FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W2006348886> ?p ?o ?g. }

• W2006348886 endingPage "4098" @default.
• W2006348886 startingPage "4088" @default.
• W2006348886 abstract "Toll-like receptor signaling requires interactions of the Toll/IL-1 receptor (TIR) domains of the receptor and adapter proteins. Using the mammalian protein-protein interaction trap strategy, homology modeling, and site-directed mutagenesis, we identify the interaction surfaces in the TLR4 TIR domain for the TLR4-TLR4, TLR4-MyD88 adapter-like (MAL), and TLR4-TRIF-related adapter molecule (TRAM) interaction. Two binding sites are equally important for TLR4 dimerization and adapter recruitment. In a model based on the crystal structure of the dimeric TLR10 TIR domain, the first binding site mediates TLR4-TLR4 TIR-TIR interaction. Upon dimerization, two identical second binding sites of the TLR4 TIR domain are juxtaposed and form an extended binding platform for both MAL and TRAM. In our mammalian protein-protein interaction trap assay, MAL and TRAM compete for binding to this platform. Our data suggest that adapter binding can stabilize the TLR4 TIR dimerization. Toll-like receptor signaling requires interactions of the Toll/IL-1 receptor (TIR) domains of the receptor and adapter proteins. Using the mammalian protein-protein interaction trap strategy, homology modeling, and site-directed mutagenesis, we identify the interaction surfaces in the TLR4 TIR domain for the TLR4-TLR4, TLR4-MyD88 adapter-like (MAL), and TLR4-TRIF-related adapter molecule (TRAM) interaction. Two binding sites are equally important for TLR4 dimerization and adapter recruitment. In a model based on the crystal structure of the dimeric TLR10 TIR domain, the first binding site mediates TLR4-TLR4 TIR-TIR interaction. Upon dimerization, two identical second binding sites of the TLR4 TIR domain are juxtaposed and form an extended binding platform for both MAL and TRAM. In our mammalian protein-protein interaction trap assay, MAL and TRAM compete for binding to this platform. Our data suggest that adapter binding can stabilize the TLR4 TIR dimerization. IntroductionToll-like receptors (TLRs) 3The abbreviations used are: TLRToll-like receptorTIR domainToll/interleukin-1 receptor domainMALMyD88 adapter-likeTrifTIR-domain-containing adapter inducing interferon-βTRAMTRIF-related adapter moleculeMAPPITmammalian protein-protein interaction trapTricineN-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]glycineSVTSV40 large T. are pathogen recognition receptors that play a crucial role in innate immunity (1Gay N.J. Gangloff M. Structure and function of Toll receptors and their ligands.Annu. Rev. Biochem. 2007; 76: 141-165Crossref PubMed Scopus (505) Google Scholar, 2Hennessy E.J. Parker A.E. O'Neill L.A. Targeting Toll-like receptors. Emerging therapeutics.Nat. Rev. Drug Discov. 2010; 9: 293-307Crossref PubMed Scopus (630) Google Scholar, 3Kawai T. Akira S. The role of pattern-recognition receptors in innate immunity. Update on Toll-like receptors.Nat. Immunol. 2010; 11: 373-384Crossref PubMed Scopus (6025) Google Scholar). TLRs are composed of an extracellular domain with leucine-rich repeats for ligand recognition, a transmembrane helix, and a cytoplasmic part with a Toll-IL-1R (TIR) domain. Ligand-induced receptor dimerization or oligomerization leads to the recruitment of TIR domain-containing adapter proteins for downstream signaling.Lipopolysaccharide (LPS) binding to the TLR4 complex is followed by interaction with the adapter proteins MAL and TRAM. MAL and TRAM are bridging adapters that recruit the signaling adapters MyD88 and TRIF to the receptor (4Gay N.J. Gangloff M. O'Neill L.A. What the Myddosome structure tells us about the initiation of innate immunity.Trends Immunol. 2011; 32: 104-109Abstract Full Text Full Text PDF PubMed Scopus (134) Google Scholar, 5Jenkins K.A. Mansell A. TIR-containing adapters in Toll-like receptor signaling.Cytokine. 2010; 49: 237-244Crossref PubMed Scopus (99) Google Scholar, 6Kagan J.C. Medzhitov R. Phosphoinositide-mediated adapter recruitment controls Toll-like receptor signaling.Cell. 2006; 125: 943-955Abstract Full Text Full Text PDF PubMed Scopus (660) Google Scholar, 7Kagan J.C. Su T. Horng T. Chow A. Akira S. Medzhitov R. TRAM couples endocytosis of Toll-like receptor 4 to the induction of interferon-β.Nat. Immunol. 2008; 9: 361-368Crossref PubMed Scopus (931) Google Scholar, 8O'Neill L.A. Bowie A.G. The family of five. TIR-domain-containing adapters in Toll-like receptor signaling.Nat. Rev. Immunol. 2007; 7: 353-364Crossref PubMed Scopus (1968) Google Scholar).The TLR4-MAL-MyD88 complex is formed at the plasma membrane, and localization of MAL at the plasma membrane is facilitated by its phosphatidylinositol 4,5-bisphosphate binding domain (6Kagan J.C. Medzhitov R. Phosphoinositide-mediated adapter recruitment controls Toll-like receptor signaling.Cell. 2006; 125: 943-955Abstract Full Text Full Text PDF PubMed Scopus (660) Google Scholar). The MAL/MyD88 axis leads to activation of MAPKs and of transcription factors, activation protein 1 (AP-1) and NF-κB. A myristoylation site of TRAM directs this adapter protein to the membrane of early endosomes (7Kagan J.C. Su T. Horng T. Chow A. Akira S. Medzhitov R. TRAM couples endocytosis of Toll-like receptor 4 to the induction of interferon-β.Nat. Immunol. 2008; 9: 361-368Crossref PubMed Scopus (931) Google Scholar). The TLR4-TRAM-TRIF complex is formed in endosomal compartments and leads to activation of the transcription factor IRF3 and interferon production (9Lu Y.C. Yeh W.C. Ohashi P.S. LPS/TLR4 signal transduction pathway.Cytokine. 2008; 42: 145-151Crossref PubMed Scopus (1955) Google Scholar).Interactions between the TIR domains are crucial for TLR signal transduction. Both the receptor and the adapter TIR domains can dimerize or oligomerize; the receptor TIR domains interact with adapter TIR domains, and additionally, the TIR domains of MAL and TRAM interact;, respectively, with the TIR domains of MyD88 (10Fitzgerald K.A. Palsson-McDermott E.M. Bowie A.G. Jefferies C.A. Mansell A.S. Brady G. Brint E. Dunne A. Gray P. Harte M.T. McMurray D. Smith D.E. Sims J.E. Bird T.A. O'Neill L.A. Mal (MyD88-adapter-like) is required for Toll-like receptor-4 signal transduction.Nature. 2001; 413: 78-83Crossref PubMed Scopus (992) Google Scholar) and TRIF (11Fitzgerald K.A. Rowe D.C. Barnes B.J. Caffrey D.R. Visintin A. Latz E. Monks B. Pitha P.M. Golenbock D.T. LPS-TLR4 signaling to IRF-3/7 and NF-kappaB involves the toll adapters TRAM and TRIF.J. Exp. Med. 2003; 198: 1043-1055Crossref PubMed Scopus (918) Google Scholar). Although the molecular structures of the TIR domain of TLR1, TLR2, TLR10, IL-1RAPL, MAL, and MyD88 were determined (12Xu Y. Tao X. Shen B. Horng T. Medzhitov R. Manley J.L. Tong L. Structural basis for signal transduction by the Toll/interleukin-1 receptor domains.Nature. 2000; 408: 111-115Crossref PubMed Scopus (221) Google Scholar, 13Tao X. Xu Y. Zheng Y. Beg A.A. Tong L. An extensively associated dimer in the structure of the C713S mutant of the TIR domain of human TLR2.Biochem. Biophys. Res. Commun. 2002; 299: 216-221Crossref PubMed Scopus (98) Google Scholar, 14Khan J.A. Brint E.K. O'Neill L.A. Tong L. Crystal structure of the Toll/interleukin-1 receptor domain of human IL-1RAPL.J. Biol. Chem. 2004; 279: 31664-31670Abstract Full Text Full Text PDF PubMed Scopus (116) Google Scholar, 15Nyman T. Stenmark P. Flodin S. Johansson I. Hammarström M. Nordlund P. The crystal structure of the human toll-like receptor 10 cytoplasmic domain reveals a putative signaling dimer.J. Biol. Chem. 2008; 283: 11861-11865Abstract Full Text Full Text PDF PubMed Scopus (161) Google Scholar, 16Ohnishi H. Tochio H. Kato Z. Orii K.E. Li A. Kimura T. Hiroaki H. Kondo N. Shirakawa M. Structural basis for the multiple interactions of the MyD88 TIR domain in TLR4 signaling.Proc. Natl. Acad. Sci. U.S.A. 2009; 106: 10260-10265Crossref PubMed Scopus (166) Google Scholar, 17Valkov E. Stamp A. Dimaio F. Baker D. Verstak B. Roversi P. Kellie S. Sweet M.J. Mansell A. Gay N.J. Martin J.L. Kobe B. Crystal structure of Toll-like receptor adapter MAL/TIRAP reveals the molecular basis for signal transduction and disease protection.Proc. Natl. Acad. Sci. U.S.A. 2011; 108: 14879-14884Crossref PubMed Scopus (105) Google Scholar), the TIR domain interaction mechanism and the exact positions of the interaction interfaces remain unknown.The TIR domain contains a central fully parallel five-stranded β sheet (βA through βE) surrounded by five α helices (αA through αE). The β sheets and α helices are connected by loops (AA–EE). Various articles demonstrate the importance of the BB loop between the βB strand and the αB helix (18Jiang Z. Georgel P. Li C. Choe J. Crozat K. Rutschmann S. Du X. Bigby T. Mudd S. Sovath S. Wilson I.A. Olson A. Beutler B. Details of Toll-like receptor:adapter interaction revealed by germ-line mutagenesis.Proc. Natl. Acad. Sci. U.S.A. 2006; 103: 10961-10966Crossref PubMed Scopus (109) Google Scholar). A P712H mutation in the BB loop of TLR4 in C3H/HeJ mice leads to complete unresponsiveness to LPS (19Poltorak A. He X. Smirnova I. Liu M.Y. Van Huffel C. Du X. Birdwell D. Alejos E. Silva M. Galanos C. Freudenberg M. Ricciardi-Castagnoli P. Layton B. Beutler B. Defective LPS signaling in C3H/HeJ and C57BL/10ScCr mice. Mutations in Tlr4 gene.Science. 1998; 282: 2085-2088Crossref PubMed Scopus (6379) Google Scholar). Small synthetic peptides based on the BB loop sequence can act as inhibitors of TIR-TIR interactions and of TLR or IL-1 signal transduction (20Toshchakov V.U. Basu S. Fenton M.J. Vogel S.N. Differential involvement of BB loops of toll-IL-1 resistance (TIR) domain-containing adapter proteins in TLR4- versus TLR2-mediated signal transduction.J. Immunol. 2005; 175: 494-500Crossref PubMed Scopus (77) Google Scholar, 21Toshchakov V.Y. Fenton M.J. Vogel S.N. Cutting Edge. Differential inhibition of TLR signaling pathways by cell-permeable peptides representing BB loops of TLRs.J. Immunol. 2007; 178: 2655-2660Crossref PubMed Scopus (66) Google Scholar, 22Bartfai T. Behrens M.M. Gaidarova S. Pemberton J. Shivanyuk A. Rebek Jr., J. A low molecular weight mimic of the Toll/IL-1 receptor/resistance domain inhibits IL-1 receptor-mediated responses.Proc. Natl. Acad. Sci. U.S.A. 2003; 100: 7971-7976Crossref PubMed Scopus (109) Google Scholar, 23Loiarro M. Sette C. Gallo G. Ciacci A. Fantò N. Mastroianni D. Carminati P. Ruggiero V. Peptide-mediated interference of TIR domain dimerization in MyD88 inhibits interleukin-1-dependent activation of NF-κB.J. Biol. Chem. 2005; 280: 15809-15814Abstract Full Text Full Text PDF PubMed Scopus (149) Google Scholar, 24Loiarro M. Capolunghi F. Fantò N. Gallo G. Campo S. Arseni B. Carsetti R. Carminati P. De Santis R. Ruggiero V. Sette C. Pivotal Advance. Inhibition of MyD88 dimerization and recruitment of IRAK1 and IRAK4 by a novel peptidomimetic compound.J. Leukocyte Biol. 2007; 82: 801-810Crossref PubMed Scopus (140) Google Scholar). Peptidomimetics of the BB loop exert a similar inhibitory effect on TLR signaling and have anti-inflammatory properties in vivo (22Bartfai T. Behrens M.M. Gaidarova S. Pemberton J. Shivanyuk A. Rebek Jr., J. A low molecular weight mimic of the Toll/IL-1 receptor/resistance domain inhibits IL-1 receptor-mediated responses.Proc. Natl. Acad. Sci. U.S.A. 2003; 100: 7971-7976Crossref PubMed Scopus (109) Google Scholar, 24Loiarro M. Capolunghi F. Fantò N. Gallo G. Campo S. Arseni B. Carsetti R. Carminati P. De Santis R. Ruggiero V. Sette C. Pivotal Advance. Inhibition of MyD88 dimerization and recruitment of IRAK1 and IRAK4 by a novel peptidomimetic compound.J. Leukocyte Biol. 2007; 82: 801-810Crossref PubMed Scopus (140) Google Scholar)The TLR10 crystal structure was proposed as a good model for TLR TIR-TIR dimerization, with an interface formed by the DD loop, BB loop, and αC helix (15Nyman T. Stenmark P. Flodin S. Johansson I. Hammarström M. Nordlund P. The crystal structure of the human toll-like receptor 10 cytoplasmic domain reveals a putative signaling dimer.J. Biol. Chem. 2008; 283: 11861-11865Abstract Full Text Full Text PDF PubMed Scopus (161) Google Scholar). The BB loops in this dimer interact with the reciprocal BB loop and αC helix, explaining how BB loop peptides and peptidomimetics can inhibit TIR-TIR interactions (15Nyman T. Stenmark P. Flodin S. Johansson I. Hammarström M. Nordlund P. The crystal structure of the human toll-like receptor 10 cytoplasmic domain reveals a putative signaling dimer.J. Biol. Chem. 2008; 283: 11861-11865Abstract Full Text Full Text PDF PubMed Scopus (161) Google Scholar).In 2002, Ronni et al. (25Ronni T. Agarwal V. Haykinson M. Haberland M.E. Cheng G. Smale S.T. Common interaction surfaces of the toll-like receptor 4 cytoplasmic domain stimulate multiple nuclear targets.Mol. Cell. Biol. 2003; 23: 2543-2555Crossref PubMed Scopus (48) Google Scholar) published an alanine scan mutagenesis study of the TLR4 TIR domain. Mapping of the mutations on a TLR4 TIR homology model revealed the importance of at least two surface patches, corresponding to the BB loop and to the DD loop and residues in the αC′ helix. Interestingly, none of the mutations in this study showed specificity in their effects for any of the different pathways. This led to the suggestion that pathways diverge downstream of the adapters or that different adapters all bind to the same TLR4 TIR-binding sites.The mammalian protein-protein interaction trap (MAPPIT) technique allows studying TIR-TIR interactions in detail in situ in intact living cells (26Ulrichts P. Peelman F. Beyaert R. Tavernier J. MAPPIT analysis of TLR adapter complexes.FEBS Lett. 2007; 581: 629-636Crossref PubMed Scopus (25) Google Scholar). In this study, we use this method plus NF-κB and IRF-3 reporter assays in combination with site-directed mutagenesis and homology modeling to determine the specific interaction sites for dimerization or oligomerization and adapter recruitment in the TLR4 TIR domain. We developed an assay in which we can specifically detect the TLR4-TLR4, TLR4-MAL, and TLR4-TRAM TIR-TIR interactions. Mutations in two binding sites simultaneously affect all three interactions. We propose a model based on the TLR10 TIR domain structure, in which TLR TIR dimerization is required for formation of an extended binding platform for both the MAL and TRAM adapters.DISCUSSIONA crucial event in TLR signaling is the complex formation between the TIR domains of the dimerized or oligomerized receptor and the TIR domain-containing adapter proteins. The structures of different TIR domains have been determined, and the importance of different structural elements as the BB-loop has been demonstrated (1Gay N.J. Gangloff M. Structure and function of Toll receptors and their ligands.Annu. Rev. Biochem. 2007; 76: 141-165Crossref PubMed Scopus (505) Google Scholar, 39Monie T.P. Moncrieffe M.C. Gay N.J. Structure and regulation of cytoplasmic adapter proteins involved in innate immune signaling.Immunol. Rev. 2009; 227: 161-175Crossref PubMed Scopus (31) Google Scholar). Different models for TIR-TIR interactions have been proposed, either based on structural data or on signaling data. However, the structure of a TLR-adapter complex has not been reported, and the architecture of TLR complexes is not yet completely understood. MAPPIT allows studying the separate TIR-TIR interactions, which makes it possible to detect residues or regions that affect one of the interactions. We established MAPPIT assays to detect TLR4ic-TLR4ic, TLR4ic-MAL, and TLR4ic-TRAM interactions, and we were able to show that mutations specifically involved in one of the interactions disturb the MAPPIT signal. Based on homology modeling, sequence conservation, and the results of an alanine scanning experiment of Ronni et al. (25Ronni T. Agarwal V. Haykinson M. Haberland M.E. Cheng G. Smale S.T. Common interaction surfaces of the toll-like receptor 4 cytoplasmic domain stimulate multiple nuclear targets.Mol. Cell. Biol. 2003; 23: 2543-2555Crossref PubMed Scopus (48) Google Scholar), we selected three possible binding sites in the TLR4 TIR domain.Mutations in all three possible binding sites abrogate TLR4 TIR-TLR4 TIR interactions, whereas adapter binding is only affected by mutations in binding site I and II. Only potential binding sites I and II in the TLR4 TIR domain are critical for LPS-induced NF-κB signaling, whereas an IRF3/GAL4-based assay suggests that binding site III may be important for IRF-3 activation. Binding site I contains residues of the αA and αB helix and of the BB and BC loop. Binding site II contains residues of the BB loop, DD loop, and αC helix.Binding site II approximately corresponds with the interface found in the dimer of the TLR10 TIR domain crystal structure (15Nyman T. Stenmark P. Flodin S. Johansson I. Hammarström M. Nordlund P. The crystal structure of the human toll-like receptor 10 cytoplasmic domain reveals a putative signaling dimer.J. Biol. Chem. 2008; 283: 11861-11865Abstract Full Text Full Text PDF PubMed Scopus (161) Google Scholar), which was proposed as a good model for TLR TIR dimerization (15Nyman T. Stenmark P. Flodin S. Johansson I. Hammarström M. Nordlund P. The crystal structure of the human toll-like receptor 10 cytoplasmic domain reveals a putative signaling dimer.J. Biol. Chem. 2008; 283: 11861-11865Abstract Full Text Full Text PDF PubMed Scopus (161) Google Scholar). In a model for a TLR4 dimer based on this structure, binding site II forms the interface between two TLR4 TIR domains. The BB loops of two TLR TIR domains interact at the TLR TIR interface but are at the same time exposed, forming a possible interaction site for adapter recruitment (15Nyman T. Stenmark P. Flodin S. Johansson I. Hammarström M. Nordlund P. The crystal structure of the human toll-like receptor 10 cytoplasmic domain reveals a putative signaling dimer.J. Biol. Chem. 2008; 283: 11861-11865Abstract Full Text Full Text PDF PubMed Scopus (161) Google Scholar). The exposed BB loops are part of the adjacent binding sites I of both TLR4 TIR domains. These adjacent binding sites I form a more extended platform, which may be important for adapter binding. An important role for this platform in TLR4 signaling is supported by our MAPPIT data, by residue conservation, and by the alanine scan data of Ronni et al. (25Ronni T. Agarwal V. Haykinson M. Haberland M.E. Cheng G. Smale S.T. Common interaction surfaces of the toll-like receptor 4 cytoplasmic domain stimulate multiple nuclear targets.Mol. Cell. Biol. 2003; 23: 2543-2555Crossref PubMed Scopus (48) Google Scholar) (Fig. 9).This extended platform may allow binding of two adapter molecules. This would be consistent with the existence of three types of interfaces, as postulated by Xu et al. (12Xu Y. Tao X. Shen B. Horng T. Medzhitov R. Manley J.L. Tong L. Structural basis for signal transduction by the Toll/interleukin-1 receptor domains.Nature. 2000; 408: 111-115Crossref PubMed Scopus (221) Google Scholar), when reporting the first TIR domain crystal structures. Binding site II between two TLR4 TIR domains would correspond to the “R” face. The extended platform formed by two binding sites I of TLR4 forms the “S” face between the TIR domains of the TLR and the adapters. These adapter molecules presumably bind as dimers that interact via the “A” face (Fig. 9G).Núñez Miguel l et al. (38Núñez Miguel R. Wong J. Westoll J.F. Brooks H.J. O'Neill L.A. Gay N.J. Bryant C.E. Monie T.P. A dimer of the Toll-like receptor 4 cytoplasmic domain provides a specific scaffold for the recruitment of signaling adapter proteins.PLoS One. 2007; 2: e788Crossref PubMed Scopus (151) Google Scholar) presented a similar TLR4 TIR model based on the dimer structure of the TLR10 TIR domain. These authors used in silico protein-protein docking of homology models to predict the binding site for the adapters TRAM and MAL on this TLR4 dimer. Both adapters were predicted to bind at symmetry-related sites at the TLR4 dimer interface indicated in Fig. 9, D and F. These predicted docking sites are not particularly conserved, and mutations at these sites do not affect adapter binding in our MAPPIT assays nor any of the tested TLR4 signaling pathways in the study of Ronni et al. (25Ronni T. Agarwal V. Haykinson M. Haberland M.E. Cheng G. Smale S.T. Common interaction surfaces of the toll-like receptor 4 cytoplasmic domain stimulate multiple nuclear targets.Mol. Cell. Biol. 2003; 23: 2543-2555Crossref PubMed Scopus (48) Google Scholar). We therefore favor a model with two adjacent binding sites I as binding sites for MAL and TRAM.The MAPPIT technique allows detecting mutations that affect binding specificity for different interaction partners. Nevertheless, in this study, we did not find mutations that specifically affect adapter recruitment. Instead, we find that mutations in binding site I and II affect both the TLR4-TLR4 and TLR4-adapter interactions in MAPPIT and AlphaScreenTM assays. This indicates that the TLR4 TIR domain needs to dimerize to allow recruitment of MAL and TRAM. Conversely, we were able to show that overexpression of TRAM enhances dimerization of the intracellular TLR4 domain. This suggests that binding of MAL or TRAM can stabilize the TLR4 TIR dimerization in our MAPPIT assays. This cooperativity between TLR4 TIR dimerization and adapter recruitment can explain why we did not detect any mutation that affects adapter-receptor TIR-TIR interaction without affecting receptor-receptor TIR-TIR interaction. Interestingly, the chemical compound TAK-242 specifically targets Cys-747 in binding site II in TLR4 and inhibits the MyD88-dependent and -independent TLR4 signaling pathways (40Takashima K. Matsunaga N. Yoshimatsu M. Hazeki K. Kaisho T. Uekata M. Hazeki O. Akira S. Iizawa Y. Ii M. Analysis of binding site for the novel small molecule TLR4 signal transduction inhibitor TAK-242 and its therapeutic effect on mouse sepsis model.Br. J. Pharmacol. 2009; 157: 1250-1262Crossref PubMed Scopus (170) Google Scholar). We suggest that this compound inhibits TLR4 TIR dimerization and therefore adapter recruitment.All mutations that affect MAL binding also affect TRAM binding in our MAPPIT assays, and our data suggest that the binding sites for MAL and TRAM on TLR4 strongly overlap. In line with this, thorough alanine scanning analysis of the TLR4 TIR domain by Ronni et al. (25Ronni T. Agarwal V. Haykinson M. Haberland M.E. Cheng G. Smale S.T. Common interaction surfaces of the toll-like receptor 4 cytoplasmic domain stimulate multiple nuclear targets.Mol. Cell. Biol. 2003; 23: 2543-2555Crossref PubMed Scopus (48) Google Scholar) did not find any mutations that affect specific signal transduction pathways. In our MAPPIT assays, MAL and TRAM seem to compete for this common or overlapping binding site, which in our model is formed by the adjacent binding sites I. It is unclear whether this competition plays a role in TLR4 signal transduction, as the MAL/MyD88 signaling pathway starts at the plasma membrane, whereas the TRAM/TRIF-dependent pathway requires endocytosis (6Kagan J.C. Medzhitov R. Phosphoinositide-mediated adapter recruitment controls Toll-like receptor signaling.Cell. 2006; 125: 943-955Abstract Full Text Full Text PDF PubMed Scopus (660) Google Scholar, 7Kagan J.C. Su T. Horng T. Chow A. Akira S. Medzhitov R. TRAM couples endocytosis of Toll-like receptor 4 to the induction of interferon-β.Nat. Immunol. 2008; 9: 361-368Crossref PubMed Scopus (931) Google Scholar).The model presented here for TLR TIR domain dimerization and adapter recruitment may apply for most if not all TLR TIR domains. Analysis of conservation of a TLR2 and TLR10 dimer for example shows a similar conserved binding site I platform (data not shown). Interestingly, TLR1 acquires the ability to bind MyD88 after mutation of residue 672 in its box1 motif (41Brown V. Brown R.A. Ozinsky A. Hesselberth J.R. Fields S. Binding specificity of Toll-like receptor cytoplasmic domains.Eur. J. Immunol. 2006; 36: 742-753Crossref PubMed Scopus (50) Google Scholar). This residue corresponds to residue Asp-711 in binding site I of TLR4. Mutation of Arg-748, Phe-749, Leu-752, and Arg-753 in the DD loop and αD helix of TLR2 decreases TLR2/TLR1 signaling (42Gautam J.K. Ashish Comeau L.D. Krueger J.K. Smith Jr., M.F. Structural and functional evidence for the role of the TLR2 DD loop in TLR1/TLR2 heterodimerization and signaling.J. Biol. Chem. 2006; 281: 30132-30142Abstract Full Text Full Text PDF PubMed Scopus (93) Google Scholar). These residues are in or at the edge of the predicted binding site II, which may form the TLR-TLR TIR-TIR interface in TLR2-mediated signaling.Although mutations in predicted binding site I and II in this work affect all tested aspects of TLR4 signal transduction, we find that mutations in binding site III only affect the TLR4 TIR-TLR4 TIR interaction in our MAPPIT assay. Most mutations in binding site III did not strongly affect TLR4-induced NF-κB signaling or MAL or TRAM recruitment. Interestingly, our data suggest that binding site III may be specifically involved in IRF-3 activation. This is probably not a consequence of defective TRAM binding, but it may be related to the effect of binding site III mutations on the TLR4-TLR4 interaction as observed via MAPPIT. The inhibitory effect of the site III mutations on TLR4ic-TLR4ic interaction could be rescued by overexpression of TRAM. This probably means that binding site III mutations only affect the weak interaction between isolated TLR4ic domains. The mutations lose their effect when this interaction is stabilized or enhanced by overexpression of TRAM or by additional interactions in the activated full-length TLR4 receptor complex. We cannot rule out a role for this area of the TIR domain for receptor oligomerization. The higher order MyD88-IRAK4 “myddosome” complexes suggest that TLR4 may indeed form oligomers upon activation (4Gay N.J. Gangloff M. O'Neill L.A. What the Myddosome structure tells us about the initiation of innate immunity.Trends Immunol. 2011; 32: 104-109Abstract Full Text Full Text PDF PubMed Scopus (134) Google Scholar).It is unclear whether equivalents of the binding sites defined in this work are present in the adapters MAL, MyD88, TRAM, and TRIF. The inhibitory effect of BB loop mutations on adapter functionality suggests that they may use similar type I- and II-binding sites for interaction via the “S interfaces” and “A interfaces” as defined above. Ohnishi et al. (16Ohnishi H. Tochio H. Kato Z. Orii K.E. Li A. Kimura T. Hiroaki H. Kondo N. Shirakawa M. Structural basis for the multiple interactions of the MyD88 TIR domain in TLR4 signaling.Proc. Natl. Acad. Sci. U.S.A. 2009; 106: 10260-10265Crossref PubMed Scopus (166) Google Scholar) reported three possible binding sites in their MyD88 structure, based on the effects of MyD88 TIR mutations on the inhibitory capacity of the MyD88 TIR domain in TLR4-mediated NF-κB activation. Binding sites II and III in this study were reported to mediate interaction with MAL. Superposition and alignment of the MyD88 and TLR4 structures and sequences show that these sites correspond to our binding sites I and III. Mutations of MAL at position Asp-198 inhibit TLR2 and TLR4 signaling and affect its interaction with TLR4 and MyD88 (43Ulrichts P. Bovijn C. Lievens S. Beyaert R. Tavernier J. Peelman F. Caspase-1 targets the TLR adapter Mal at a crucial TIR-domain interaction site.J. Cell Sci. 2010; 123: 256-265Crossref PubMed Scopus (22) Google Scholar, 44Miggin S.M. Pålsson-McDermott E. Dunne A. Jefferies C. Pinteaux E. Banahan K. Murphy C. Moynagh P. Yamamoto M. Akira S. Rothwell N. Golenbock D. Fitzgerald K.A. O'Neill L.A. NF-κB activation by the Toll-IL-1 receptor domain protein MyD88 adapter-like is regulated by caspase-1.Proc. Natl. Acad. Sci. U.S.A. 2007; 104: 3372-3377Crossref PubMed Scopus (99) Google Scholar). Asp-198 is found in a position that overlaps with the binding site III as defined in this study (43Ulrichts P. Bovijn C. Lievens S. Beyaert R. Tavernier J. Peelman F. Caspase-1 targets the TLR adapter Mal at a crucial TIR-domain interaction site.J. Cell Sci. 2010; 123: 256-265Crossref PubMed Scopus (22) Google Scholar).In conclusion, we demonstrated the importance of two binding sites in TLR4 adapter binding and signaling. Our data support a model of TLR4 TIR domain dimerization as found in the TLR10 TIR domain crystal structure. This dimerization is required for formation of a large conserved platform that contains the BB loop and box 1 motifs and that forms a potential binding site for the adapters MAL and TRAM. MAL and TRAM both bind to this platform, and adapter binding stabilizes the complex. It remains to be determined how MAL and TRAM interact with this binding site and how this leads to recruitment of MyD88. The MAPPIT method allows the detection of TLR4-MAL, TLR4-TRAM, MAL-MAL, and MAL-MyD88 interactions. A strategy that combines MAPPIT with mutagenesis of the adapter proteins as applied in this study can help to further define the interfaces in the TLR-adapter complexes. IntroductionToll-like receptors (TLRs) 3The abbreviations used are: TLRToll-like receptorTIR domainToll/interleukin-1 receptor domainMALMyD88 adapter-likeTrifTIR-domain-containing adapter inducing interferon-βTRAMTRIF-related adapter moleculeMAPPITmammalian protein-protein interaction trapTricineN-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]glycineSVTSV40 large T. are pathogen recognition receptors that play a crucial role in innate immunity (1Gay N.J. Gangloff M. Structure and function of Toll receptors and their ligands.Annu. Rev. Biochem. 2007; 76: 141-165Crossref PubMed Scopus (505) Google Scholar, 2Hennessy E.J. Parker A.E. O'Neill L.A. Targeting Toll-like receptors. Emerging therapeutics.Nat. Rev. Drug Discov. 2010; 9: 293-307Crossref PubMed Scopus (630) Google Scholar, 3Kawai T. Akira S. The role of pattern-recognition receptors in innate immunity. Update on Toll-like receptors.Nat. Immunol. 20" @default.
• W2006348886 created "2016-06-24" @default.
• W2006348886 creator A5024963119 @default.
• W2006348886 creator A5029827503 @default.
• W2006348886 creator A5032088939 @default.
• W2006348886 creator A5054960368 @default.
• W2006348886 creator A5054994879 @default.
• W2006348886 creator A5058460889 @default.
• W2006348886 creator A5080918885 @default.
• W2006348886 date "2012-02-01" @default.
• W2006348886 modified "2023-10-11" @default.
• W2006348886 title "Identification of Interaction Sites for Dimerization and Adapter Recruitment in Toll/Interleukin-1 Receptor (TIR) Domain of Toll-like Receptor 4" @default.
• W2006348886 cites W1872584468 @default.
• W2006348886 cites W1928414651 @default.
• W2006348886 cites W1966772446 @default.
• W2006348886 cites W1970666401 @default.
• W2006348886 cites W1970809104 @default.
• W2006348886 cites W1972294481 @default.
• W2006348886 cites W1975958440 @default.
• W2006348886 cites W1991931339 @default.
• W2006348886 cites W2001256354 @default.
• W2006348886 cites W2002301799 @default.
• W2006348886 cites W2013469022 @default.
• W2006348886 cites W2015045770 @default.
• W2006348886 cites W2015833994 @default.
• W2006348886 cites W2033830134 @default.
• W2006348886 cites W2043823247 @default.
• W2006348886 cites W2046743509 @default.
• W2006348886 cites W2051521460 @default.
• W2006348886 cites W2054979063 @default.
• W2006348886 cites W2056812842 @default.
• W2006348886 cites W2062835892 @default.
• W2006348886 cites W2067662106 @default.
• W2006348886 cites W2082890018 @default.
• W2006348886 cites W2087494383 @default.
• W2006348886 cites W2088768592 @default.
• W2006348886 cites W2089217951 @default.
• W2006348886 cites W2091176630 @default.
• W2006348886 cites W2094148186 @default.
• W2006348886 cites W2097382368 @default.
• W2006348886 cites W2102502076 @default.
• W2006348886 cites W2109491705 @default.
• W2006348886 cites W2111428445 @default.
• W2006348886 cites W2115185894 @default.
• W2006348886 cites W2116455233 @default.
• W2006348886 cites W2119747146 @default.
• W2006348886 cites W2122242846 @default.
• W2006348886 cites W2129319296 @default.
• W2006348886 cites W2132629607 @default.
• W2006348886 cites W2145907407 @default.
• W2006348886 cites W2147038697 @default.
• W2006348886 cites W2147903280 @default.
• W2006348886 cites W2149071811 @default.
• W2006348886 cites W2167593547 @default.
• W2006348886 cites W2168058007 @default.
• W2006348886 cites W2171371554 @default.
• W2006348886 cites W95014119 @default.
• W2006348886 doi "https://doi.org/10.1074/jbc.m111.282350" @default.
• W2006348886 hasPubMedCentralId "https://www.ncbi.nlm.nih.gov/pmc/articles/3281722" @default.
• W2006348886 hasPubMedId "https://pubmed.ncbi.nlm.nih.gov/22139835" @default.
• W2006348886 hasPublicationYear "2012" @default.
• W2006348886 type Work @default.
• W2006348886 sameAs 2006348886 @default.
• W2006348886 citedByCount "60" @default.
• W2006348886 countsByYear W20063488862012 @default.
• W2006348886 countsByYear W20063488862013 @default.
• W2006348886 countsByYear W20063488862014 @default.
• W2006348886 countsByYear W20063488862015 @default.
• W2006348886 countsByYear W20063488862016 @default.
• W2006348886 countsByYear W20063488862017 @default.
• W2006348886 countsByYear W20063488862018 @default.
• W2006348886 countsByYear W20063488862019 @default.
• W2006348886 countsByYear W20063488862020 @default.
• W2006348886 countsByYear W20063488862021 @default.
• W2006348886 countsByYear W20063488862022 @default.
• W2006348886 countsByYear W20063488862023 @default.
• W2006348886 crossrefType "journal-article" @default.
• W2006348886 hasAuthorship W2006348886A5024963119 @default.
• W2006348886 hasAuthorship W2006348886A5029827503 @default.
• W2006348886 hasAuthorship W2006348886A5032088939 @default.
• W2006348886 hasAuthorship W2006348886A5054960368 @default.
• W2006348886 hasAuthorship W2006348886A5054994879 @default.
• W2006348886 hasAuthorship W2006348886A5058460889 @default.
• W2006348886 hasAuthorship W2006348886A5080918885 @default.
• W2006348886 hasBestOaLocation W20063488861 @default.
• W2006348886 hasConcept C116834253 @default.
• W2006348886 hasConcept C119599485 @default.
• W2006348886 hasConcept C127413603 @default.
• W2006348886 hasConcept C134306372 @default.
• W2006348886 hasConcept C136449434 @default.
• W2006348886 hasConcept C170493617 @default.
• W2006348886 hasConcept C177284502 @default.
• W2006348886 hasConcept C183786373 @default.
• W2006348886 hasConcept C185592680 @default.
• W2006348886 hasConcept C18903297 @default.
• W2006348886 hasConcept C203014093 @default.
• W2006348886 hasConcept C2776709828 @default.
• W2006348886 hasConcept C2777977768 @default.

• next