The function of ATM protein in the biology of the adult neuron CNS:

描述（由申请人提供）：共济失调毛细血管扩张症（A-T）是一种具有深远破坏性的儿童期疾病，由编码 PI3 激酶家族成员的基因突变引起。该基因被称为共济失调毛细血管扩张突变（ATM），是 DNA 双链断裂反应机制中公认的组成部分。然而，ATM 突变的后果包括严重的神经系统缺陷，虽然 A-T 的某些特征可以通过对 DNA 损伤的错误反应来解释，但很难在此基础上充分解释该疾病的神经系统方面。该应用的核心假设是存在一种神经系统特异性的细胞质 ATM 形式。在此位置，它充当丝氨酸-苏氨酸激酶，但同样充当伴侣蛋白，使蛋白质复合物成核，其中包括突触蛋白-I 和 VAMP2 等囊泡蛋白。我们认为，细胞质 ATM 相关功能的失败导致了 A-T 的许多神经系统症状。我们将通过两部分的策略来探讨这个假设。我们的首要目标是扩大我们对 ATM 作为神经元核细胞质蛋白的作用的理解，并揭示其双重定位所实现的独特功能。我们将探讨细胞质 ATM 本身如何促进神经元功能，以及它如何与细胞核中的对应物协调其作用。我们的结果测量将包括树突形态、突触生理学、细胞周期调节和细胞存活。我们战略的第二部分将是开发强大的临床前平台，包括体内和体外，以测试目前正在临床研究的几种药物。我们提供的初步数据表明，只要选择正确的等位基因集进行分析，人类 A-T 表型多样性就能在小鼠中成功模拟。我们将使用这个新扩展的小鼠模型视图来测试 ATM 在神经元对应激（如兴奋性毒性、DNA 损伤和氧化应激）反应中的参与情况。使用与上述相同的结果测量，我们将专门测试野生型和 Atm 缺陷细胞对应激的反应，并比较抗氧化和抗炎策略作为保护剂的效力。成功的线索之后将进行体内试验，比较野生型与两种不同的 Atm 突变及其复合杂合子。在最后一系列试点实验中，我们将探讨 ATM 故障是否在其他神经退行性疾病中发挥作用。总的来说，这些研究为与 A-T 相关的神经缺陷提供了新的视角，并通过体外和体内模型系统的开发，为发现这种破坏性病症的治疗方法带来了新的动力。 公共健康相关性：神经元细胞质中 ATM 蛋白的动态行为以及其与参与突触小泡行为的蛋白质密切相关的发现表明，共济失调毛细血管扩张的神经生物学的某些方面仍有待发现。所提出的实验将为共济失调毛细血管扩张症和其他神经系统疾病的进展带来新的见解并提供新的线索，其中阿尔茨海默病只是一个例子。因此，对这些现象的探索对于我们对大脑功能及其在许多不同临床相关情况下的功能障碍的基本生物学理解具有重要价值。

DESCRIPTION (provided by applicant): Ataxia-telangiectasia (A-T) is a profoundly destructive childhood disorder resulting from mutation of a gene encoding a member of the PI3 kinase family. The gene, named ataxia- telangiectasia mutated (ATM) is a recognized component of the response mechanism to DNA double strand breaks. Yet, the consequences of ATM mutation include dramatic neurological deficiencies, and while some features of A-T can be explained by a faulty response to DNA damage, it is hard to fully account for the neurological aspects of the disease on this basis. The core hypothesis of this application is that there is a nervous system-specific form of ATM that is cytoplasmic. In this location, it serves as a serine-threonine kinase but equally as a chaperone protein that nucleates a complex of proteins that includes vesicle proteins such as synapsin-I and VAMP2. We propose that it is the failure of the functions associated with cytoplasmic ATM that leads to many of the neurological symptoms of A-T. We will explore this hypothesis in a two-part strategy. Our first aim is to expand our understanding of the role of ATM as a nucleocytoplasmic protein in neurons, and to uncover the unique functions that are enabled by its dual localization. We will explore how cytoplasmic ATM contributes to neuronal function on its own, and how it coordinates its action with its counterpart in the nucleus. Our outcome measures will include dendritic morphology, synaptic physiology, cell cycle regulation and cell survival. The second part of our strategy will be to develop strong pre-clinical platforms, both in vivo and in vitro, to test several agents currently under study in the clinic. We provide preliminary data showing that the well-described diversity of phenotype in human A-T is mimicked successfully in the mouse, provided that the correct set of alleles is chosen for analysis. We will use this newly expanded view of the mouse models to test the involvement of ATM in the neuronal response to stresses such as excitotoxicity, DNA damage and oxidative stress. Using the same outcome measures as above we will specifically test wild type and Atm- deficient cells for their response to stress and compare anti-oxidant and anti-inflammatory strategies for the potency as protective agents. Successful leads will be followed by in vivo trials comparing wild type with two different Atm mutations and their compound heterozygote. In a final series of pilot experiments we will explore whether ATM malfunction plays a role in other neurodegenerative disease. In the aggregate these studies offer a new look at the neurological deficits associated with A-T and, through the development of in vitro and in vivo model systems, brings fresh momentum to the discovery of treatments for this devastating condition. PUBLIC HEALTH RELEVANCE: The dynamic behavior of the ATM protein in the neuronal cytoplasm and the discovery of its intimate association with proteins involved in synaptic vesicle behavior argue that there are facets of the neurobiology of ataxia-telangiectasia that remain to be discovered. The experiments proposed will bring new insights and offer fresh clues to the progress of ataxia-telangiectasia and other neurological diseases, of which Alzheimer's disease is only one example. The exploration of these phenomena will thus have significant value for our basic biological understanding of brain function as well as its malfunction in a number of different clinically relevant situations.