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

• 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
• 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

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）在神经系统的神经发生、细胞增殖和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亚型的重叠功能使遗传分析变得复杂1，2，而许多RPTP的真实配体仍然未知3。最近的研究使用的模型系统Manducasexta已经确定了一个新的功能，一个特定的RPTP，可以澄清这些问题。在发育中的Manduca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，在此期间它们在预先形成的肌带通路上行进，同时避开肠中线。先前的工作表明，中线肌肉表达该系统中唯一的Eph受体酪氨酸激酶（MsEph），而成神经细胞表达其同源Ephrin配体（MsEphrin; GPI连接或A型Ephrin）4。有趣的是，通过MsEphrin的“反向”信号传导防止成神经细胞穿过MsEph表达的中线细胞，这是一种涉及Src家族激酶（SFK）的局部激活和其前导过程的收缩的反应5，6。相比之下，通过MsEph受体的常规“正向”信号传导在此过程中不起作用，提供了Ephrin-A反向信号传导在成神经细胞定位控制中的第一个例子。然而，GPI连接的Ephrin跨膜传递信号的机制仍然知之甚少。MsEphrin共受体的亲和筛选鉴定了PTP 10 D，一种调节CNS 2中线轴突反应的“III型”RPTP。初步研究表明，成神经细胞共表达PTP 10 D和MsEphrin，而抑制PTP 10 D表达诱导了与阻断MsEphrin信号传导所引起的异位中线交叉相同的模式。有趣的是，PDZ衔接蛋白ZO-1（闭锁小带-1）也在该筛选中被鉴定，并显示与MsEphrin和PTP 10 D在成神经细胞中共定位。ZO-1最初被分类为紧密连接蛋白7，也可以在体外调节细胞迁移8，9， 在各种情况下与RPTP和SFK相互作用10 -12。这个建议的总体目标是确定PTP 10 D如何调节神经母细胞迁移在发展中的ENS。中心假设是，PTP 10 D作为一个共同受体MsEphrin，耦合这个GPI连接的Ephrin与ZO-1及其下游效应。具体目标将测试PTP 10 D和ZO-1在MsEphrin依赖性迁移方面的作用，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R 01应用提供重要的新数据，目标是全面定义Ephrin-A在神经系统中的反向信号传导机制。公共卫生相关性：证明RPTP和Z 0 -1在Ephrin-A信号传导中的新作用将为研究为什么影响Ephrin-A的人突变导致缺陷性脑生长13和开发解决其中Ephrin-A反向信号传导可能被错误调节的神经退行性病症的新治疗策略14 -16提供新的工具。