SWS/NTE function in neurodegeneration and axonopathy

SWS/NTE 在神经退行性变和轴突病中的作用

• 批准号: 8076167
• 负责人: Doris Kretzschmar
• 金额: $ 33.01万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2014-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8076167
• 关键词: Address; Affect; Axonal Neuropathy; Binding; Binding Proteins; Binding Sites; Biological Models; Catalytic Domain; Cessation of life; Cheese; Collaborations; Complement 3a; Complex; Cyclic AMP-Dependent Protein Kinases; Cyclic Nucleotides; Diagnosis; Dimerization; Disease; Dissociation; Drosophila genus; Embryo; Endoplasmic Reticulum; Exhibits; Funding; Gene Mutation; Genes; Hereditary Spastic Paraplegia; Homeostasis; Human; Immunoprecipitation; Inherited; Intoxication; Lead; Letters; Maintenance; Membrane; Membrane Lipids; Modeling; Molecular; Motor Neurons; Mus; Mutate; Mutation; Nerve Degeneration; Nervous system structure; Neurons; Neuropathy; Organophosphates; Orthologous Gene; Pathway interactions; Pattern; Pesticides; Phenotype; Phosphorylation; Phosphorylation Site; Phosphotransferases; Play; Process; Proteins; Regulation; Role; Sarin; Spastic Paraplegia; Subway; System; Testing; Tokyo; Toxic effect; Toxin; Transgenic Organisms; Vertebrates; Yeasts; axonal degeneration; axonopathy; base; dimer; esterase; fly; human disease; in vivo; insight; mouse model; mutant; nerve agent; neuron loss; neuronal survival; neuropathy target esterase; neurotoxicity; novel; progressive neurodegeneration; relating to nervous system; research study; response; tool; yeast two hybrid system

DESCRIPTION (provided by applicant): The focus of this proposal is to study the basic mechanisms underlying axonopathy and progressive neurodegeneration that are caused by mutations in the swiss cheese (sws) gene. SWS is the ortholog of human Neuropathy Target Esterase (NTE), a key player in organophosphate (OP)-induced delayed neuropathy (OPIDN) which is caused by organophosphates found in many pesticides and nerve agents. Neuronal loss of NTE in mice results in a pattern of progressive degeneration of the nervous system that is surprisingly similar to mutant flies, while the complete loss of NTE is embryonic lethal. In addition, recently described mutations in the human gene cause a hereditary spastic paraplegia called NTE--related Motor Neuron Disorder. The functional conservation between SWS and NTE was confirmed by experiments showing that mouse NTE can replace the fly protein, reverting the degenerative phenotype caused by the loss of SWS. SWS and NTE can both hydrolyze the same artificial substrate, and both have been connected with membrane lipid homeostasis; however, their endogenous functions are still largely unknown. During the previous funding period, several domains in the SWS protein were identified and shown to be functionally required. This includes a domain that binds a specific catalytic subunit of protein kinase A (PKA-C3), thereby inhibiting its kinase activity. PKA-C3, and its vertebrate orthologs PrKX in human and Pkare in mice, form a novel class of catalytic subunits that are more closely related to each other than to other catalytic subunits within the same species. They are all expressed in the nervous system, but their functions are so far unknown. The current proposal will tests the hypothesis that SWS and PKA-C3 form an unconventional PKA complex that has a dual function: regulating the intracellular localization and kinase activity of PKA-C3, and controlling the esterase activity of SWS. Furthermore, the role of this unique PKA subunit in neural survival, sws-induced phenotypes, and organophosphate induced toxicity will be investigated. Due to the high conservation of these proteins between Drosophila and vertebrates, the proposed studies in this well-established model system can provide important insights into the mechanisms that lead to progressive degeneration in the related human disease and in toxin-induced neuropathy. Beyond the scope of the immediate proposal, these studies may also expand our understanding of common mechanisms of axonopathy and neuronal cell death, which also occurs in response to a variety of other neuronal insults.

描述（由申请人提供）：该提案的重点是研究由瑞士奶酪（sws）基因突变引起的轴突病和进行性神经变性的基本机制。 SWS 是人类神经病变靶酯酶 (NTE) 的直系同源物，NTE 是有机磷酸盐 (OP) 诱导的迟发性神经病变 (OPIDN) 的关键参与者，这种迟发性神经病变是由许多杀虫剂和神经毒剂中发现的有机磷酸盐引起的。小鼠 NTE 神经元缺失会导致神经系统进行性退化，与突变果蝇惊人地相似，而 NTE 完全缺失则导致胚胎死亡。此外，最近描述的人类基因突变会导致遗传性痉挛性截瘫，称为 NTE 相关运动神经元疾病。实验证实了SWS和NTE之间的功能保守性，表明小鼠NTE可以替代果蝇蛋白，恢复因SWS缺失而引起的退化表型。 SWS和NTE都可以水解相同的人工底物，并且都与膜脂稳态有关；然而，它们的内源功能仍然很大程度上未知。在之前的资助期间，SWS 蛋白中的几个结构域被鉴定出来并被证明是功能所需的。其中包括一个结合蛋白激酶 A (PKA-C3) 特定催化亚基的结构域，从而抑制其激酶活性。 PKA-C3 及其在人类中的脊椎动物直系同源物 PrKX 和在小鼠中的 Pkare，形成了一类新型催化亚基，它们之间的关系比同一物种内的其他催化亚基之间的关系更密切。它们都在神经系统中表达，但其功能至今未知。目前的提案将测试SWS和PKA-C3形成非常规PKA复合物的假设，该复合物具有双重功能：调节PKA-C3的细胞内定位和激酶活性，并控制SWS的酯酶活性。此外，还将研究这种独特的 PKA 亚基在神经存活、sws 诱导的表型和有机磷诱导的毒性中的作用。由于这些蛋白质在果蝇和脊椎动物之间高度保守，在这个完善的模型系统中进行的研究可以为导致相关人类疾病和毒素诱导的神经病变进行性退化的机制提供重要的见解。除了当前提议的范围之外，这些研究还可能扩大我们对轴突病和神经元细胞死亡的常见机制的理解，轴突病和神经元细胞死亡也发生在对各种其他神经元损伤的反应中。