Identification of Molecular Interactions Between a Chemokine Receptor and Ligand

描述(申请人提供)：趋化因子及其受体参与先天免疫反应和获得性免疫反应；然而，在动脉粥样硬化、多发性硬化症、哮喘和类风湿性关节炎等几种疾病中发现了趋化因子和受体的不适当激活或表达。尽管趋化因子网络对宿主防御至关重要，但对配体激活受体的分子机制知之甚少。趋化因子受体属于视紫红质样G蛋白偶联受体家族。GPCRs的特征是7个跨膜螺旋在细胞内偶联到一个异源三聚体G蛋白上。激动剂诱导趋化因子受体的激活导致构象变化，从而触发G蛋白的下游信号。为此，本培训计划中提出的目标旨在阐明趋化因子受体CCR1被趋化因子激动剂MCP-3激活的分子机制。与许多趋化因子和趋化因子受体一样，MCP-3和CCR1可能在涉及单核细胞浸润的炎症性疾病的发病机制中发挥作用。这项建议的具体目标如下：(1)与加州大学圣地亚哥分校的伍兹实验室合作，我们将使用增强型氢交换质谱仪(DXMS)来识别MCP-3：CCR1复合体之间的相互作用表面。(2)对CCR1胞外环区进行突变，以确定参与配体结合和激活的特定残基。另外，这两种方法将提供对趋化因子受体-配体相互作用的重要见解，但综合起来，它们提供了对CCR1：MCP-3相互作用的全面分析。因此，识别和了解这些特殊的相互作用将有助于CCR1小分子拮抗剂的开发，因为它参与了几种疾病。与公共健康相关：趋化因子在我们的免疫系统反应中起主要作用；然而，趋化因子和受体的不适当活动可能导致炎症性疾病，如动脉粥样硬化、多发性硬化症和类风湿性关节炎。因此，从趋化因子受体的结构和功能研究中获得的知识将有助于我们对趋化因子受体-配体活性和功能的有限理解。这些信息可以指导炎症性疾病治疗中的治疗干预策略。

DESCRIPTION (provided by applicant): Chemokines and their receptors are involved in both the innate and adaptive immune response; however, inappropriate activation or expression of chemokines and receptors has been identified in several diseases such as atherosclerosis, multiple sclerosis, asthma, and rheumatoid arthritis. Although the chemokine network is crucial to host defense, little is known about the molecular mechanism of receptor activation by ligand. Chemokine receptors belong to the family of Rhodopsin-like G-protein coupled receptors (GPCRs). GPCRs are characterized by 7-transmembrane spanning helices coupled intracellularly to a heterotrimeric G-protein. Agonist-induced activation of chemokine receptors results in conformational changes that trigger downstream signaling of the G-protein. To this end, the objectives set forth in this training plan aim to elucidate the molecular mechanism of activation of the chemokine receptor, CCR1, by the chemokine agonist, MCP-3. Like many chemokines and chemokine receptors, MCP-3 and CCR1 likely play a role in the pathogenesis of inflammatory diseases that involve monocyte infiltration. The specific aims of this proposal are as follows: (1) In collaboration with the Woods lab here at UCSD, we will use enhanced deuterium exchange with Mass Spectrometry (DXMS) to identify the interaction surfaces between the MCP-3:CCR1 complex. (2) Carry out mutagenesis on the extracellular loop regions of CCR1 to identify specific residues involved in ligand binding and activation. Separately, these two approaches will provide significant insight into the chemokine receptor-ligand interactions, but taken together, they provide a comprehensive analysis of CCR1:MCP-3 interactions. Therefore, identifying and understanding these particular interactions will aid the development of small molecule antagonists of CCR1, given its involvement in several diseases. RELEVANCE TO PUBLIC HEALTH: Chemokines play a major role in our immune system response; however, inappropriate activity of chemokines and receptors can result in inflammatory diseases such as atherosclerosis, multiple sclerosis, and rheumatoid arthritis. Therefore, the structural and functional knowledge gained from these studies of the chemokine receptor will contribute to our limited understanding of chemokine receptor-ligand activity and function. This information can guide therapeutic interference strategies in the treatment of inflammatory diseases.