Identification of Molecular Interactions Between a Chemokine Receptor and Ligand

描述（由申请人提供）：趋化因子及其受体参与先天和适应性免疫反应；然而，趋化因子和受体的不适当激活或表达已在几种疾病中被发现，如动脉粥样硬化、多发性硬化、哮喘和类风湿性关节炎。虽然趋化因子网络对宿主防御至关重要，但对受体被配体激活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（gpcr）家族。gpcr的特点是7个跨膜螺旋在细胞内与异源三聚体g蛋白偶联。激动剂诱导的趋化因子受体的激活导致构象变化，触发g蛋白的下游信号传导。为此，本培训计划的目标是阐明趋化因子激动剂MCP-3激活趋化因子受体CCR1的分子机制。像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。本提案的具体目的如下：(1)与UCSD的Woods实验室合作，我们将使用增强氘交换质谱（DXMS）来识别MCP-3:CCR1复合物之间的相互作用表面。(2)对CCR1细胞外环区域进行诱变，鉴定参与配体结合和活化的特异性残基。单独地，这两种方法将为趋化因子受体-配体相互作用提供重要的见解，但综合起来，它们提供了CCR1:MCP-3相互作用的全面分析。因此，识别和理解这些特殊的相互作用将有助于开发CCR1的小分子拮抗剂，因为CCR1参与多种疾病。与公共卫生相关：趋化因子在我们的免疫系统反应中发挥重要作用；然而，趋化因子和受体的不适当活动可导致炎症性疾病，如动脉粥样硬化、多发性硬化症和类风湿性关节炎。因此，从这些趋化因子受体的研究中获得的结构和功能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.