Brain mitochondria and glycogen synthase kinase-3beta

描述（由申请人提供）：NADH：泛醌氧化还原酶（复合物- 1）是氧化磷酸化相关疾病最常见的损伤位点。这些疾病包括一些神经发育和神经退行性综合征，如Leigh综合征、MELAS和某些形式的帕金森病。虽然复合体- 1缺乏的临床症状是明确的，但在线粒体中调节复合体- 1功能的信号通路尚不清楚。最近，我们的研究小组发现，不受调节的糖原合成酶激酶-3 （GSK3）活性会抑制复合物- 1的功能，增加活性氧的产生，使线粒体片段化，并增加细胞对复合物- 1毒素的敏感性。GSK3是一种已知影响代谢途径和大脑发育的信号蛋白。它的调控是多层次的，这意味着它的作用可以通过丝氨酸-9位点的磷酸化、蛋白质-蛋白质相互作用和细胞内定位来控制。有趣的是，没有人完全阐明它在大脑细胞内的分布。在初步结果中，我们发现GSK3¿的显著部分存在于脑线粒体中。此外，我们现在已经在其他细胞区室中发现了以前未发现的GSK3¿表达口袋。本提案的第一个具体目的是通过电子显微镜全面确定GSK3¿在小鼠和人脑中的神经解剖超微结构分布。这种彻底的调查以前从未进行过。内源性GSK3信号在线粒体中的作用尚不完全清楚。在具体目标2中，目标是测试内源性GSK3¿调节复合物- 1功能的假设。内源性线粒体GSK3¿活性通过分子和药理学方法来评估GSK3¿信号对复合物- 1的影响。STAT3和GRIM19蛋白在线粒体中结合在一起，两者都参与复合物- 1的功能。我们也知道GSK3¿与这两种蛋白都有关联。我们的假设是GSK3信号通过由GSK3、STAT3和GRIM19组成的三方蛋白复合物调节复合物- 1的活性。通过这个项目，我们希望阐明线粒体GSK3信号传导及其对复合物- 1的影响，并希望我们的发现可以用来发现缓解复合物- 1疾病的措施。

DESCRIPTION (provided by applicant): NADH:ubiquinone oxidoreductase (complex-I) is the most common site of impairment of the oxidative phosphorylation-related disorders. These disorders include some neurodevelopmental and neurodegenerative syndromes such as Leigh syndrome, MELAS, and some forms of Parkinson's disease. While the clinical symptoms of complex-I deficiency are defined, signaling pathways regulating complex-I function in the mitochondria are less understood. Recently, our group found that unregulated glycogen synthase kinase-3¿ (GSK3¿) activity inhibits complex-I function, increases reactive oxygen species production, fragments mitochondria, and increases the cell's sensitivity to complex-I toxins. GSK3¿ is a signaling protein that is known to affect metabolic pathways and brain development. Its regulation is multi-tiered meaning that its actions can be controlled by phosphorylation at its serine-9 site, by protein-protein interactions, and by its intracellular localization. Interestingly, no one has fully elucidated its intracellular distribution in the brain. In preliminary results, we have found that a salient fraction of GSK3¿ exists in brain mitochondria. Furthermore, we have now found previously undiscovered pockets of GSK3¿ expression in other cellular compartments. The first specific aim of this proposal is to fully determine the neuroanatomic ultrastructural distribution of GSK3¿ in the mouse and human brain by electron microscopy. A thorough investigation of this sort has not been conducted previously. The actions of endogenous GSK3¿ signaling in the mitochondria are not fully known. In specific aim 2, the goal is to test the hypothesis that endogenous GSK3¿ modulates complex-I functions. Endogenous mitochondrial GSK3¿ activity is manipulated by molecular and pharmacological methods to assess the affects of GSK3¿ signaling on complex-I. The proteins STAT3 and GRIM19 are bound together in the mitochondria and both are involved in complex-I function. It is also known that GSK3¿ associates with both these proteins. Our hypothesis is that GSK3¿ signaling regulates complex-I activity through a tripartite protein composite consisting of GSK3¿, STAT3, and GRIM19. With this project we hope to elucidate mitochondrial GSK3¿ signaling and its affects on complex-I with the prospect that our findings could be used to discover measures to alleviate complex-I disorders. PUBLIC HEALTH RELEVANCE: This project investigates the intracellular localization and functions of mitochondrial GSK3¿, a protein whose unregulated activity has been previously implicated in severe mitochondrial deficiencies. In humans, mitochondrial dysfunctions have major ramifications on neurodevelopment and neurodegenerative diseases in both infants and adults.