–1529 (2004).

    Article  CAS  Google Scholar 

  4. Diebold, S.S., Kaisho, T., Hemmi, H., Akira, S. & Reis e Sousa, C. Innate antiviral responses by means of TLR7-mediated recognition of single-stranded RNA. Science 303, 1529–1531 (2004).

    Article  CAS  Google Scholar 

  5. Hemmi, H. et al. A Toll-like receptor recognizes bacterial DNA. Nature 408, 740–745 (2000).

    Article  CAS  Google Scholar 

  6. Latz, E. et al. TLR9 signals after translocating from the ER to CpG DNA in the lysosome. Nat. Immunol. 5, 190–198 (2004).

    Article  CAS  Google Scholar 

  7. Krieg, A.M. et al. CpG motifs in bacterial DNA trigger direct B-cell activation. Nature 374, 546–549 (1995).

    Article  CAS  Google Scholar 

  8. Means, T.K. et al. Human lupus autoantibody-DNA complexes activate DCs through cooperation of CD32 and TLR9. J. Clin. Invest. 115, 407–417 (2005).

    Article  CAS  Google Scholar 

  9. Rifkin, I.R., Leadbetter, E.A., Busconi, L., Viglianti, G. & Marshak-Rothstein, A. Toll-like receptors, endogenous ligands, and systemic autoimmune disease. Immunol. Rev. 204, 27–42 (2005).

    Article  CAS  Google Scholar 

  10. Marshak-Rothstein, A. Toll-like receptors in systemic autoimmune disease. Nat. Rev. Immunol. 6, 823–835 (2006).

    Article  CAS  Google Scholar 

  11. Krieg, A.M. Therapeutic potential of Toll-like receptor 9 activation. Nat. Rev. Drug Discov. 5, 471–484 (2006).

    Article  CAS  Google Scholar 

  12. Agrawal, S. & Kandimalla, E.R. Medicinal chemistry and therapeutic potential of CpG DNA. Trends Mol. Med. 8, 114–121 (2002).

    Article  CAS  Google Scholar 

  13. Gay, N.J., Gangloff, M. & Weber, A.N. Toll-like receptors as molecular switches. Nat. Rev. Immunol. 6, 693–698 (2006).

    Article  CAS  Google Scholar 

  14. Yasuda, K. et al. CpG motif-independent activation of TLR9 upon endosomal translocation of “natural” phosphodiester DNA. Eur. J. Immunol. 36, 431–436 (2006).

    Article  CAS  Google Scholar 

  15. Hartmann, G. & Krieg, A.M. Mechanism and function of a newly identified CpG DNA motif in human primary B cells. J. Immunol. 164, 944–953 (2000).

    Article  CAS  Google Scholar 

  16. Ashman, R.F., Goeken, J.A., Drahos, J. & Lenert, P. Sequence requirements for oligodeoxyribonucleotide inhibitory activity. Int. Immunol. 17, 411–420 (2005).

    Article  CAS  Google Scholar 

  17. Duramad, O. et al. Inhibitors of TLR-9 act on multiple cell subsets in mouse and man in vitro and prevent death in vivo from systemic inflammation. J. Immunol. 174, 5193–5200 (2005).

    Article  CAS  Google Scholar 

  18. Barrat, F.J. et al. Nucleic acids of mammalian origin can act as endogenous ligands for Toll-like receptors and may promote systemic lupus erythematosus. J. Exp. Med. 202, 1131–1139 (2005).

    Article  CAS  Google Scholar 

  19. Kelly, S.M., Jess, T.J. & Price, N.C. How to study proteins by circular dichroism. Biochim. Biophys. Acta 1751, 119–139 (2005).

    Article  CAS  Google Scholar 

  20. Bell, J.K. et al. The molecular structure of the Toll-like receptor 3 ligand-binding domain. Proc. Natl. Acad. Sci. USA 102, 10976–10980 (2005).

    Article  CAS  Google Scholar 

  21. Choe, J., Kelker, M.S. & Wilson, I.A. Crystal structure of human Toll-like receptor 3 (TLR3) ectodomain. Science 309, 581–585 (2005).

    Article  CAS  Google Scholar 

  22. Bell, J.K. et al. Leucine-rich repeats and pathogen recognition in Toll-like receptors. Trends Immunol. 24, 528–533 (2003).

    Article  CAS  Google Scholar 

  23. Wallrabe, H. & Periasamy, A. Imaging protein molecules using FRET and FLIM microscopy. Curr. Opin. Biotechnol. 16, 19–27 (2005).

    Article  CAS  Google Scholar 

  24. Livnah, O. et al. Crystallographic evidence for preformed dimers of erythropoietin receptor before ligand activation. Science 283, 987–990 (1999).

    Article  CAS  Google Scholar 

  25. Remy, I., Wilson, I.A. & Michnick, S.W. Erythropoietin receptor activation by a ligand-induced conformation change. Science 283, 990–993 (1999).

    Article  CAS  Google Scholar 

  26. de Vos, A.M., Ultsch, M. & Kossiakoff, A.A. Human growth hormone and extracellular domain of its receptor: crystal structure of the complex. Science 255, 306–312 (1992).

    Article  CAS  Google Scholar 

  27. Tsien, R.Y. The green fluorescent protein. Annu. Rev. Biochem. 67, 509–544 (1998).

    Article  CAS  Google Scholar 

  28. Ghosh, I., Hamilton, A.D. & Regan, L. Antiparallel leucine zipper-directed protein reassembly: application to the green fluorescent protein. J. Am. Chem. Soc. 122, 5658–5659 (2000).

    Article  CAS  Google Scholar 

  29. Jeong, J. et al. Monitoring of conformational change in maltose binding protein using split green fluorescent protein. Biochem. Biophys. Res. Commun. 339, 647–651 (2006).

    Article  CAS  Google Scholar 

  30. Hacker, H. et al. Immune cell activation by bacterial CpG-DNA through myeloid differentiation marker 88 and tumor necrosis factor receptor-associated factor (TRAF)6. J. Exp. Med. 192, 595–600 (2000).

    Article  CAS  Google Scholar 

  31. Ahmad-Nejad, P. et al. Bacterial CpG-DNA and lipopolysaccharides activate Toll-like receptors at distinct cellular compartments. Eur. J. Immunol. 32, 1958–1968 (2002).

    Article  CAS  Google Scholar 

  32. Krug, A. et al. Identification of CpG oligonucleotide sequences with high induction of IFN-α/β in plasmacytoid dendritic cells. Eur. J. Immunol. 31, 2154–2163 (2001).

    Article  CAS  Google Scholar 

  33. Hartmann, G. et al. Rational design of new CpG oligonucleotides that combine B cell activation with high IFN-α induction in plasmacytoid dendritic cells. Eur. J. Immunol. 33, 1633–1641 (2003).

    Article  CAS  Google Scholar 

  34. Taylor, I.A., Davis, K.G., Watts, D. & Kneale, G.G. DNA-binding induces a major structural transition in a type I methyltransferase. EMBO J. 13, 5772–5778 (1994).

    Article  CAS  Google Scholar 

  35. Weiss, M.A. et al. Folding transition in the DNA-binding domain of GCN4 on specific binding to DNA. Nature 347, 575–578 (1990).

    Article  CAS  Google Scholar 

  36. Winkler, F.K. Structure and function of restriction endonucleases. Curr. Opin. Struct. Biol. 2, 93–99 (1992).

    Article  CAS  Google Scholar 

  37. Cheng, X., Kumar, S., Posfai, J., Pflugrath, J.W. & Roberts, R.J. Crystal structure of the HhaI DNA methyltransferase complexed with S-adenosyl-L-methionine. Cell 74, 299–307 (1993).

    Article  CAS  Google Scholar 

  38. Weber, A.N., Morse, M.A. & Gay, N.J. Four N-linked glycosylation sites in human toll-like receptor 2 cooperate to direct efficient biosynthesis and secretion. J. Biol. Chem. 279, 34589–34594 (2004).

    Article  CAS  Google Scholar 

  39. O'Neil, K.T., Hoess, R.H. & DeGrado, W.F. Design of DNA-binding peptides based on the leucine zipper motif. Science 249, 774–778 (1990).

    Article  CAS  Google Scholar 

  40. Talanian, R.V., McKnight, C.J. & Kim, P.S. Sequence-specific DNA binding by a short peptide dimer. Science 249, 769–771 (1990).

    Article  CAS  Google Scholar 

  41. Weber, A.N. et al. Binding of the Drosophila cytokine Spatzle to Toll is direct and establishes signaling. Nat. Immunol. 4, 794–800 (2003).

    Article  CAS  Google Scholar 

  42. Bell, J.K., Askins, J., Hall, P.R., Davies, D.R. & Segal, D.M. The dsRNA binding site of human Toll-like receptor 3. Proc. Natl. Acad. Sci. USA 103, 8792–8797 (2006).

    Article  CAS  Google Scholar 

  43. Jiang, Z. et al. Details of Toll-like receptor:adapter interaction revealed by germ-line mutagenesis. Proc. Natl. Acad. Sci. USA 103, 10961–10966 (2006).

    Article  CAS  Google Scholar 

  44. Hemmi, H. et al. Small anti-viral compounds activate immune cells via the TLR7 MyD88-dependent signaling pathway. Nat. Immunol. 3, 196–200 (2002).

    Article  CAS  Google Scholar 

  45. Lee, J. et al. Molecular basis for the immunostimulatory activity of guanine nucleoside analogs: activation of Toll-like receptor 7. Proc. Natl. Acad. Sci. USA 100, 6646–6651 (2003).

    Article  CAS  Google Scholar 

  46. Gorden, K.K. et al. Oligodeoxynucleotides differentially modulate activation of TLR7 and TLR8 by imidazoquinolines. J. Immunol. 177, 8164–8170 (2006).

    Article  CAS  Google Scholar 

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Acknowledgements

We thank S. Young (Leica Microsystems) and W. Becker (Becker & Hickl) for advice on FLIM measurements. Double-stranded RNA (enhanced GFP small interfering RNA duplex) was from S. Bauer (University of Marburg). Supported by the National Institutes of Health (R01AI065483 and RO1GM54060 to D.T.G and E.L.) and the Norwegian Research Council (T.E. and D.K.).

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Authors and Affiliations

Authors

Contributions

E.L., C.M.S, T.E. and D.T.G. wrote the paper; B.G.M. and A.V. cloned expression constructs; E.L., A.V., C.M.S., D.C.G.K. and M.G. did imaging and biochemical analysis; C.J.M. assisted with circular dichroism experiments; W.P.D. assisted with bimolecular fluorescence complementation experiments; M.S.L. helped with the AlphaScreen assay; and all authors discussed experimental results.

Corresponding authors

Correspondence to Eicke Latz or Douglas T Golenbock.

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The authors declare no competing financial interests.

Supplementary information

Supplementary Fig. 1

Size exclusion chromatography of TLR–Fc proteins. (PDF 268 kb)

Supplementary Fig. 2

HEK293 cells stably expressing TLR9–YFP (red), TLR9–CFP (green) alone or TLR9–CFP and TLR9–YFP (yellow) together were co-cultured on glass-bottom tissue culture dishes and analyzed by sequential scanning confocal microscopy (left). (PDF 1482 kb)

Supplementary Methods (PDF 152 kb)

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Latz, E., Verma, A., Visintin, A. et al. Ligand-induced conformational changes allosterically activate Toll-like receptor 9. Nat Immunol 8, 772–779 (2007). https://doi.org/10.1038/ni1479

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