p66Shc mediated effects on ROS signaling and cytoskeletal remodeling

哺乳动物细胞使用一种叫做线粒体的特殊细胞器来分解营养物质，并产生高水平的三磷酸腺苷（一种能量的化学形式）。为了产生ATP，线粒体在消耗氧气的同时产生二氧化碳和水。氧自由基是线粒体代谢过程中产生的潜在有害副产物。在衰老过程中，哺乳动物经常表现出氧自由基的产生增加，或者解毒能力下降，尤其是在被称为神经元的特殊脑细胞中。随着年龄增长，线粒体自由基产生增加的机制尚不清楚。有趣的是，小鼠p66Shc基因的缺失导致对氧化暴露的耐受性增加和寿命延长。最近的研究表明，p66Shc蛋白可以在暴露于某些形式的压力后从细胞质（细胞的主要液体）转移到线粒体中。一旦进入线粒体，p66Shc就会引发氧自由基形成增加，从而促进一系列变化，包括细胞形状、运动的改变，在某些情况下还会导致细胞死亡。这些观察结果表明，p66Shc是氧自由基产生、氧化敏感性、细胞形态和机体衰老的主要调节因子。然而，p66Shc控制这些过程的确切机制尚不清楚。利用我实验室开发的各种新技术，我们将探索p66Shc诱导培养的神经细胞系产生氧自由基导致控制细胞形态，运动和信号传导过程的特定蛋白质氧化的假设。我们认为，随着年龄的增长，这些蛋白质的氧化会导致蛋白质活性的改变和神经元功能的受损。本研究结果将为研究神经元衰老过程的分子机制提供新的见解。

Mammalian cells used specialized organelles called mitochondria to break down nutrients and generate high levels of ATP, a chemical form of energy. In order to generate ATP, mitochondria consume oxygen while at the same time producing carbon dioxide and water. Oxygen radicals are potentially harmful by-products that arise during mitochondrial metabolism. During the aging process, mammals frequently exhibit increased production of oxygen radicals, or the decreased ability to detoxify them, particularly in specialized brain cells called neurons. The mechanism responsible for increased mitochondrial radical production that occurs with age is poorly understood. Interestingly, loss of the p66Shc gene in mice results in increased tolerance to oxidant exposure and extended lifespan. Recent studies have shown that the p66Shc protein can move from the cytosol, the main fluid containing portion of a cell, into mitochondria following exposure to certain forms of stress. Once in the mitochondria, p66Shc triggers increased oxygen radical formation thereby promoting a series of changes including alterations in cell shape, movement and, in certain circumstances, cell death. These observations indicate that p66Shc is a major regulator of oxygen radical production, oxidant sensitivity, cell morphology and organismal aging. However the precise mechanism by which p66Shc controls these processes is poorly understood. Using a variety of novel techniques developed in my lab we will explore the hypothesis that p66Shc induced oxygen radical production in cultured neuronal cell lines leads to oxidation of specific proteins which control cell morphology, movement and signaling processes. We believe that oxidation of these proteins lead to altered protein activity and compromised neuronal function with age. The results of the proposed study will provide novel insight into the molecular mechanisms controlling the aging process in neurons.