Activation of Toll-like receptors nucleates assembly of the MyDDosome signaling hub

Latty, Sarah L.; Sakai, Jiro; Hopkins, Lee; Verstak, Brett; Páramo, Teresa; Berglund, Nils; Cammarota, Eugenia; Cicuta, Pietro; Bond, Peter J.; Klenerman, David; Bryant, Clare

doi:10.7554/elife.31377

Cited by 97 publications

(124 citation statements)

References 42 publications

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“…This data complements the previous Myddosome data that shows assemblies of 6-8 MyD88 DDs 23 . Our results are also consistent with the recent single molecule fluorescence microscopy studies by Latty et al 23 demonstrating the formation of both smaller (6 MyD88 complexes approximately) and 'super' Myddosomes at the cell surface. Overall, the different domains exhibit unique oligomerisation propensities, with both domains presence necessary but not sufficient for the formation of polymers.…”

Section: At Low Concentrations Both the Tir And Death Domains Are Resupporting

confidence: 93%

“…For many years, TIR domain associations, which are weak and transient, have been seen to contribute little to the oligomerisation status of signalling proteins 27,28 . However, the recent cryoEM structure of Mal TIR domain in filamentous form, as well as novel studies 12 ,demonstrated that upon specific ligand binding TIR-containing proteins cooperatively assemble into large multiprotein complexes 12,23 . The TIR domain of MyD88 was also demonstrated to polymerise but only upon seeding by Mal filaments.…”

Section: Full-length Myd88 Biophysical Behaviour and Its Link To Signmentioning

confidence: 99%

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Effects of Pathological Mutations on the Prion-Like Polymerisation of MyD88

O’Carroll

Chauvin

Brown

et al. 2018

Preprint

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A novel concept has emerged whereby the higher-order self-assembly of proteins provides a simple and robust mechanism for signal amplification. This appears to be a universal signalling mechanism within the innate immune system, where the recognition of pathogens or danger-associated molecular patterns need to trigger a strong, binary response within cells. Previously, multiple structural studies have been limited to single domains, expressed and assembled at high protein concentrations. We therefore set out to develop new in vitro strategies to characterise the behaviour of full-length proteins at physiological levels. In this study we focus on the adaptor protein MyD88, which contains two domains with different self-assembly properties: a TIR domain that can polymerise similarly to the TIR domain of Mal, and a Death Domain that has been shown to oligomerise with helical symmetry in the Myddosome complex. To visualize the behaviour of fulllength MyD88 without purification steps, we use single-molecule fluorescence coupled to eukaryotic cell-free protein expression. These experiments demonstrate that at low protein concentration, only full-length MyD88 forms prion-like polymers. We also demonstrate that the metastability of MyD88 polymerisation creates the perfect binary response required in innate signalling: the system is silenced at normal concentrations but upstream signalling creates a "seed" that triggers polymerisation and amplification of the response. These findings pushed us to re-interpret the role of polymerisation in MyD88-related diseases and we studied the impact of disease-associated point mutations L93P, R196C and L252P/L265P at the molecular level. We discovered that all mutations completely block the ability of MyD88 to polymerise. We also confirm that L252P, a gain-of-function mutation, allows the MyD88 mutant to form extremely stable oligomers, even when expressed at low nanomolar concentrations. Thus, our results are consistent with and greatly add to the findings on the Myddosomes digital 'all-or-none' responses and the behaviour of the oncogenic mutation of MyD88.

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Section: At Low Concentrations Both the Tir And Death Domains Are Resupporting

confidence: 93%

Section: Full-length Myd88 Biophysical Behaviour and Its Link To Signmentioning

confidence: 99%

Effects of Pathological Mutations on the Prion-Like Polymerisation of MyD88

O’Carroll

Chauvin

Brown

et al. 2018

Preprint

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“…Despite the well-known function of TLR4 as an inflammatory player, it is not fully understood how TLR4, especially its intracellular TIR domain, forms a homo-oligomer upon LPS binding to the extracellular domain (17,30). It has been reported that TLR4 could exist as preformed dimers in the absence of ligand and that complete activation of TLR4 needs not only ligand binding but also apposition of the TIR domains (31). It has been long thought that additional factors proximal to the plasma membrane may facilitate the homoassociation of TLR4 during its activation.…”

Section: Discussionmentioning

confidence: 99%

TRAF3-interacting JNK-activating modulator promotes inflammation by stimulating translocation of Toll-like receptor 4 to lipid rafts

Guan

Wang

et al. 2019

Journal of Biological Chemistry

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Toll-like receptors (TLRs) are key players of the innate immune system and contribute to inflammation and pathogen clearance. Although TLRs have been extensively studied, it remains unclear how exactly bacterial lipopolysaccharide (LPS)induced conformational changes of the extracellular domain of the TLRs trigger the dimerization of their intracellular domain across the plasma membrane and thereby stimulate downstream signaling. Here, using LPS-stimulated THP-1-derived macrophages and murine macrophages along with immunoblotting and immunofluorescence and quantitative analyses, we report that in response to inflammatory stimuli, the coiled-coil protein TRAF3-interacting JNK-activating modulator (T3JAM) associates with TLR4, promotes its translocation to lipid rafts, and thereby enhances macrophage-mediated inflammation. T3JAM overexpression increased and T3JAM depletion decreased TLR4 signaling through both the MyD88-dependent pathway and TLR4 endocytosis. Importantly, deletion or mutation of T3JAM to disrupt its coiled-coil-mediated homoassociation abrogated TLR4 recruitment to lipid rafts. Consistently, T3JAM depletion in mice dampened TLR4 signaling and alleviated LPS-induced inflammatory damage. Collectively, our findings reveal an additional molecular mechanism by which TLR4 activity is regulated and suggest that T3JAM may function as a molecular clamp to "tighten up" TLR4 and facilitate its translocation to lipid rafts. cro ARTICLE 2744

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“…Thus, the IFN‐γ receptor complex joins other innate receptors that form higher order complexes of hexamers, dodecamers or more (e.g. the GM CSFR and TLR4) …”

mentioning

confidence: 99%

“…the GM CSFR and TLR4). 15,16 Mendoza et al used the structure to investigate the IFNGR2 mutation T168N that is associated with the lack of IFN-c responsiveness resulting in a predisposition to mycobacterial infection. 1 The asparagine in the IFNGR2T168N mutant sits in the interface of IFNGR2 with the IFNg/IFNGR1 complex.…”

mentioning

confidence: 99%