Regulation of mitochondrial homeostasis through retrograde signaling

项目摘要/摘要 因为大多数线粒体蛋白是在核基因组中编码的， 线粒体生物发生与线粒体动态平衡的最终维持 依赖于线粒体损伤时核转录的调节 以及细胞新陈代谢或营养物质供应的变化。然而，这些路径 在哺乳动物细胞中，控制线粒体到细胞核的通讯在很大程度上仍然是 未知。在这里，我们建议研究一种假设，即转录 辅因子GPS2作为一种直接介导物调节线粒体动态平衡 哺乳动物细胞线粒体逆行信号传递的目的如下：i) 鉴定GPS2在促进核编码基因转录激活中的作用 线粒体基因；II)剖析GPS2在线粒体之间穿梭的调节 和细胞核，并定义了调控易位的基因程序；iii)阐明 GPS2逆行易位在调节线粒体动态平衡中的作用至 为了实现这些目标，我们将使用生物化学技术的组合，全基因组 ChIPseq/RNAseq实验和开放的蛋白质组学方法 GPS2调控线粒体基因的分子机制 并阐明控制GPS2的调控策略 逆行易位在线粒体应激状态和在 特化细胞系的分化。整体来说，研究已顺利完成。 在本申请中概述的将：1)确定线粒体调节的新参与者 基因表达并阐明其转录活性的分子机制，2) 剖析了哺乳动物细胞线粒体逆行信号的第一条直接途径， 以及3)揭示了一种意想不到的整合压力和代谢的调控策略 通过抑制非蛋白水解性泛素化在细胞内传递信号。

PROJECT SUMMARY / ABSTRACT Because the majority of mitochondrial proteins are encoded in the nuclear genome, mitochondrial biogenesis and maintenance of mitochondrial homeostasis ultimately depend on nuclear transcription being regulated in response to mitochondrial damage and to changes in cell metabolism or nutrients availability. However, the pathways controlling mitochondria-to-nucleus communication in mammalian cells are still largely unknown. Here, we propose to investigate the hypothesis that the transcriptional cofactor GPS2 regulates mitochondrial homeostasis as a direct mediator of mitochondrial retrograde signaling in mammalian cells with the following Aims: i) Characterize the role of GPS2 in promoting transcriptional activation of nuclear-encoded mitochondrial genes; ii) Dissect the regulation of GPS2 shuttling between mitochondria and nucleus and define the gene programs regulated upon translocation; iii) Elucidate the role of GPS2 retrograde translocation in regulating mitochondrial homeostasis. To achieve these goals, we will use a combination of biochemical techniques, genome wide ChIPseq/RNAseq experiments and open-ended proteomic approaches to dissect the molecular mechanism underlying GPS2-mediated regulation of mitochondrial gene expression in the nucleus and elucidate the regulatory strategies that control GPS2 retrograde translocation both in conditions of mitochondrial stress and during the differentiation of specialized cell lineages. Overall, successful completion of the studies outlined in this application will: 1) identify a novel player in the regulation of mitochondrial gene expression and elucidate the molecular mechanism of its transcriptional activity, 2) dissect the first direct pathway of mitochondrial retrograde signaling in mammalian cells, and 3) reveal an unexpected regulatory strategy for integrating stress and metabolic signaling within the cell through inhibition of non-proteolytic ubiquitination.