Molecular definition of the endogenous Toll-like receptor signalling pathways

• 成果类型: Article
• 署名作者: Fisch, Daniel; Zhang, Tian; Sun, He; Ma, Weiyi; Tan, Yunhao; Gygi, Steven P.; Higgins, Darren E.; Kagan, Jonathan C.
• 署名单位: Harvard University; Harvard University Medical Affiliates; Boston Children's Hospital; Harvard University; Harvard Medical School; Harvard University; Harvard Medical School; University of Virginia; University of Virginia; Harvard University; Harvard Medical School
• 刊物名称: Nature
• ISSN/ISSBN: 0028-4498
• DOI: 10.1038/s41586-024-07614-7
• 发表日期: 2024-07-18
• 关键词: nf-kappa-b; myd88; kinase; RECOGNITION; protein; activation; platform; complex; macrophages; myddosome

摘要

Innate immune pattern recognition receptors, such as the Toll-like receptors (TLRs), are key mediators of the immune response to infection and central to our understanding of health and disease1. After microbial detection, these receptors activate inflammatory signal transduction pathways that involve I kappa B kinases, mitogen-activated protein kinases, ubiquitin ligases and other adaptor proteins. The mechanisms that connect the proteins in the TLR pathways are poorly defined. To delineate TLR pathway activities, we engineered macrophages to enable microscopy and proteomic analysis of the endogenous myddosome constituent MyD88. We found that myddosomes form transient contacts with activated TLRs and that TLR-free myddosomes are dynamic in size, number and composition over the course of 24 h. Analysis using super-resolution microscopy revealed that, within most myddosomes, MyD88 forms barrel-like structures that function as scaffolds for effector protein recruitment. Proteomic analysis demonstrated that myddosomes contain proteins that act at all stages and regulate all effector responses of the TLR pathways, and genetic analysis defined the epistatic relationship between these effector modules. Myddosome assembly was evident in cells infected with Listeria monocytogenes, but these bacteria evaded myddosome assembly and TLR signalling during cell-to-cell spread. On the basis of these findings, we propose that the entire TLR signalling pathway is executed from within the myddosome. Myddosomes, in which MyD88 forms barrel-like scaffold structures for effector protein recruitment and activation, contain proteins that act at all stages and regulate all effector responses of the TLR signalling pathways.