Structural studies of human extracellular calcium-sensing receptor

人细胞外钙敏感受体的结构研究

• 批准号: 9293333
• 负责人: QING R FAN
• 金额: $ 31.6万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9293333
• 关键词: Affect; Affinity; Agonist; Alzheimer' s Disease; Amino Acids; Binding; Binding Sites; Biological Process; Bone Diseases; Calcium; Calcium-Sensing Receptors; Calmodulin; Cell Extracts; Cell membrane; Cell surface; Cells; Clinical; Complex; Cryoelectron Microscopy; Crystallization; Cytoplasmic Receptors; Cytoplasmic Tail; Detergents; Dimerization; Disease; Disulfides; Equilibrium; Event; Exhibits; Extracellular Domain; Fetal Development; G-Protein-Coupled Receptors; G-substrate; GTP-Binding Protein alpha Subunits, Gs; GTP-Binding Proteins; Goals; Heterotrimeric GTP-Binding Proteins; Homeostasis; Homodimerization; Homology Modeling; Human; Inositol Phosphates; Insecta; Intracellular Signaling Proteins; Ions; Lead; Length; Life; Ligand Binding; Ligands; Maintenance; Malignant Neoplasms; Mammalian Cell; Maps; Measures; Metabolism; Methods; Minerals; Molecular; Molecular Conformation; Monitor; Mutation; PTH gene; Phenylalanine; Physiological; Play; Proteins; Receptor Activation; Receptor Gene; Regulation; Research; Rest; Role; Signal Pathway; Signal Transduction; Signaling Molecule; Site; Specificity; Stimulus; Structural Models; Structure; System; Therapeutic Agents; Transmembrane Domain; X-Ray Crystallography; base; cinacalcet; design; detection of nutrient; dimer; extracellular; information model; neuronal excitability; novel therapeutics; public health relevance; receptor; receptor function; response

 DESCRIPTION (provided by applicant): Human extracellular calcium-sensing receptor (CaSR) is a G-protein coupled receptor that maintains Ca2+ homeostasis through the regulation of parathyroid hormone secretion. CaSR also plays important roles in biological processes unrelated to Ca2+ balance such as fetal development. Abnormalities in the CaSR gene are associated with a vareity of Ca2+ homeostatic disorders including potentially life threatening hypercalcaemic conditions. Altered expression of CaSR has also been implicated in other diseases including cancer and Alzheimer's disease. Cinacalcet, an allosteric modulator of CaSR, is used clinically to treat disorders of bone and mineral metabolism. Therefore, elucidating the structure of CaSR may assist the design of valuable therapeutic agents. CaSR functions as a disulfide-tethered homodimer. It activates a diverse array of signaling pathways in a ligand-specific manner. In addition to its principal agonist, extracellular Ca2+, CaSR responds to a variety of agonists, and its activity is regulated by postive and negative allosteric modulators. The first part of this proposal is aimed at understanding the mechanisms by which CaSR recognizes structurally distinct ligands while maintaining binding affinity and specificity. We propose to solve the crystal structures of CaSR ectodomain bound to different agonists and allosteric modulators. The second aim is to identify the conformational changes associated with receptor activation based on the structures of CaSR ectodomain in the resting and active states. We plan to measure the functional effects of mutations that are designed based on these structures to probe the ligand binding sites and homodimer interface. The third part of the proposed research is to elucidate the signal transduction mechanism of CaSR by solving the structures of full-length receptor and its complexes with downstream signaling molecules. A combination of structural and functional analysis of CaSR will advance our understanding of the molecular basis of extracellular Ca2+ sensing and the general activation mechanisms of GPCR dimers.

 描述（由申请人提供）：人细胞外钙敏感受体（CaSR）是一种G蛋白偶联受体，通过调节甲状旁腺激素分泌维持Ca2+稳态。CaSR还在与Ca2+平衡无关的生物学过程中发挥重要作用，如胎儿发育。CaSR基因的缺失与多种Ca2+稳态紊乱相关，包括潜在的危及生命的高钙血症。CaSR的表达改变也涉及其他疾病，包括癌症和阿尔茨海默病。西那卡塞是一种CaSR的变构调节剂，临床上用于治疗骨和矿物质代谢疾病。因此，阐明CaSR的结构可能有助于设计有价值的治疗药物。CaSR作为二硫键连接的同源二聚体发挥作用。它以配体特异性方式激活多种信号通路。除了其主要的激动剂，细胞外Ca 2+，CaSR响应于各种激动剂，其活性由正和负变构调节剂调节。该提案的第一部分旨在了解CaSR识别结构不同配体同时保持结合亲和力和特异性的机制。我们建议解决与不同激动剂和变构调节剂结合的CaSR胞外域的晶体结构。第二个目的是根据CaSR胞外域在静息和激活状态下的结构，确定与受体激活相关的构象变化。我们计划测量基于这些结构设计的突变的功能效应，以探测配体结合位点和同源二聚体界面。第三部分是通过解析CaSR全长受体及其与下游信号分子复合物的结构来阐明CaSR的信号转导机制。CaSR的结构和功能分析的结合将促进我们对细胞外Ca2+传感的分子基础和GPCR二聚体的一般激活机制的理解。