RGS14 Regulation of Hormone-sensitive NPT2A-mediated Phosphate Transport

RGS14 激素敏感 NPT2A 介导的磷酸盐转运的调节

• 批准号: 10450178
• 负责人: Peter A Friedman
• 金额: $ 45.66万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10450178
• 关键词: Affect; Attenuated; Back; Binding; Biotin; Brain; C-terminal; Cells; Chronic Kidney Failure; Code; Complex; Cyclic AMP; Data; Disease; Dissociation; Elements; Epithelial Cells; Equilibrium; Exhibits; FGFR1 gene; G-Protein-Coupled Receptors; GTP Binding; GTP-Binding Proteins; Goals; Heart; Hippocampus (Brain); Hormones; Human; Human Cell Line; Kidney; Kidney Diseases; Learning; Ligands; Ligase; Link; MAP Kinase Gene; MAPK Signaling Pathway Pathway; Mediating; Metabolism; Modeling; Molecular; Mus; Mutation; Osteopenia; Outcome; PDZ protein; PTH gene; Patients; Phosphorylation; Phosphotransferases; Prevalence; Proteins; Proteomics; Proximal Kidney Tubules; Regulation; Rodent; Role; Scaffolding Protein; Secondary Hyperparathyroidism; Serum; Signal Pathway; Signal Transduction; Site; Small Interfering RNA; Synaptic plasticity; Tertiary Protein Structure; Testing; Tissues; Ventricular Remodeling; base; clinically relevant; genome wide association study; hormone regulation; inorganic phosphate; insight; knock-down; novel; response; scaffold; uptake

PROJECT SUMMARY: PTH and FGF23 initiate signaling pathways in renal proximal tubule cells that converge on the [NPT2A:NHERF1] complex to inhibit phosphate uptake. Mice lacking the PDZ protein NHERF1 and humans harboring NHERF1 mutations are hypophosphatemic. Important gaps exist in understanding the elements involved in these actions due to unidentified factors. Numerous GWAS studies of patients with chronic kidney disease implicate RGS14, which harbors a PDZ-recognition motif. We propose that RGS14 is a novel regulator of hormone-sensitive phosphate transport, and provide preliminary data to support this idea. RGS14 is scaffold that integrates G protein, MAPK, and Ca++/CaM signaling pathways. Its actions are best understood in rodent brain, where RGS14 suppresses synaptic plasticity and hippocampal-based learning. Nothing is known about RGS14 effects on hormone action or in kidney. Our preliminary findings show that RGS14 suppresses both PTH- and FGF23-regulated phosphate transport. RGS14 persistently attenuates PTH-regulated phosphate transport in primary human proximal tubule cells. RGS14 knock-down by siRNA reverses this action to reveal full PTH activity. RGS14 add-back to cells lacking the protein blocks PTH actions. Human RGS14 contains a C- terminal PDZ ligand (-DSAL) that directly binds NHERF1. Mutations in the PDZ-ligand disrupt RGS14 binding to NHERF1 and interfere with RGS14 regulation of hormone actions. These findings identify RGS14 as an entirely new element regulating hormone action on a vital homeostatic activity, and raise the hypothesis that RGS14 is a novel regulator of hormone-sensitive [NPT2A:NHERF1]-mediated phosphate transport in renal proximal tubule cells. Three Aims will test this premise. AIM 1 will define how RGS14 regulates assembly, disassembly of [NPT2A:NHERF1], its internalization and hormone-sensitive phosphate uptake. AIM 2 will define the locus of RGS14 effects on PTH and FGF23 signaling and the impact of hormone-directed NHERF1 phosphorylation on RGS14 regulation of the [NPT2A:NHERF1] complex. AIM 3: will define how PTH- and FGF23-directed signaling affect RGS14 interactions with NHERF1 and the [NHERF1:NPT2A] complex. These studies will identify novel roles and molecular mechanisms by which RGS14 regulates NPT2A function and hormone-sensitive phosphate transport in kidney as related to kidney disease.

项目摘要：PTH 和 FGF23 启动汇聚的肾近端小管细胞中的信号传导通路 作用于 [NPT2A:NHERF1] 复合物以抑制磷酸盐的吸收。缺乏 PDZ 蛋白 NHERF1 的小鼠 携带 NHERF1 突变的人类患有低磷血症。在理解方面存在重要差距 由于不明因素而参与这些行动的要素。大量针对慢性病患者的 GWAS 研究 肾脏疾病涉及 RGS14，它含有 PDZ 识别基序。我们建议 RGS14 是一部小说 激素敏感的磷酸盐运输的调节剂，并提供初步数据来支持这一想法。 RGS14 是整合 G 蛋白、MAPK 和 Ca++/CaM 信号通路的支架。它的行为是最好理解的 在啮齿动物大脑中，RGS14 抑制突触可塑性和基于海马的学习。什么都不知道 关于 RGS14 对激素作用或肾脏的影响。我们的初步研究结果表明 RGS14 抑制 PTH 和 FGF23 调节磷酸盐转运。 RGS14 持续减弱 PTH 调节的磷酸盐 原代人近端小管细胞中的转运。通过 siRNA 敲除 RGS14 可逆转这一作用，揭示 完整的 PTH 活性。 RGS14 回加到缺乏该蛋白的细胞中会阻断 PTH 的作用。人类 RGS14 包含一个 C- 直接结合 NHERF1 的末端 PDZ 配体 (-DSAL)。 PDZ-配体的突变破坏了 RGS14 的结合 NHERF1 并干扰 RGS14 对激素作用的调节。这些发现将 RGS14 确定为 全新的元素调节激素对重要稳态活动的作用，并提出以下假设： RGS14 是一种新型的激素敏感 [NPT2A:NHERF1] 介导的肾近端磷酸盐转运调节剂 肾小管细胞。三个目标将检验这个前提。 AIM 1 将定义 RGS14 如何规范组装、拆卸 [NPT2A:NHERF1]，其内化和激素敏感的磷酸盐摄取。 AIM 2 将定义轨迹 RGS14 对 PTH 和 FGF23 信号传导的影响以及激素指导的 NHERF1 磷酸化对 RGS14 对 [NPT2A:NHERF1] 复合物的调节。 AIM 3：将定义 PTH 和 FGF23 定向信号传导的方式 影响 RGS14 与 NHERF1 和 [NHERF1:NPT2A] 复合物的相互作用。这些研究将确定新颖的 RGS14 调节 NPT2A 功能和激素敏感磷酸盐的作用和分子机制 与肾脏疾病相关的肾脏转运。