Structural and Functional Mechanisms of PTH-Receptor Signaling

PTH 受体信号传导的结构和功能机制

• 批准号: 9069816
• 负责人: Guillermo Alberto Calero
• 金额: $ 48.5万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9069816
• 关键词: Affinity; Animals; Arrestins; Behavior; Binding; Calcium; Cause of Death; Cell physiology; Cell surface; Cells; Complex; Crystallography; Cyclic AMP; Data; Development; Diagnostic radiologic examination; Disease; Drug Targeting; Early Endosome; Endosomes; G-Protein-Coupled Receptors; GTP-Binding Proteins; Goals; Health; Homeostasis; Hypocalcemia result; Hypoparathyroidism; Knowledge; Length; Ligand Binding; Ligands; Location; Measurement; Mediating; Minerals; Molecular; Molecular Conformation; Mus; Osteoporosis; PTH gene; Parathyroid Hormone Receptor; Production; Property; Proteins; Receptor Signaling; Regulation; Research; Resolution; Roentgen Rays; Role; Side; Signal Transduction; Structure; Testing; Thinking; United States; United States National Institutes of Health; X ray diffraction analysis; X-Ray Diffraction; analog; base; bone; bone cell; bone turnover; clinically relevant; disability; free-electron laser; hormone analog; insight; kidney cell; nanocrystal; novel therapeutic intervention; parathyroid hormone (1-34); pre-clinical; programs; receptor; receptor binding; receptor internalization; research study; response; signal processing; therapeutic target; therapy development; Affinity; Animals; Arrestins; Behavior; Binding; Calcium; Cause of Death; Cell physiology; Cell surface; Cells; Complex; Crystallography; Cyclic AMP; Data; Development; Diagnostic radiologic examination; Disease; Drug Targeting; Early Endosome; Endosomes; G-Protein-Coupled Receptors; GTP-Binding Proteins; Goals; Health; Homeostasis; Hypocalcemia result; Hypoparathyroidism; Knowledge; Length; Ligand Binding; Ligands; Location; Measurement; Mediating; Minerals; Molecular; Molecular Conformation; Mus; Osteoporosis; PTH gene; Parathyroid Hormone Receptor; Production; Property; Proteins; Receptor Signaling; Regulation; Research; Resolution; Roentgen Rays; Role; Side; Signal Transduction; Structure; Testing; Thinking; United States; United States National Institutes of Health; X ray diffraction analysis; X-Ray Diffraction; analog; base; bone; bone cell; bone turnover; clinically relevant; disability; free-electron laser; hormone analog; insight; kidney cell; nanocrystal; novel therapeutic intervention; parathyroid hormone (1-34); pre-clinical; programs; receptor; receptor binding; receptor internalization; research study; response; signal processing; therapeutic target; therapy development

DESCRIPTION (provided by applicant): The goal of this proposed research is to determine the structural and cellular basis underlying the mechanism of parathyroid hormone (PTH) receptor (PTHR) signaling. The PTHR is a major G protein-coupled receptor (GPCR) that regulates Ca2+ homeostasis and bone turnover and is the most effective therapeutic target for osteoporosis. The recently recognized capacity of PTH and certain PTH analogs to prolong G-protein activity and cAMP production after PTHR internalization into early endosomes has drastically changed how we think about cellular signaling of the PTHR, and how we study drugs that target this receptor. This new and unexpected behavior of a GPCR is of particular relevance for understanding how the recently developed long-acting PTH analogs, including LA-PTH that is in preclinical development for the treatment of hypoparathyroidism, induce remarkable prolonged signaling (cAMP and calcium) responses in cells and in mice. The structural determinants of the PTHR and cellular mechanisms responsible for these actions are not known and this is an obstacle to further progress for identifying clinically relevant analogs. We therefore propose a research program to overcome this obstacle. Two specific aims are proposed: Aim 1 determines the structural determinants of PTHR action through crystallography of full-length PTHR, and PTHR bound to PTH, or to LA-PTH. We will focus initially on the structural basis for the different functional properties of PTH ligands and on ionic interactions likely to be sensitive to pH changes encountered in endosomes because our preliminary findings support a critical role of endosomal pH on sustained PTHR signaling. This structural and molecular information will be further applied to Aim 2, which determines the cellular mechanism regulating endosomal PTHR signaling, focusing on the role of low pH conditions found in the endosome in determining the stability of PTH-PTHR-G protein complexes. Knowledge of structural details and differences of how PTH and LA-PTH bind to the PTHR and trigger signaling in specific subcellular locations (endosomes) provides insights into molecular and cellular processes, which can provide new opportunities for therapy. Selective targeting of PTHR-mediated endosomal Gs signaling might offer more effective and selective treatments than global targeting of cell-surface signaling.

描述（由申请人提供）：这项拟议的研究的目的是确定甲状旁腺激素（PTH）受体（PTHR）信号传导机理的结构和细胞基础。 PTHR是一种主要的G蛋白偶联受体（GPCR），可调节Ca2+稳态和骨转换，并且是骨质疏松症的最有效治疗靶点。 PTH和某些PTH类似物在PTHR内部化中延长G蛋白活性和cAMP生产的最近公认的能力急剧改变了我们对PTHR的细胞信号传导的看法，以及我们如何研究针对该受体的药物。 GPCR的这种新的和意想不到的行为与理解最近开发的长效PTH类似物（包括临床前开发中的LA-PTH）特别相关，该类似物是用于治疗甲状腺功能低下的抗多发性疾病，引起明显的延长信号传导（CAMP和钙）反应。 PTHR和细胞机制的结构决定因素尚不清楚，这是进一步识别临床相关类似物的进一步进展的障碍。因此，我们提出了一项研究计划来克服这一障碍。提出了两个具体的目的：AIM 1通过全长PTHR的晶体学以及与PTH或LA-PTH结合的PTHR来确定PTHR作用的结构决定因素。我们最初将重点放在PTH配体不同功能特性的结构基础上，以及可能对内体中遇到的pH变化敏感的离子相互作用，因为我们的初步发现支持内体pH值在持续PTHR信号中的关键作用。该结构和分子信息将进一步应用于AIM 2，该信息决定了调节内体PTHR信号传导的细胞机制，重点是在确定PTH-PTHR-G蛋白复合物稳定性中发现的低pH条件下的作用。在特定亚细胞位置（内体）中PTH和LA-PTH如何结合PTH和LA-PTH如何结合PTHR和触发信号传导的结构细节以及差异提供了对分子和细胞过程的见解，这可以为治疗提供新的机会。 PTHR介导的内体GS信号的选择性靶向可能比整体靶向细胞表面信号传导更有效和选择性治疗。