Molecular and genetic analysis of CDK-5 function in synaptic transmission

描述（由申请人提供）：本研究的长期目标是识别和了解调节CDK-5在突触传递中的功能的基因和机制。细胞周期蛋白依赖性激酶CDK-5在发育过程中具有多种细胞功能，参与多种神经退行性疾病，最近被认为是突触功能和可塑性的重要调节因子。本提案的重点是研究CDK-5调节谷氨酸受体（GluR）运输的机制，并确定控制CDK-5在突触上功能的上游调节信号。突触GluRs的定位和丰富程度的活动依赖性调节直接影响突触强度，并被认为是大脑信息存储和处理的基础。GluRs的异常调节可能导致缺血（缺乏血流）、中风和神经退行性疾病的兴奋性毒性。因此，确定调节GluR转运的基本细胞生物学机制是很重要的。我们使用秀丽隐杆线虫作为遗传模型来研究体内调节突触传递和谷氨酰胺转运的基因和机制。秀丽隐杆线虫的优势包括紧凑的基因组（即较少的基因冗余），强大的遗传工具以及动物耐受神经系统功能严重下降的能力。我们的初步研究表明，CDK-5在体内调节突触上支架蛋白LIN-10/Mint-1和谷氨酸受体GLR-1的丰度。LIN-10/Mint-1是一种含有PTB和PDZ结构域的蛋白，定位于高尔基体和突触，在神经元和上皮的极化转运中起保守作用。在本提案中，我们将(1)确定CDK-5调控GLR-1贩运的哪一步，(2)定义CDK-5调控LIN-1u/Mint-1丰度的机制，(3)表征控制CDK-5功能的上游调控信号。这项研究可能为控制脑卒中和缺血性脑损伤后glur介导的兴奋性毒性的治疗干预提供新的靶点。此外，由于CDK-5调节神经元的发育和功能，并参与阿尔茨海默病和肌萎缩侧索硬化症（ALS），了解CDK-5活性的调节机制及其如何控制健康神经元的突触传递将有助于揭示CDK-5在神经变性中作用的发病机制。

DESCRIPTION (provided by applicant): The long-term goal of this research is to identify and understand the genes and mechanisms that regulate CDK-5 function in synaptic transmission. The cyclin-dependent kinase CDK-5 has diverse cellular functions during development, contributes to several neurodegenerative disorders, and has recently emerged as an important regulator of synapse function and plasticity. The focus of this proposal is to investigate the mechanisms by which CDK-5 regulates glutamate receptor (GluR) trafficking and to identify upstream regulatory signals that control CDK-5 function at the synapse. Activity-dependent regulation of the localization and abundance of synaptic GluRs directly affects synaptic strength and is thought to underlie information storage and processing in the brain. Aberrant regulation of GluRs may contribute to excitotoxicity in ischemia (lack of blood flow), stroke and neurodegenerative disorders. Thus, it is important to define the basic cell biological mechanisms that regulate GluR transport. We use C. elegans as a genetic model to study the genes and mechanisms that regulate synaptic transmission and GluR trafficking in vivo. Advantages of C. elegans include the compact genome (i.e. less gene redundancy), powerful genetic tools and ability of the animal to tolerate severe reductions in nervous system function. Our preliminary studies indicate that CDK-5 regulates the abundance of the scaffolding protein LIN-10/Mint-1 and the glutamate receptor GLR-1 at synapses in vivo. LIN-10/Mint-1 is a PTB and PDZ domain-containing protein that has been localized to the golgi and synapses and has a conserved role in polarized transport in neurons and epithelia. In this proposal, we will (1) Determine which step of GLR-1 trafficking is regulated by CDK-5, (2) Define the mechanisms by which CDK-5 regulates the abundance of LIN-1u/Mint-1, (3) Characterize the upstream regulatory signals that control CDK-5 function. This research may reveal novel targets for therapeutic intervention to control GluR-mediated excitotoxicity after stroke and ischemic (lack of blood flow) brain injury. In addition, since CDK-5 regulates neuronal development and function, and contributes to Alzheimer's Disease and amyotrophic lateral sclerosis (ALS), understanding the mechanisms that regulate CDK-5 activity and how it controls synaptic transmission in healthy neurons will help reveal the pathogenesis underlying the role of CDK-5 in neurodegeneration.