Structural and functional characterization of ATP synthase c-subunit leak channel and its role in AD pathogenesis

摘要 线粒体和突触功能障碍是早期的病理特征，也是神经系统疾病的驱动力。 阿尔茨海默病（AD）病理学。A β在AD患者脑内异常聚集 个体和AD小鼠模型中，导致线粒体Ca2+超载和 线粒体通透性转换孔（mPTP）。mPTP的延长开放触发外部 线粒体膜破裂、细胞色素c释放和下游细胞活化 死亡之路在过去的一年里，mPTP一直是广泛科学研究的中心。 几十年来，它仍然是当今生物学中最神秘的现象之一 由于其分子组成存在争议，且缺乏其孔隙结构信息。 我们最近已经证明了ATP合酶C亚基环在形成ATP酶中的新作用。 mPTP通道尽管如此，ATP合酶c亚基泄漏的门控机制， 尚未发现启动其开放的通道和构象变化。 在这个建议中，我们将使用单粒子低温电子显微镜（cryo-EM）来识别高- 解析结构和ATP合成酶泄漏通道的开放构象的存在下， 信道调制器我们还将进行ATP合酶的原位结构分析， A β暴露的原代海马神经元和线粒体内的功能环境 通过使用冷冻电子断层扫描（cryo-ET）从AD的小鼠模型中分离。在这个项目中 我们还将研究ATP合成酶泄漏通道作为一种新的细胞死亡途径的直接作用 在AD发病机制中，我们将测试该通道的药理学抑制是否会拯救 A β诱导的细胞死亡。成功完成这项提案将揭示 线粒体通透性转换的分子机制，ATP的原子结构 合成酶泄漏通道，并将有助于开发新的治疗AD，靶向ATP 合成酶

Abstract Mitochondrial and synaptic dysfunction are early pathological features and a driving force of Alzheimer's disease (AD) pathology. Aβ is found to accumulate abnormally in the brains of AD individuals and in an AD mouse models leading to mitochondrial Ca2+ overload and activation of mitochondrial permeability transition pore (mPTP). Prolonged opening of mPTP triggers outer mitochondrial membrane rupture, release of cytochrome c and activation of downstream cell death pathways. The mPTP has been at the center of extensive scientific research for the last several decades but it still remains as one of the most mysterious phenomena in biology today due to its controversial molecular composition and the lack of structural information of its pore. We have recently demonstrated the novel role of ATP synthase c-subunit ring in forming the channel of mPTP. Nevertheless, the gating mechanism of the ATP synthase c-subunit leak channel and conformational changes initiating its opening are yet to be discovered. In this proposal, we will use single-particle cryo-electron microscopy (cryo-EM) to identify the high- resolution structure and the open conformation of ATP synthase leak channel in the presence of channel modulators. We will also perform in situ structural analysis of ATP synthase in its functional environment within the Aβ-exposed primary hippocampal neurons and in mitochondria isolated from the mouse models of AD by using cryo-electron tomography (cryo-ET). In this project we will also investigate the direct role of ATP synthase leak channel as a novel cell death pathway in AD pathogenesis; we will test whether the pharmacological inhibition of this channel will rescue neurons from Aβ-induced cell death. Successful completion of this proposal will reveal the molecular mechanism(s) of mitochondrial permeability transition, the atomic structure of ATP synthase leak channel, and will aid in the development of new treatments for AD, targeting ATP synthase.