A novel role for receptor tyrosine phosphatase in neuroblast migration

受体酪氨酸磷酸酶在神经母细胞迁移中的新作用

基本信息

批准号：
8464388
负责人：
PHILIP F COPENHAVER
金额：
$ 22.29万
依托单位：
OREGON HEALTH & SCIENCE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-05-01 至 2015-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8464388
关键词：
Address Adult Affect Affinity Behavior Biological Assay Biological Models Brain Cell Culture Techniques Cell Proliferation Cells Co-Immunoprecipitations Complex Coupling Data Defect Degenerative Disorder Development Drosophila genus Embryo Enteral Enteric Nervous System Eph Family Receptors Ephrin B Receptor Ephrins Equilibrium Family Fluorescence Future Gene Expression Gene Mutation Gene Proteins Generations Glycosylphosphatidylinositols Goals Growth Human Immigration Injection of therapeutic agent Injury Insecta Ligands Link Manduca Manduca sexta Membrane Methods Microcephaly Modeling Molecular Mus Muscle Mutation NGFR Protein Neoplasm Metastasis Nervous system structure Neuronal Differentiation Neurons Organism Orthologous Gene Pathway interactions Pattern Play Population Positioning Attribute Preparation Process Protein Tyrosine Phosphatase Proteins Protocols documentation Publishing RNA Regulation Research Risk Role Signal Pathway Signal Transduction Staging System Testing Tight Junctions Travel Venus Work adapter protein cell motility embryo culture genetic analysis in vivo injured knock-down migration muscle form nerve stem cell nervous system disorder neuroblast neurodevelopment neurogenesis novel novel therapeutics prevent receptor response src-Family Kinases tool transcriptional coactivator p75 tyrosine receptor

项目摘要

DESCRIPTION (provided by applicant): Receptor tyrosine phosphatases (RPTPs) play important roles during neurogenesis, cell proliferation, and ne ronal positioning in the nervous system, but their mechanisms of action remain poorly understood. Genetic analyses have been complicated by the overlapping functions of different RPTP subtypes1, 2, while authentic ligands for many RPTPs remain unknown3. Recent studies using the model system Manduca sexta have identified a novel function for a specific RPTP that may clarify these issues. In the developing enteric nervous sy tem (ENS) of Manduca, placode-derived neuroblasts must migrate extensively before differentiating into ma- ture neurons, during which they travel on pre-formed muscle band pathways while avoiding the enteric midline. Previous work showed that the midline muscles express the sole Eph receptor tyrosine kinase in this system (MsEph), while the neuroblasts express its cognate Ephrin ligand (MsEphrin; a GPI-linked or type-A Ephrin)4. Intriguingly, "reverse" signaling via MsEphrin prevents the neuroblasts from crossing the MsEph-expressing midline cells, a response that involves the local activation of a Src family kinase (SFK) and retraction of their leading processes5, 6. In contrast, conventional "forward" signaling via MsEph receptors plays no role in this process, providing the first example of Ephrin-A reverse signaling in the control of neuroblast positioning. However, the mechanisms by which GPI-linked Ephrins transduce signals across the membrane remain poorly understood. An affinity screen for MsEphrin co-receptors identified PTP10D, a "type-III" RPTP that regulates midline axonal responses in the CNS2. Preliminary studies showed that PTP10D is co-expressed with MsEph- rin by the neuroblasts, while inhibiting PTP10D expression induced the same pattern of ectopic midline cros- sovers caused by blocking MsEphrin signaling. Intriguingly, the PDZ adapter protein ZO-1 (zonula occludens- 1) was also identified in this screen, and shown to co-localize with MsEphrin and PTP10D in the neuroblasts. Originally classified as a tight junction protein7, ZO-1 can also regulate cell migration in vitro8, 9 and may interact with RPTPs and SFKs in a variety of contexts10-12. The overall objective of this proposal is to determine how PTP10D regulates neuroblast migration in the developing ENS. The central hypothesis is that PTP10D acts as a co-receptor for MsEphrin, coupling this GPI-linked Ephrin with ZO-1 and its downstream effectors. Specific aims will test the role of PTP10D and ZO-1 in MsEphrin-dependent aspects of migration, using published methods to manipulate gene expression and protein interactions in embryo culture. These studies will provide essential new data for an R01 application, with the goal of comprehensively defining the mechanisms of Ephrin-A reverse signaling in the nervous system. Public Heath Relevance: Demonstrating novel roles for RPTPs and ZO-1 in Ephrin-A signaling will provide new tools for investigating why human mutations that affect Ephrin-As result in defective brain growth13, and for developing new therapeutic strategies that address neuro- degenerative conditions in which Ephrin-A reverse signaling may be misregulated14-16.

描述（由申请人提供）：受体酪氨酸磷酸酶（RPTP）在神经发生、细胞增殖和神经系统中神经元定位过程中发挥重要作用，但其作用机制仍知之甚少。不同 RPTP 亚型 1、2 的重叠功能使遗传分析变得复杂，而许多 RPTP 的真实配体仍然未知 3。最近使用 Manduca sexta 模型系统的研究已经确定了特定 RPTP 的一个新功能，可以澄清这些问题。在天蛾正在发育的肠神经系统（ENS）中，基板来源的神经母细胞在分化为成熟神经元之前必须广泛迁移，在此期间它们沿着预先形成的肌带路径行进，同时避开肠中线。先前的研究表明，中线肌肉表达该系统中唯一的 Eph 受体酪氨酸激酶 (MsEph)，而神经母细胞表达其同源 Ephrin 配体 (MsEphrin；一种 GPI 连接或 A 型 Ephrin)4。有趣的是，通过 MsEphrin 的“反向”信号传导可防止神经母细胞穿过表达 MsEph 的中线细胞，这种反应涉及 Src 家族激酶 (SFK) 的局部激活和其主导过程的回缩 5、6。相比之下，传统的“正向”信号传导通过 MsEph 受体的信号传导在此过程中不起作用，这提供了 Ephrin-A 反向信号传导在神经母细胞定位控制中的第一个例子。然而，GPI 连接的肝配蛋白跨膜转导信号的机制仍知之甚少。 MsEphrin 辅助受体的亲和力筛选鉴定出 PTP10D，这是一种调节 CNS2 中线轴突反应的“III 型”RPTP。初步研究表明，神经母细胞中 PTP10D 与 MsEphrin 共表达，而抑制 PTP10D 表达会诱导与阻断 MsEphrin 信号传导引起的相同模式的异位中线交叉。有趣的是，PDZ 接头蛋白 ZO-1（闭合小带-1）也在该筛选中被鉴定出来，并显示与 MsEphrin 和 PTP10D 在神经母细胞中共定位。 ZO-1 最初被归类为紧密连接蛋白7，也可以在体外调节细胞迁移8, 9，并且可能在各种环境中与 RPTP 和 SFK 进行交互10-12。该提案的总体目标是确定 PTP10D 如何调节发育中的 ENS 中的神经母细胞迁移。中心假设是 PTP10D 作为 MsEphrin 的共同受体，将这种 GPI 连接的 Ephrin 与 ZO-1 及其下游效应器耦合。具体目标将测试 PTP10D 和 ZO-1 在 MsEphrin 依赖的迁移方面的作用，使用已发表的方法来操纵胚胎培养中的基因表达和蛋白质相互作用。这些研究将为 R01 应用提供重要的新数据，目标是全面定义神经系统中 Ephrin-A 反向信号传导的机制。公共卫生相关性：证明 RPTP 和 ZO-1 在 Ephrin-A 信号传导中的新作用将为研究影响 Ephrin-A 的人类突变为何导致大脑生长缺陷13提供新工具，并为开发解决神经退行性疾病的新治疗策略提供新工具。其中Ephrin-A反向信号传导可能被错误调节14-16。