RECEPTOR TYROSINE PHOSPHATASES IN THE GROWTH OF AXONS

描述(从申请人摘要逐字摘录)：规则 酪氨酸激酶的磷酸化对肿瘤的生长和导向至关重要 轴突。有证据表明，CAM样受体-酪氨酸磷酸酶 (RPTPs)在轴突生长的信号传递过程中起着关键作用。这 项目测试了一种假设，即RPTPs，表达在发育过程的表面 神经元在胚胎发育过程中通过结合轴突来调节轴突生长。 它们的胞外区有特定的配体。这里的重点是2 特定的RPTP--CRYP-2和PTP-deltadelta--是很好的候选者 参与轴突生长的调节。牵涉到这些的证据 两个RPTPs包括结构、表达模式和初步分析 在体外发挥作用。关于这些RPTP的主要问题是：什么是 CRYP-2和PTP-Delta的调节配体？以及CRYP-2和PTP-Delta的情况如何 参与轴突生长吗？这些问题将通过相互关联来解决 CRYP-2和PTP-Delta的配体表达与RPTPs的表达 自身，这些配体的特性，以及功能的检查 CRYP-2和PTP-Delta在体外和体内轴突生长中的作用。确实有 三个具体目标。首先，RPTP的潜在监管配体将是 通过免疫沉淀、亲和层析进行定位和鉴定 和表达克隆。识别配体将允许关键的生化 这些RPTP的粘附性和信号功能的实验。第二， RPTPs的胞外结构域将被用作轴突生长的调节因子 和体外指导，在分析与此相关的机制时 监管。这些结果将提供详细的机械证据 这些RPTP是如何发挥作用的。最后，两种不同的体内检测系统 (突变的逆转录病毒表达和基因敲除)将用于评估 这些RPTPs在胚胎发育期间神经元发育中的作用。这些 化验将提供对假设的直接检验，即特定的PTP在 研究在功能上与体内轴突的生长和指导有关。建议数 实验将使这一领域更接近于分子理解 脊椎动物轴突生长的调控。这一理解对于 神经系统发育障碍的合理方法也是如此 作为脊髓再生的问题。

DESCRIPTION (Verbatim from the Applicant's Abstract): The regulation of tyrosine kinase phosphorylation is critical for the growth and guidance of axons. Evidence suggests that the CAM-like receptor-tyrosine phosphatases (RPTPs) play key roles in the signaling processes underlying axon growth. This project tests the hypothesis that RPTPs, expressed on the surface of developing neurons regulate axon growth during embryogenesis, through the binding of specific ligands to their extracellular domains. The focus here is on 2 specific RPTPs -- CRYP-2 and PTP-deltadelta -- that are excellent candidates for involvement in the regulation of axon growth. Evidence implicating these two RPTPs includes structure, expression pattern, and preliminary analysis of function in vitro. The major questions concerning these RPTPs are: What are the regulatory ligands for CRYP-2 and PTP-delta?, and How are CRYP-2 and PTP-delta involved in axon growth? These questions will be addressed through correlation of expression of ligands for CRYP-2 and PTP-delta with expression of the RPTPs themselves, characterization of these ligands, and examination of the function of CRYP-2 and PTP-delta in axon growth, both in vitro and in vivo. There are three specific aims. First, potential regulatory ligands for the RPTPs will be localized, and identified through immunoprecipitation, affinity chromatography and expression cloning. Identification of ligands will allow key biochemical experiments on adhesive and signaling functions of these RPTPs. Second, the extracellular domains of the RPTPs will be used as regulators of axon growth and guidance in vitro, in an analysis of the mechanisms involved in this regulation. These results will provide detailed mechanistic evidence concerning how these RPTPs function. Finally, two different in vivo assay systems (retroviral expression of mutants and gene knockout) will be employed to assess the role of these RPTPs in neuronal development during embryogenesis. These assays will provide direct tests of the hypothesis that the specific PTPs under study are functionally linked to axon growth and guidance in vivo. The proposed experiments will move the field closer to a molecular understanding of the regulation of vertebrate axon growth. This understanding is critical for rational approaches to developmental disorders of the nervous system, as well as the problem of spinal cord regeneration.