Brain mitochondria and glycogen synthase kinase-3beta

摘要 NADH：泛醌氧化还原酶（复合物-I）是氧化磷酸化相关疾病受损的最常见部位。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。虽然复合物-I缺乏症的临床症状是明确的，但对线粒体中调节复合物-I功能的信号通路了解较少。最近，我们的研究小组发现，不受调节的糖原合成酶激酶-3 β（GSK 3 β）活性抑制复合物-I功能，增加活性氧的产生，片段线粒体，并增加细胞对复合物-I毒素的敏感性。GSK 3 β是一种信号蛋白，已知会影响代谢途径和大脑发育。其调节是多层次的，这意味着其作用可以通过其丝氨酸-9位点的磷酸化、蛋白质-蛋白质相互作用以及其细胞内定位来控制。有趣的是，还没有人完全阐明它在大脑中的细胞内分布。在初步结果中，我们发现，一个显着的部分GSK 3 β存在于脑线粒体。此外，我们现在已经发现了以前未发现的口袋GSK 3 β表达在其他细胞区室。本提案的第一个具体目标是通过电子显微镜充分确定GSK 3 β在小鼠和人脑中的神经解剖学超微结构分布。以前没有进行过这种彻底的调查。内源性GSK 3 β信号在线粒体中的作用尚不完全清楚。在具体目标2中，目标是检验内源性GSK 3 β调节复合物-I功能的假设。通过分子和药理学方法操纵内源性线粒体GSK 3 β活性以评估GSK 3 β信号传导对复合物I的影响。蛋白质STAT 3和GRIM 19在线粒体中结合在一起，两者都参与复合物I的功能。还已知GSK 3 β与这两种蛋白质结合。我们的假设是，GSK 3 β信号通过由GSK 3 β、STAT 3和GRIM 19组成的三方蛋白复合物调节复合物-I的活性。通过这个项目，我们希望阐明线粒体GSK 3 β信号及其对复合物I的影响，前景，我们的研究结果可用于发现减轻复合物I疾病的措施。

Abstract 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-3beta (GSK3beta) activity inhibits complex-I function, increases reactive oxygen species production, fragments mitochondria, and increases the cell's sensitivity to complex-I toxins. GSK3beta 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 GSK3beta exists in brain mitochondria. Furthermore, we have now found previously undiscovered pockets of GSK3beta expression in other cellular compartments. The first specific aim of this proposal is to fully determine the neuroanatomic ultrastructural distribution of GSK3beta in the mouse and human brain by electron microscopy. A thorough investigation of this sort has not been conducted previously. The actions of endogenous GSK3beta signaling in the mitochondria are not fully known. In specific aim 2, the goal is to test the hypothesis that endogenous GSK3beta modulates complex-I functions. Endogenous mitochondrial GSK3beta activity is manipulated by molecular and pharmacological methods to assess the affects of GSK3beta 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 GSK3beta associates with both these proteins. Our hypothesis is that GSK3beta signaling regulates complex-I activity through a tripartite protein composite consisting of GSK3beta, STAT3, and GRIM19. With this project we hope to elucidate mitochondrial GSK3beta signaling and its affects on complex-I with the prospect that our findings could be used to discover measures to alleviate complex-I disorders.