Axon Transport of TrkA receptors in sympathetic neurons

交感神经元中 TrkA 受体的轴突运输

• 批准号: 10189732
• 负责人: Blaine Connor
• 金额: $ 3.1万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10189732
• 关键词: Anabolism; Antibodies; Apoptosis; Axon; Axonal Transport; Binding; Binding Proteins; Biochemical; Biological Assay; Biological Process; Biotin; Cardiac Output; Cells; Communication; Complex; Confocal Microscopy; Diffuse; Endocytosis; Event; Family; Fellowship; Goals; Growth Factor; Homeostasis; Image; Knock-in; Knock-in Mouse; Label; Leadership; Ligands; Mediating; Membrane Proteins; Mentors; Methods; Monitor; Morphology; Mus; Mutate; Nerve Growth Factor Receptors; Nerve Growth Factors; Nerve Regeneration; Nervous system structure; Neurons; Neurotrophic Tyrosine Kinase Receptor Type 1; Nuclear; Organ; Pathway interactions; Peripheral; Phosphoric Monoester Hydrolases; Phosphotransferases; Physiologic Thermoregulation; Physiological; Physiological Processes; Point Mutation; Presynaptic Terminals; Process; Protein Tyrosine Kinase; Protein Tyrosine Phosphatase; Proteins; Receptor Protein-Tyrosine Kinases; Receptor Signaling; Reporting; Research; Research Personnel; Resources; Role; Route; Signal Transduction; Site; Sorting - Cell Movement; Surface; Synapses; Synaptic Transmission; Testing; Tissues; Training; TrkA protein; Tropomyosin; Tyrosine; Universities; anterograde transport; axon growth; base; blood glucose regulation; feeding; immune function; in vivo; meter; millimeter; mouse model; mutant; nerve supply; neurodevelopment; neuron development; neuronal cell body; neurotrophic factor; polarized cell; prevent; protein tyrosine phosphatase 1B; receptor; receptor internalization; recruit; response; retrograde transport; skills; synaptic function; trafficking; transcytosis

Project Summary/Abstract Axons of sympathetic neurons extend millimeters to meters to innervate peripheral tissues and organs, which is essential for tissue homeostasis and fundamental physiological processes including cardiac output, body temperature, regulation of blood glucose levels, and immune functions. Target-derived signals, such as the neurotrophin, Nerve Growth Factor (NGF), recruit growing axons by binding to TrkA receptors located on axon terminals, to initiate local and long-range retrograde signaling events to support neuron development, maturation, and synaptic functions. To sustain functional responses to target derived ligand, TrkA receptors must be continually localized to axon terminals. Yet, how TrkA receptors are delivered to axons remains largely undefined. Previously, we reported that TrkA receptors are delivered to sympathetic axons by transcytosis, where newly synthesized receptors are first inserted on soma surfaces, then internalized and anterogradely transported to axons. Furthermore, we identified that TrkA transcytosis is primed by the activity of PTP1B, an ER-resident protein tyrosine phosphatase, in cell bodies. The overall goal of my thesis project and this application is to test the hypothesis that PTP1B phosphatase promotes a gain of TrkA biological function by controlling the long- distance transcytosis of receptors. I will employ imaging, biochemical, and functional analyses in compartmentalized neuron cultures in combination with in vivo analyses of genetically modified mice to accomplish these goals. Specifically, I have generated a new mouse model, TrkAR685A knock-in mice, where a point mutation in TrkA prevents PTP1B binding, which will allow me to test the functional relevance of TrkA- PTP1B interactions on TrkA localization, neuron survival, and axon innervation of target tissues. Through this fellowship application, I will develop a basic understanding of the mechanisms of Trk receptor delivery to axons, and how this contributes to neuronal development. I will also develop the technical, communication, and leadership skills necessary to accomplish my goal of becoming an independent investigator. My training will be facilitated by the rigorous research plan, the expertise and guidance of my mentor and thesis committee, and the outstanding training resources and facilities available through Johns Hopkins University.

项目概要/摘要 交感神经元的轴突延伸数毫米至数米，支配周围组织和器官， 对于组织稳态和基本生理过程（包括心输出量、身体 温度、血糖水平的调节和免疫功能。目标衍生信号，例如 神经营养蛋白、神经生长因子 (NGF) 通过与轴突上的 TrkA 受体结合来募集正在生长的轴突 终端，启动局部和远程逆行信号事件以支持神经元发育、成熟、 和突触功能。为了维持对靶标衍生配体的功能反应，TrkA 受体必须 不断定位于轴突末端。然而，TrkA 受体如何传递到轴突仍然很大程度上取决于 不明确的。 之前，我们报道了 TrkA 受体通过转胞吞作用传递到交感神经轴突，其中新近 合成的受体首先插入体细胞表面，然后内化并顺行转运至 轴突。此外，我们还发现 TrkA 转胞吞作用是由 PTP1B 的活性引发的，PTP1B 是一种 ER 驻留蛋白。 细胞体内的蛋白质酪氨酸磷酸酶。我的论文项目和这个应用程序的总体目标是测试 PTP1B 磷酸酶通过控制长链来促进 TrkA 生物学功能的获得的假设 受体的距离转胞吞作用。我将采用成像、生化和功能分析 区室化神经元培养与转基因小鼠的体内分析相结合 实现这些目标。具体来说，我生成了一个新的小鼠模型，TrkAR685A 敲入小鼠，其中 TrkA 中的点突变阻止了 PTP1B 结合，这将使我能够测试 TrkA 的功能相关性 PTP1B 对 TrkA 定位、神经元存活和靶组织轴突神经支配的相互作用。通过这个 奖学金申请，我将对 Trk 受体传递到轴突的机制有一个基本的了解， 以及这如何有助于神经元发育。我还将开发技术、沟通和 实现我成为独立调查员的目标所必需的领导技能。我的训练将是 得益于严格的研究计划、我的导师和论文委员会的专业知识和指导，以及 约翰·霍普金斯大学提供出色的培训资源和设施。