Mechanisms of receptor protein tyrosine phosphatase signaling in Drosophila devel

果蝇发育中受体蛋白酪氨酸磷酸酶信号传导机制

• 批准号: 7983798
• 负责人: Jessica E Treisman
• 金额: $ 31.72万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7983798
• 关键词: Active Sites; Address; Amino Acids; Axon; Binding; Biochemical; Biological Models; Brain; Cadherins; Cell surface; Cell-Cell Adhesion; Cell-Matrix Junction; Cells; Collection; Data; Developmental Process; Diabetes Mellitus; Dimerization; Disease; Drosophila genus; Drug Design; Extracellular Domain; Family; Functional disorder; Genes; Genetic; Genetic screening method; Growth; HLA Antigens; Heparan Sulfate Proteoglycan; Heterodimerization; Homeostasis; Homodimerization; Homologous Gene; Human; Human Development; Integrins; Ligands; Malignant Neoplasms; Mediating; Metabolic; Metabolism; Methods; Motor Neurons; Muscle; Mutation; Natural regeneration; Neuromuscular Junction; Neurons; Non-Insulin-Dependent Diabetes Mellitus; Organism; Parkinson Disease; Pathway interactions; Phenotype; Phosphoric Monoester Hydrolases; Photoreceptors; Play; Process; Property; Protein Tyrosine Phosphatase; Proteins; RNA Interference; Receptor Signaling; Regulation; Restless Legs Syndrome; Role; Signal Transduction; Signaling Molecule; Speed; Synapses; System; Testing; Transgenic Organisms; Ulcerative Colitis; axon growth; cancer type; carcinogenesis; extracellular; human PTPRT protein; human disease; in vivo; member; mutant; nervous system development; neuromuscular; neuron development; novel; public health relevance; receptor; research study; syndecan; tool

DESCRIPTION (provided by applicant): Receptor protein tyrosine phosphatases (RPTPs) have important functions in nervous system development and are implicated in metabolic regulation and carcinogenesis. However, many questions remain regarding their regulation by extracellular ligands and their downstream signaling mechanisms. The fruit fly Drosophila offers an attractive model system in which to address the mechanisms of RPTP function in vivo. LAR and PTP69D, the two Drosophila members of the type IIa family of RPTPs, are required for R7 photoreceptors to select the correct synaptic target layer, and for larval motor neurons to form synapses of the correct size on their target muscles. Mutation of either RPTP produces a strong and quantifiable phenotype. However, R7 photoreceptors and larval motor neurons differ significantly in their requirements for specific structural features of LAR. This proposal will investigate how the novel signaling mechanism used by LAR to direct R7 targeting differs from its mode of action in motor neuron synapse growth and from PTP69D signaling. The phosphatase activity of some RPTPs is negatively regulated by dimerization. Preliminary data shows that R7 target selection does not require the phosphatase activity of LAR, but does require a domain that mediates LAR dimerization. The first aim of this proposal will examine whether PTP69D also has two distinct signaling mechanisms, and whether it is interchangeable with LAR in motor neurons. It will also study the effect of forced dimerization on LAR function and develop a method to visualize LAR dimerization in vivo. In addition, the importance of PTP69D homodimerization or heterodimerization with LAR will be investigated. RPTPs have been shown to regulate both cell-cell and cell-matrix adhesion. In the second aim of this proposal, molecules implicated in each of these functions will be tested for genetic and physical interactions with LAR to determine whether the phosphatase-independent function of LAR in R7 photoreceptors uses one of these mechanisms. In addition, both genetic and biochemical methods will be used in unbiased screens for potentially novel molecules that require the dimerization domain to interact with LAR and might therefore act downstream of LAR in R7. The ligands that control LAR activity in motor neurons do not regulate it in R7. The final aim of this proposal is to screen transmembrane and secreted proteins for an effect on R7 targeting, in order to identify candidate ligands for LAR or PTP69D expressed by the target neurons. These candidates will then be tested for their ability to bind to and regulate the function of both RPTPs. Taken together, the experiments in this proposal will characterize a non-canonical mechanism of RPTP function, and may identify new ligands and downstream effectors for this important but poorly understood class of receptors. PUBLIC HEALTH RELEVANCE: Mammalian receptor tyrosine phosphatases of the type IIa family are essential for normal neuronal development and regeneration, as well as for metabolic homeostasis; however, the mechanisms by which these receptors signal are not well understood. We have found that one such receptor signals through distinct mechanisms in two different developmental processes; using Drosophila, a model system that offers advantages such as powerful genetic tools, speed, and economy, we will characterize the novel mechanism. Evolutionary conservation of the components suggests that our results will be applicable to higher organisms, and may guide drug design to treat human diseases caused by receptor tyrosine phosphatase dysfunction such as cancer, diabetes and ulcerative colitis.

描述（由申请人提供）：受体蛋白酪氨酸磷酸酶（RPTP）在神经系统发育中具有重要功能，并且与代谢调节和致癌作用有关。然而，关于细胞外配体的调节及其下游信号传导机制仍然存在许多问题。果蝇提供了一个有吸引力的模型系统，可用于研究 RPTP 体内功能的机制。 LAR 和 PTP69D 是 IIa 型 RPTP 家族的两个果蝇成员，是 R7 光感受器选择正确突触目标层以及幼虫运动神经元在目标肌肉上形成正确大小突触所必需的。任一 RPTP 的突变都会产生强烈且可量化的表型。然而，R7 光感受器和幼虫运动神经元对 LAR 特定结构特征的要求存在显着差异。该提案将研究 LAR 用于指导 R7 靶向的新型信号传导机制与其在运动神经元突触生长中的作用模式以及 PTP69D 信号传导有何不同。 一些 RPTP 的磷酸酶活性受到二聚化的负调节。初步数据表明，R7靶点选择不需要LAR的磷酸酶活性，但确实需要介导LAR二聚化的结构域。该提案的第一个目标是检查 PTP69D 是否也具有两种不同的信号传导机制，以及它是否可以与运动神经元中的 LAR 互换。它还将研究强制二聚化对 LAR 功能的影响，并开发一种体内可视化 LAR 二聚化的方法。此外，还将研究 PTP69D 同二聚化或与 LAR 异二聚化的重要性。 RPTP 已被证明可以调节细胞-细胞和细胞-基质粘附。在该提案的第二个目标中，将测试涉及这些功能的分子与 LAR 的遗传和物理相互作用，以确定 R7 光感受器中 LAR 的磷酸酶独立功能是否使用这些机制之一。此外，遗传和生化方法将用于无偏筛选潜在的新型分子，这些分子需要二聚化结构域与 LAR 相互作用，因此可能在 R7 中作用于 LAR 的下游。 控制运动神经元中 LAR 活性的配体并不调节 R7 中的 LAR 活性。该提案的最终目的是筛选跨膜蛋白和分泌蛋白对 R7 靶向的影响，以确定靶神经元表达的 LAR 或 PTP69D 的候选配体。然后将测试这些候选者结合和调节两个 RPTP 功能的能力。总而言之，本提案中的实验将表征 RPTP 功能的非典型机制，并可能为这一重要但知之甚少的受体类别识别新的配体和下游效应器。 公共卫生相关性：IIa 型家族的哺乳动物受体酪氨酸磷酸酶对于正常神经元发育和再生以及代谢稳态至关重要；然而，这些受体发出信号的机制尚不清楚。我们发现，一种这样的受体在两种不同的发育过程中通过不同的机制发出信号；果蝇是一种模型系统，具有强大的遗传工具、速度和经济性等优势，我们将利用果蝇来表征这种新机制。这些成分的进化保守性表明我们的结果将适用于高等生物，并可能指导药物设计来治疗由受体酪氨酸磷酸酶功能障碍引起的人类疾病，例如癌症、糖尿病和溃疡性结肠炎。