The role of Usp 14 in regulating neuronal function

Usp 14在调节神经元功能中的作用

基本信息

批准号：
8206680
负责人：
Scott Michael Wilson
金额：
$ 31.41万
依托单位：
UNIVERSITY OF ALABAMA AT BIRMINGHAM
依托单位国家：
美国
项目类别：
财政年份：
2004
资助国家：
美国
起止时间：
2004-01-01 至 2014-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8206680
关键词：
Acute Address Affect Age Amyotrophic Lateral Sclerosis Axon Behavioral Biochemistry Cell Culture Techniques Cells Cessation of life Chronic Cues Data Defect Deubiquitinating Enzyme Deubiquitination Development Disease Ensure Genetic Hydrolase Hydrolysis Lead Limb structure MAP Kinase Gene Maintenance Motor Motor Endplate Motor Neuron Disease Motor Neurons Mus Mutation Nerve Nervous system structure Neurologic Neuromuscular Diseases Neuromuscular Junction Neurons Pathogenesis Pathology Pathway interactions Phenotype Phosphotransferases Presynaptic Terminals Process Proteins Publishing Recycling Regulation Reporting Research Rest Tremor Role Series Signal Pathway Signal Transduction Site Sodium Channel Spinal Muscular Atrophy Synapses Synaptic Transmission System Testing Therapeutic Intervention Transgenes Transgenic Mice Transgenic Organisms Ubiquitin Work Yeasts design effective therapy in vivo inhibitor/antagonist insight motor neuron development motor neuron function mouse model multicatalytic endopeptidase complex muscle form mutant nervous system development nervous system disorder neurofilament neuron development neuron loss neuronal cell body neurotransmission postnatal prevent protein aggregate protein degradation public health relevance research study response restoration small molecule synaptic failure synaptic function therapy development trafficking voltage

项目摘要

DESCRIPTION (provided by applicant): Alterations in the neuromuscular junction (NMJ) have recently been reported in motor neuron diseases such as Spinal muscular atrophy (SMA); however, little is known about the pathways that regulate synaptic activity and development in motor neurons. Although transcriptional mechanisms have been shown to regulate critical steps in the development of the nervous system, recent studies have highlighted the importance of the ubiquitin proteasome system (UPS) in the development and maintenance of synaptic connections. By regulating ubiquitin signaling pathways, such as kinase activation and the trafficking and abundance of cellular proteins, the UPS can control developmental transition points during the maturation of the nervous system. However, it is not known how the cell regulates available ubiquitin pools required for these processes. Given the distance that separates the motor neuron cell body and endplate, specialized mechanisms must ensure the stable expression of ubiquitin necessary for axon path finding, synaptic targeting and motor endplate maturation. Our studies now demonstrate that the proteasomal deubiquitinating enzyme Usp14 is required for the postnatal development of the motor neuron endplate. Homozygous axJ mice, which are deficient for Usp14, display a resting tremor, hind limb rigidity, reduced muscle mass and die by 8 weeks of age. These mice do not have ubiquitinated protein aggregates or accelerated neuronal cell death, but instead show ubiquitin loss that correlates with impaired motor endplate maturation during the first two weeks of postnatal development. Restoration of ubiquitin levels in the axJ mice increases body mass and motor function and prevents postnatal lethality, indicating that ubiquitin loss can be a major contributor to neuromuscular disease. Our recent studies also demonstrate ubiquitin loss in a mouse model of SMA, which displays impaired NMJ maturation and function similar to the axJ mice, validating the importance of identifying the developmental pathways regulated by ubiquitin. Our working hypothesis is that Usp14 functions to maintain ubiquitin levels required for the development and activity of mammalian synapses. The first aim of this proposal will determine the contribution of ubiquitin loss in the axJ mice to the development and activity of the NMJ. In the second aim, we will investigate a newly proposed catalytic-independent function of Usp14 on the proteasome and determine if it is required for development and synaptic transmission at the NMJ. The third aim is designed to determine the role of motor neurons and motor endplates in the disease process in the axJ mice. The final aim will examine the ubiquitin-dependent pathways that control synaptic maturation and function of the NMJ. This proposal will use a combination of genetics and biochemistry to investigate the essential enzymatic functions of Usp14 on the proteasome and determine how changes in the activity of Usp14 alter signaling pathways required for synaptic development and function. PUBLIC HEALTH RELEVANCE: The ubiquitin proteasome system functions to control cellular pathways by regulating protein levels within cells. Since alterations in protein turnover are believed to be central to several chronic neurological diseases, the identification and analysis of components of the ubiquitin proteasome system will provide new insights into the mechanisms of neurological disease and identify potential targets for therapeutic intervention.

描述（由申请人提供）：最近在运动神经元疾病（例如脊柱肌肉萎缩（SMA））中报道了神经肌肉结（NMJ）的改变；但是，对于调节运动神经元突触活动和发育的途径知之甚少。尽管已证明转录机制可以调节神经系统发展的关键步骤，但最近的研究强调了泛素蛋白酶体系统（UPS）在突触连接的开发和维持中的重要性。通过调节泛素信号传导途径，例如激酶激活以及细胞蛋白的运输和丰度，UPS可以控制神经系统成熟期间的发育过渡点。但是，尚不清楚细胞如何调节这些过程所需的泛素池。鉴于将运动神经元细胞体和终板分开的距离，专门的机制必须确保轴突路径查找，突触靶向和运动端板成熟所必需的泛素表达。我们的研究现在表明，运动神经元终板的产后发育需要蛋白酶体去泛素化酶USP14。对于USP14不足的纯合子AXJ小鼠，表现出静止的震颤，后肢刚度，肌肉质量降低，并在8周龄时死亡。这些小鼠没有泛素化的蛋白质聚集体或加速神经元细胞死亡，而是显示出泛素损失，在产后发育的前两周与运动终板成熟受损相关。 AXJ小鼠中泛素水平的恢复会增加体重和运动功能，并防止产后致死性，这表明泛素丧失可能是导致神经肌肉疾病的主要因素。我们最近的研究还表明，在SMA的小鼠模型中，泛素损失显示出与AXJ小鼠相似的NMJ成熟和功能受损，从而验证了识别泛素蛋白调节的发育途径的重要性。我们的工作假设是USP14的功能可维持哺乳动物突触的发展和活动所需的泛素水平。该提案的第一个目的将确定AXJ小鼠中泛素损失对NMJ的发育和活动的贡献。在第二个目标中，我们将研究USP14在蛋白酶体上的新提出的催化无关的功能，并确定是否需要NMJ的开发和突触传播。第三个目的旨在确定运动神经元和运动终板在AXJ小鼠中疾病过程中的作用。最终目标将检查控制NMJ的突触成熟和功能的泛素依赖性途径。该建议将使用遗传学和生物化学的组合来研究USP14在蛋白酶体上的基本酶促功能，并确定USP14活动的变化如何改变突触发育和功能所需的信号传导途径。公共卫生相关性：泛素蛋白酶体系统通过调节细胞内的蛋白质水平来控制细胞途径。由于蛋白质更新的改变被认为是几种慢性神经系统疾病的核心，因此对泛素蛋白酶体系统组成部分的鉴定和分析将为神经疾病机理提供新的见解，并确定治疗干预的潜在目标。