Structure-function studies on a key signaling module from interleukin 17 receptor

描述(申请人提供)：白介素17(IL17)在炎症性和自身免疫性疾病中起关键作用。在所有白介素17受体(IL17Rs)和接头蛋白核因子κB(NF-κB)激活物1(Act1)中发现了一个独特的细胞内信号转导结构域，称为SEFIR。IL17信号转导的一个关键步骤是通过SEFIR介导的关联将Act1招募到IL17Rs。作为所有IL17R中最大的受体，IL17RA是参与几乎所有IL17信号转导的关键受体，需要一个独特的结构模块(SEFEX)，该模块由SEFIR和一个短的侧翼C末端延伸组成。SEFEX介导的IL17RA信号的结构和机制尚不清楚。在本提案中，我们旨在提供IL17RA的SEFEX结构域的分子细节，并揭示SEFEX招募Act1进行IL17RA细胞内信号转导的分子原理。目的1.IL17RA SEFEX结构域的结构和功能研究。假设：IL17RA的细胞内信号模块在所有IL17受体中是独一无二的，它包含SEFIR和一个约100aA的C末端侧翼片段。与其他IL17R和ACT1相比，IL17RA SEFIR结构域本身采用了独特的结构。I)我们将确定IL17RA-SEFEX的晶体结构。Ii)我们将定位IL17RA SEFEX上的功能残基，这些残基对与Act1和IL17刺激的信号相互作用至关重要。我们将使用突变、CO-IP、表面等离子体共振和基于细胞的IL17信号分析。目的2.通过结构和功能研究确定IL17RA招募Act1的机制。假设：SEFIR结构域中的螺旋αC是一个保守的结构基序，参与了SEFIR-SEFIR的异型相互作用。因此，从ACT1、IL17RB或IL17RA的αC螺旋衍生的多肽将抑制IL17/IL25信号转导。I)我们将通过结构生物学来确定IL17RA招募Act1的分子机制。Ii)我们将开发细胞通透性抑制肽来抑制IL17信号。这些研究为发现调节IL17和IL25信号的新方法提供了机会。我们的目标是详细描述IL17RA独特的信号结构域，它是几乎所有IL17配体信号最常见的共有受体。预期的结果将为我们进一步了解IL17受体信号的基本原理提供详细的结构信息。我们的研究将为设计选择性抑制剂提供一个平台，这些抑制剂可能会进一步开发成针对一些炎症性和自身免疫性疾病的新疗法。

DESCRIPTION (provided by applicant): Interleukin 17 (IL17) plays a key role in mediating inflammatory and autoimmune diseases. A unique intracellular signaling domain termed 'SEFIR' was identified within all IL17 receptors (IL17Rs) and the adaptor protein, nuclear factor κB (NF-κB) activator 1 (Act1). A key step in IL17 signaling is the recruitment of Act1 to IL17Rs via SEFIR mediated associations. As the largest among all IL17Rs, IL17RA is a key receptor involved in essentially all IL17 signaling and requires a unique structural module (SEFEX) that is composed of both SEFIR and a short flanking C-terminal extension. The structure and mechanism of SEFEX-mediated IL17RA signaling are not known. In this proposal, we aim for providing molecular details of SEFEX domain from IL17RA, and revealing the molecular principles by which SEFEX recruits Act1 for IL17RA intracellular signaling. Aim 1. Structural and functional studies on the SEFEX domain of IL17RA. Hypothesis: The intracellular signaling module of IL17RA is unique among all IL17 receptors, and contains the SEFIR and a C-terminal flanking fragment of about 100 a.a. The IL17RA SEFIR domain itself adopts a unique structure, compared to that from other IL17Rs and Act1. I) We will determine the crystal structure of IL17RA-SEFEX. II) We will map the functional residues on IL17RA SEFEX that are critical for interaction with Act1 and IL17-stimulated signaling. We will use mutagenesis, CO-IP, surface plasmon resonance, and cell-based IL17 signaling assays. Aim 2. Determine the mechanism by which IL17RA recruits Act1 by structural and functional studies. Hypothesis: Helix αC in the SEFIR domains is a conserved structural motif involved in heterotypic SEFIR- SEFIR interactions. Therefore peptides derived from the αC helix of Act1, IL17RB or IL17RA will be inhibitory for IL17/IL25 signaling. I) We will determine the molecular mechanism by which IL17RA recruits Act1 by structural biology. II) We will develop cell-permeable inhibitory peptides for inhibition of IL17 signaling. These studies offer an opportunity for uncovering novel approaches for modulating IL17 and IL25 signaling. Our objectives are the detailed characterizations of the unique signaling domain from IL17RA, which is the most commonly shared receptor for nearly all IL17 ligands signaling. The expected results will provide detailed structural information for advancing our understanding on the fundamental principles of IL17 receptor signaling. Our studies will provide a platform for designing selective inhibitors that may be further developed into new therapeutics against a number of inflammatory and autoimmune diseases.