Elucidating the impact of FIC-1/FICD-mediated AMPylation on polyglutamine aggregation dynamics and toxicity

项目摘要 亨廷顿病（HD）和脊髓小脑共济失调3型（SCA 3）是遗传性衰老相关疾病 相对于其普遍存在， 人口这些病症属于由以下引起的多聚谷氨酰胺（polyQ）扩增疾病家族： 导致不同基因中三核苷酸（CAGn）重复的病理性扩增的突变。增加 CAG重复长度引起含有异常扩展的polyQ片段的蛋白质，其干扰正常的 蛋白质功能和促进错误折叠。这些疾病的毒性被认为部分来自于 病理性包涵体由异常一致的突变蛋白组成，这是在 许多与衰老相关的神经退行性疾病。尽管人们做了大量的努力来破译 然而，在polyQ疾病的潜在毒性方面，在确定polyQ疾病的靶点方面几乎没有取得进展。 治疗干预 近年来，HSP 70的翻译后修饰（PTM）--腺苷酸化（AMPylation）已成为一种新的调控因子 家族分子伴侣，细胞蛋白质质量控制机制的重要组成部分， 错误折叠应力蛋白质的腺苷酸化是由人的fic型腺苷酸化酶FICD及其直系同源物完成的。 FIC-1，在C中。elegans，分别。我们实验室的工作已经确定，FIC-1介导的AMP化直接改变了 polyQ聚集动力学和毒性。此外，我在本提案中提出的初步数据表明， fic-1缺陷足以挽救C.表达聚集倾向polyQs的线虫 以polyQ长度依赖性方式发育。综上所述，这些发现表明，FIC的损失- 1/FICCD介导的AMP化增强了蛋白质稳态网络的能力，以减轻polyQ蛋白诱导的毒性 聚合来 该项目将利用跨学科方法对FICD/FIC-1进行全面表征， 在polyQ疾病中介导的AMP化。为此，我将利用C的强大遗传学。elegans发现 在面对致病性polyQ聚集时促进存活的新途径（Aim 1）。我会一前一后 在源自HD和SCA 3患者干细胞的神经元中采用功能测定，以分析FICD活性如何影响神经元的功能。 在这些疾病模型中影响polyQ聚集和毒性（目的2）。这些研究的结果将推动 我们对AMP化如何调节polyQ疾病中蛋白质稳态的了解。我研究的最终目标是 利用这些发现来开发针对衰老相关疾病的可转化的治疗方法。

PROJECT SUMMARY Huntington’s disease (HD) and spinocerebellar ataxia type 3 (SCA3) are inherited aging-associated diseases that have a devastating impact on patients and family caretakers relative to their prevalence in the general population. These conditions belong to a family of polyglutamine (polyQ) expansion diseases caused by mutations resulting in the pathological expansion of trinucleotide (CAGn) repeats in distinct genes. Increases in CAG repeat length give rise to proteins containing aberrantly expanded polyQ tracts, which interfere with normal protein function and promote misfolding. Toxicity in these diseases is thought to arise in part from the formation of pathological inclusion bodies comprised of aberrantly conformed mutant proteins, a hallmark observed in numerous aging-associated neurodegenerative diseases. Despite extensive efforts to decipher the mechanisms underlying toxicity in polyQ diseases, however, little progress has been made towards identifying targets for therapeutic intervention. Recently, the post-translational modification (PTM), AMPylation, has emerged as a novel regulator of HSP70 family chaperones, crucial components of the cell’s protein quality control machinery that buffer against protein misfolding stress. Protein AMPylation is carried out by the fic-type AMPylase, FICD in humans, and its ortholog FIC-1, in C. elegans, respectively. Work in our lab has established that FIC-1-mediated AMPylation directly alters polyQ aggregation dynamics and toxicity. Further, my preliminary data as presented in this proposal identifies fic-1 deficiency as sufficient to rescue survival of C. elegans expressing aggregation-prone polyQs during development in a polyQ length-dependent manner. Taken together, these findings suggest that the loss of FIC- 1/FICD-mediated AMPylation bolsters proteostasis network capacity to alleviate toxicity induced by polyQ protein aggregation. This project will utilize cross-disciplinary approaches to generate a holistic characterization of FICD/FIC-1- mediated AMPylation in polyQ diseases. To this end, I will harness the powerful genetics of C. elegans to uncover novel pathway(s) that promote survival in the face of pathogenic polyQ aggregation (Aim 1). In tandem, I will employ functional assays in neurons derived from HD and SCA3 patient stem cells to profile how FICD activity affects polyQ aggregation and toxicity in these disease models (Aim 2). The results of these studies will advance our knowledge of how AMPylation regulates proteostasis in polyQ diseases. The ultimate goal of my research is to capitalize on these findings to develop translatable therapeutic approaches for aging-associated diseases.