Structural biology of Toll like receptor/IL 1R signaling

Toll 样受体/IL 1R 信号传导的结构生物学

• 批准号: 6706324
• 负责人: LIANG TONG
• 金额: $ 29.84万
• 依托单位: COLUMBIA UNIV NEW YORK MORNINGSIDE
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-03-01 至 2006-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6706324
• 关键词: X ray crystallography; biological signal transduction; cell line; cytokine receptors; gene mutation; interleukin 1; protein structure function; recombinant proteins; site directed mutagenesis; stoichiometry

Toll-like receptors (TLRs) and members of the interleukin-1 receptor (IL-lR) superfamily have crucial roles in host innate immune response against microbial infections. For example, deletion of the TLR4 gene in mice renders them hyporesponsive to lipopolysaccharide (LPS, also known as endotoxin), which is a unique cell-wall component of Gram-negative bacteria. In mammals and other vertebrates, the innate immune response is also important for the activation of the proper adaptive immune response. The TLRs and the IL-1RS share a conserved intra-cellular domain, the Toll/Interleukin-1 Receptor (TIR) domain. The integrity of this domain is required for the signal transduction through these receptors. For example, a single-point mutation in the TIR domain of murine TLR4, P712H, leads to the abrogation of LPS responsiveness, similar to the phenotype of the TLR4-/- mice. Additional mutagenesis studies also confirm the importance of this domain in the signaling process. The signaling pathway of the TLRs and IL-1RS involves many molecules, such as the adapter molecule MyD88, the protein kinase IRAK, TRAF6, and other down-stream mediators. MyD88 is a cytoplasmic protein and it also contains a TIR domain. Ultimately, the signal transduction leads to the activation of the transcription factor NF-kappaB, the stress kinases and the AP-1 transcription factors. TIR domains are believed to be protein-protein interaction modules. Upon receptor activation by ligand binding, an intra-cellular signaling complex is formed via the TIR domains that are present in the receptors and the MyD88 adapter molecule. This is a crucial step in the signal transduction by these receptors. Currently, there is no structural information on any of the TIR domains. The proposed research project will fill this gap in our knowledge on these signal transduction modules. The structural information will be used to understand the biology and biochemistry of the TLRs and the IL-1RS. The information will also be used to identify residues that may be important for the signal transduction. These will form the basis for further mutagenesis, biochemical, and functional studies to assess their importance.

Toll样受体（TLR）和白细胞介素-1受体（IL-1 R）超家族成员在宿主针对微生物感染的先天免疫应答中具有关键作用。 例如，小鼠中TLR 4基因的缺失使它们对脂多糖（LPS，也称为内毒素）反应迟钝，脂多糖是革兰氏阴性细菌的独特细胞壁组分。 在哺乳动物和其他脊椎动物中，先天免疫应答对于适当的适应性免疫应答的激活也是重要的。 TLR和IL-1 RS共享保守的细胞内结构域，Toll/白细胞介素-1受体（TIR）结构域。 该结构域的完整性是通过这些受体进行信号转导所必需的。 例如，鼠TLR 4的TIR结构域中的单点突变P712 H导致LPS反应性的消除，类似于TLR 4-/-小鼠的表型。 另外的诱变研究也证实了该结构域在信号传导过程中的重要性。 TLR和IL-1 RS的信号传导通路涉及许多分子，如衔接分子MyD 88、蛋白激酶IRAK、TRAF 6和其他下游介质。 MyD 88是一种胞质蛋白，它也含有TIR结构域。 最终，信号转导导致转录因子NF-κ B、应激激酶和AP-1转录因子的激活。TIR结构域被认为是蛋白质-蛋白质相互作用模块。 在通过配体结合激活受体后，通过存在于受体和MyD 88衔接子分子中的TIR结构域形成细胞内信号传导复合物。 这是通过这些受体进行信号转导的关键步骤。目前，没有任何TIR结构域的结构信息。 拟议的研究项目将填补我们对这些信号转导模块知识的空白。 结构信息将用于了解TLR和IL-1 RS的生物学和生物化学。 该信息还将用于鉴定可能对信号转导重要的残基。 这些将为进一步的诱变、生物化学和功能研究奠定基础，以评估其重要性。