Coordination of PAR and Ub signaling in mitochondria

项目概要/摘要 在过去的10年里，我们的研究计划旨在发现控制 代谢适应响应营养供应，细胞分化和氧化应激，通过 基因组重编程在NIGMS的支持下，我们为确定 基因转录和翻译的协调调节机制， 线粒体应激反应（MSR）。我们的工作已经确定了非降解性泛素化的关键作用， 这两个过程，表明GPS 2-K63泛素化的内源性抑制剂- 线粒体和细胞核之间的相互作用是维持线粒体稳态的重要策略。作为 作为对这些机制研究的补充，我们还在NIDDK和 国防部-的生理相关性和翻译潜力GPS 2介导的调节， 乳腺癌和肥胖相关疾病中的泛素信号传导。总之，这些研究揭示了 GPS 2介导的K63 Ub信号限制在促进代谢适应和 线粒体在应激和细胞分化过程中重塑。这一庞大的工作机构突出了我们的 我们在该领域的专业知识和我们的独特地位，以进一步调查之间的串扰，这一新确定的 途径和其他参与调节线粒体功能的PTM。特别是，我们将把我们的未来 泛素化和ADP-核糖基化之间的串扰研究。这些PTM在 调节核基因组稳定性、先天免疫和应激诱导的翻译调节。然而，在这方面， 它们在调节线粒体功能中的关系尚未被研究。事实上，尽管存在 几十年来，线粒体中ADP核糖基化活性是已知的， 酶/s一直难以捉摸，阻碍了对线粒体蛋白质的作用和调节进行更详细的研究 通过ADP核糖基化。我们最近发现NEURL 4是一个专门的ADP核糖基， 转移酶在应激诱导和GPS 2介导的重编程的调节下，我们现在正处于 进行这些研究的立场。我们提出了一个跨越两个主要领域的研究计划：1）调查 响应线粒体应激的线粒体逆行信号传导的空间和功能调节，以及2） 探索泛素化和ADP-核糖基化在调节线粒体稳态中的相互作用。 我们的研究计划解决三个关键问题：i）线粒体逆行信号的空间调控; ii）线粒体逆行信号传导对ADP-核糖基化调节的功能贡献，和 跨亚细胞区室的泛素化; iii）协调的泛素化的分子机制 ADP-核糖基化/泛素化的调节。成功完成拟议的研究将导致更好的 理解通过翻译后修饰调节线粒体稳态的机制 并可能揭示用于治疗目的的靶向调节策略。

Project Summary/Abstract Over the past 10 years, our research program has aimed at discovering molecular mechanisms that control metabolic adaptation in response to nutrient availability, cellular differentiation, and oxidative stress through genomic reprogramming. With NIGMS support, we have made significant contributions to identifying mechanisms responsible for the coordinated regulation of gene transcription and translation during the Mitochondrial Stress Response (MSR). Our work has identified a key role for non-degradative ubiquitination in both processes, showing that the regulated shuttling of GPS2 – an endogenous inhibitor of K63 ubiquitination – between mitochondria and nucleus is an essential strategy for maintaining mitochondrial homeostasis. As a complement to these mechanistic studies, we also investigated – in projects supported by NIDDK and the Department of Defense – the physiological relevance and translational potential GPS2-mediated regulation of ubiquitin signaling in breast cancer and obesity-associated disorders. Together, these studies have revealed the importance of GPS2-mediated restriction of K63Ub signaling in promoting metabolic adaptation and mitochondria remodeling during stress and cellular differentiation. This large body of work highlights our expertise in the field and our unique position to further investigate the crosstalk between this newly identified pathway and other PTMs involved in regulating mitochondrial function. In particular, we will focus our future studies on the crosstalk between ubiquitination and ADP-ribosylation. These PTMs work in tandem in the regulation of nuclear genome stability, innate immunity and stress-induced translational regulation. However, their relationship in regulating mitochondrial function has not yet been investigated. In fact, although the presence of ADP-ribosylation activity in mitochondria was known for decades, the identity of the mitochondrial ART enzyme/s has been elusive, hindering more detailed studies on the role and regulation of mitochondrial proteins through ADP-ribosylation. As we recently identified NEURL4 as a mitochondria-dedicated ADP-ribosyl transferase under the regulation of stress-induced and GPS2-mediated reprogramming, we are now in the position of carrying those studies. We propose a research plan spanning two major areas:1) Investigating the spatial and functional regulation of mitochondria retrograde signaling in response to mitochondrial stress and 2) Exploring the crosstalk between ubiquitination and ADP-ribosylation in regulating mitochondrial homeostasis. Our research plan addresses three key problems: i) the spatial regulation of mitochondria retrograde signaling; ii) the functional contribution of mitochondria retrograde signaling to the regulation of ADP-ribosylation and ubiquitination across subcellular compartments; iii) the molecular mechanisms underlying the coordinated regulation of ADP-ribosylation/ ubiquitination. Successful completion of the proposed studies will lead to a better understanding of the mechanisms regulating mitochondria homeostasis through post-translational modifications and possibly reveal regulatory strategies to be targeted for therapeutic purposes.