Structure-Function Studies & Molecular Interactions of Chemokines

结构功能研究

• 批准号: 8391260
• 负责人: Tracy M Handel
• 金额: $ 36.43万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-12-01 至 2015-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8391260
• 关键词: Acquired Immunodeficiency Syndrome; Adhesions; Affinity; Amino Acids; Asthma; Atherosclerosis; Atomic Force Microscopy; Binding; Binding Proteins; Biological Assay; Blood flow; Carbohydrates; Cell Adhesion; Cell Line; Cell surface; Cells; Chemotaxis; Complement; Complex; Crystallography; Cues; Data; Development; Diffuse; Diffusion; Disease; Endothelial Cells; G-Protein-Coupled Receptors; Glycosaminoglycans; Heart Diseases; Homo; Immobilization; Immune response; Immune system; Immunologic Surveillance; In Vitro; Infection; Inflammation; Inflammatory; Intervention; Investigation; Lead; Leukocytes; Malignant Neoplasms; Mediating; Membrane; Molecular; Molecular Conformation; Multiple Sclerosis; Pathology; Pharmaceutical Preparations; Physiological; Play; Polymers; Process; Production; Proteins; Proteoglycan; Receptor Activation; Receptor Signaling; Regulation; Resolution; Rheumatoid Arthritis; Roentgen Rays; Role; Signal Pathway; Signal Transduction; Site; Specificity; Structure; Surface; Therapeutic; Tissues; cell motility; cell type; chemokine; chemokine receptor; defense response; design; flexibility; in vitro Assay; in vivo; insight; interest; leukocyte activation; leukocyte homing; member; migration; monomer; mutant; novel; prevent; public health relevance; receptor; receptor binding; seven-transmembrane G-protein-coupled receptor; trafficking; transcytosis

DESCRIPTION (provided by applicant): Chemokines and their receptor are best known for their role in immune surveillance, where they control the migration and activation of leukocytes to resolve physiological abnormalities such as infection and cancer. However, inappropriate regulation of these proteins is associated with an extraordinary number of pathologies including inflammatory disease, atherosclerosis, cancer and AIDS. Thus there is significant interest in understanding how they function in order to develop drugs to block their activities. In recent years, it has become clear that chemokine-induced cell migration is a complex multistep process involving many different interactions, not only of chemokines with chemokine receptors, but also with glycosaminoglycans (GAGs) and with each other through homo- and hetero-oligomerization. GAGs are structurally diverse linear carbohydrates that are often attached to membrane bound protein anchors as proteoglycans. These interactions are involved in locally sequestering chemokines on cell surfaces, preventing diffusion so that chemokines provide directional cues for migrating cells. Other roles for chemokine:GAG interactions include transport across cells, regulation of oligomerization with as yet poorly characterized signaling consequences, and regulation of receptor binding and activation. Since GAG structures are highly diverse, interactions with chemokines may significantly contribute to the specificity and fine tuning of cell migration, well beyond the chemokine:receptor interaction. However, at present, there is little structural information about chemokine:GAG complexes and their precise functional consequences. An overarching hypothesis of this proposal, is that structural plasticity through oligomerization of chemokines on GAGs, or GAG-induced folding of unstructured domains, are mechanisms of functional specificity/diversity, and that through changes in oligomerization or unfolded state structure, a given chemokine may recognize different GAGs. A second hypothesis is that some chemokines dynamically change their structures through homo- and hetero-oligomerization which may control other steps in cell migration in addition to immobilization on GAGs. Aim 1 involves structural studies of chemokine:GAG complexes to (i) identify GAGs that preferentially recognize specific chemokines and determine the level of specificity; (ii) characterize binding affinities and interaction mechanisms (e.g. oligomerization or folding of unstructured domains); and (iii) determine trans-scale structural information of complexes from small oligomers through larger oligomeric assemblies on flexible GAGs. To complement these studies, in Aim 2, structural information will be correlated with function to probe how dynamic changes in chemokine oligomerization and GAG interactions coordinate discrete sequential steps of cell migration: (i) transcytosis and cell surface presentation on GAGs, (ii) leukocyte arrest (iii) transmigration, and (iv) activation of cellular defense responses. Together these studies will provide novel insight into the regulation of chemokine function through GAG- binding and oligomerization, where structural plasticity is likely to play a significant role.

描述(申请人提供)：趋化因子及其受体以其在免疫监测中的作用而闻名，在免疫监测中，它们控制白细胞的迁移和激活，以解决诸如感染和癌症等生理异常。然而，这些蛋白的不适当调控与许多病理疾病有关，包括炎症性疾病、动脉粥样硬化、癌症和艾滋病。因此，人们非常有兴趣了解它们是如何发挥作用的，以便开发药物来阻断它们的活动。近年来发现，趋化因子诱导的细胞迁移是一个复杂的多步骤过程，不仅涉及趋化因子与趋化因子受体的相互作用，还涉及趋化因子与糖胺聚糖(GAG)的相互作用，以及通过同源和异源齐聚相互作用。GAG是一种结构多样的线性碳水化合物，通常以蛋白多糖的形式附着在膜结合的蛋白质锚上。这些相互作用涉及将趋化因子局部隔离在细胞表面，防止扩散，从而使趋化因子为细胞迁移提供定向线索。趋化因子的其他作用：GAG相互作用包括跨细胞运输，调节寡聚作用，目前尚不清楚的信号后果，以及调节受体结合和激活。由于GAG结构高度多样化，与趋化因子的相互作用可能对细胞迁移的特异性和微调做出重大贡献，远远超出趋化因子：受体相互作用。然而，目前关于趋化因子：GAG复合体及其确切的功能结果的结构信息很少。这一建议的一个重要假设是，通过GAG上趋化因子的寡聚或由GAG诱导的非结构结构域的折叠而产生的结构可塑性是功能特异性/多样性的机制，并且通过寡聚或未折叠状态结构的变化，给定的趋化因子可能识别不同的GAG。第二种假设认为，一些趋化因子通过同源和异源齐聚作用动态改变其结构，这可能控制细胞迁移的其他步骤，除了固定在GAG上。目标1涉及趋化因子的结构研究：GAG复合体，以(I)识别优先识别特定趋化因子的GAG并确定特异性水平；(Ii)表征结合亲和力和相互作用机制(例如，非结构结构域的寡聚或折叠)；以及(Iii)确定从小寡聚到柔性GAG上的较大寡聚组装的复合体的跨尺度结构信息。为了补充这些研究，在目标2中，结构信息将与功能相关，以探索趋化因子寡聚和GAG相互作用的动态变化如何协调细胞迁移的离散顺序步骤：(I)跨细胞和细胞表面呈现在GAG上，(Ii)白细胞停滞(Iii)迁移，以及(Iv)激活细胞防御反应。总之，这些研究将为通过Gag结合和寡聚调节趋化因子功能提供新的见解，其中结构可塑性可能发挥重要作用。