Toll-like receptors (TLRs) and the interleukin-1 receptor superfamily (IL-1Rs) are integral to both innate and adaptive immunity for host defence1,2,3. These receptors share a conserved cytoplasmic domain4,5, known as the TIR domain. A single-point mutation in the TIR domain of murine TLR4 (Pro712His, the Lpsd mutation) abolishes the host immune response to lipopolysaccharide (LPS)6, and mutation of the equivalent residue in TLR2, Pro681His, disrupts signal transduction in response to stimulation by yeast and Gram-positive bacteria7. Here we report the crystal structures of the TIR domains of human TLR1 and TLR2 and of the Pro681His mutant of TLR2. The structures have a large conserved surface patch that also contains the site of the Lpsd mutation. Mutagenesis and functional studies confirm that residues in this surface patch are crucial for receptor signalling. The Lpsd mutation does not disturb the structure of the TIR domain itself. Instead, structural and functional studies indicate that the conserved surface patch may mediate interactions with the downstream MyD88 adapter molecule7,8,9,10,11, and that the Lpsd mutation may abolish receptor signalling by disrupting this recruitment.
Access optionsAccess options
Subscribe to Journal
Get full journal access for 1 year
only $3.90 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Hoffmann, J. A., Kafatos, F. C., Janeway, C. A. Jr & Ezekowitz, R. A. B. Phylogenetic perspectives in innate immunity. Science 284, 1313–1318 (1999).
Kopp, E. B. & Medzhitov, R. The Toll-receptor family and control of innate immunity. Curr. Opin. Immunol. 11, 13–18 (1999).
Anderson, K. V. Toll signaling pathways in the innate immune response. Curr. Opin. Immunol. 12, 13–19 ( 2000).
Gay, N. J. & Keith, F. J. Drosophila Toll and IL-1 receptor. Nature 351, 355– 356 (1991).
Schneider, D. S., Hudson, K. L., Lin, T.-Y. & Anderson, K. V. Dominant and recessive mutations define functional domains of Toll, a transmembrane protein required for dorsal-ventral polarity in the Drosophila embryo. Genes Dev. 5, 797–807 ( 1991).
Poltorak, A. et al. Defective LPS signaling in C3H/HeJ and C57BL/10ScCr mice: mutations in Tlr4 gene. Science 282, 2085 –2088 (1998).
Underhill, D. M. et al. The Toll-like receptor 2 is recruited to macrophage phagosomes and discriminates between pathogens. Nature 401, 811–815 (1999).
Muzio, M., Ji, J., Feng, P. & Dixit, V. M. IRAK (Pelle) family member IRAK-2 and MyD88 as proximal mediators of IL-1 signaling. Science 278, 1612–1615 ( 1997).
Wesche, H., Henzel, W. J., Shilinglaw, W., Li, S. & Cao, Z. MyD88, an adapter that recruits IRAK to the IL-1 receptor complex. Immunity 7, 837–847 (1997).
Medzhitov, R. et al. MyD88 is an adaptor protein in the hToll/IL-1 receptor family signaling pathways. Mol. Cell 2, 253– 258 (1998).
Burns, K. et al. MyD88, an adapter protein involved in interleukin-1 signaling. J. Biol. Chem. 273, 12203– 12209 (1998).
Eck, M. J., Schoelson, S. E. & Harrison, S. C. Recognition of a high-affinity phosphotyrosyl peptide by the Src homology-2 domain of p56lck. Nature 362, 87–91 (1993).
Mitcham, J. L. et al. T1/ST2 signaling establishes it as a member of an expanding interleukin-1 receptor family. J. Biol. Chem. 271, 5777–5783 (1996).
Burns, K. et al. Tollip, a new component of the IL-1RI pathway, links IRAK to the IL-1 receptor. Nature Cell Biol. 2, 346–351 (2000).
Norris, J. L. & Manley, J. L. Selective nuclear transport of the Drosophila morphogen dorsal can be established by a signaling pathway involving the transmembrane protein Toll and protein kinase A. Genes Dev. 6, 1654–1667 (1992).
Slack, J. L. et al. Identification of two major sites in the type I interleukin-1 receptor cytoplasmic region responsible for coupling to pro-inflammatory signaling pathways. J. Biol. Chem. 275, 4670– 4678 (2000).
Huang, B., Eberstadt, M., Olejniczak, E. T., Meadows, R. P. & Fesik, S. W. NMR structure and mutagenesis of the Fas (APO-1/CD95) death domain. Nature 384, 638–641 (1996).
Shen, B. & Manley, J. L. Phosphorylation modulates direct interactions between the Toll receptor, Pelle kinase and Tube. Development 125, 4719–4728 (1998).
Du, X., Poltorak, A., Silva, M. & Beutler, B. Analysis of Tlr4-mediated LPS signal transduction in macrophages by mutational modification of the receptor. Blood Cells Mol. Dis. 25, 328– 338 (1999).
Rock, F. L., Hardiman, G., Timans, J. C., Kastelein, R. A. & Bazan, J. F. A family of human receptors structurally related to Drosophila Toll. Proc. Natl Acad. Sci. USA 95, 588–593 (1998).
Stock, J. B., Stock, A. M. & Mottonen, J. M. Signal transduction in bacteria. Nature 344, 395–400 ( 1990).
Otwinowski, Z. & Minor, W. processing of X-ray diffraction data collected in oscillation mode. Methods Enzymol. 276, 307–326 ( 1997).
Hendrickson, W. A. Determination of macromolecular structures from anomalous diffraction of synchrotron radiation. Science 254, 51– 58 (1991).
Furey, W. & Swaminathan, S. PHASES-95: A program package for processing and analyzing diffraction data from macromolecules. Methods Enzymol. 277, 590–620 (1997).
Jones, T. A., Zou, J. Y., Cowan, S. W. & Kjeldgaard, M. Improved methods for building protein models in electron density maps and the location of errors in these models. Acta Crystallogr. A 47, 110–119 (1991).
Brunger, A. et al. Crystallography & NMR System: A new software suite for macromolecular structure determination. Acta Crystallogr. D 54, 905–921 (1998).
Tong, L. Combined molecular replacement. Acta Crystallogr. A 52, 905–921 (1998).
Carson, M. Ribbon models of macromolecules. J. Mol. Graph. 5, 103–106 (1987).
Nicholls, A., Sharp, K. A. & Honig, B. Protein folding and association: insights from the interfacial and thermodynamic properties of hydrocarbons. Proteins Struct. Funct. Genet. 11, 281–296 (1991).
We thank K. D'Amico and S. Wasserman for setting up the beamline at the Advanced Photon Source (APS) (supported by the US Department of Energy), R. Abramowitz and C. Ogata for setting up the beamline at the National Synchrotron Light Source (NSLS), and the MacCHESS staff for setting up the beamline at CHESS. We thank G. Bhargava, L. Duan and G. Xu for technical help; R. Khayat, G. Jogl, and Z. Yang for help with data collection at the synchrotron sources; H. Wu and W. Hendrickson for discussions; and Columbia University (L.T.) and an NIH grant (J.L.M.) for financial support.
About this article
The metabolic regulator Lamtor5 suppresses inflammatory signaling via regulating mTOR-mediated TLR4 degradation
Cellular & Molecular Immunology (2019)
Fish & Shellfish Immunology (2019)
A toll receptor is involved in antibacterial defense in the oriental river prawn, Macrobrachium nipponense
Fish & Shellfish Immunology (2019)
Translational Oncology (2019)
Evasion of phagotrophic predation by protist hosts and innate immunity of metazoan hosts by Legionella pneumophila
Cellular Microbiology (2019)