Defining the Role of Poly ADP-ribose in Biomolecular Condensation in ALS and FTLD

项目总结 聚腺苷二磷酸核糖(PAR)是一种类似RNA的蛋白质修饰，其失调与年龄有关。 依赖性神经退行性疾病包括肌萎缩侧索硬化症、帕金森氏症和阿尔茨海默病。 PAR是应激颗粒的核心成分，是一种无膜核糖核蛋白(Rnp)。 可导致异常蛋白质聚集导致神经病理的颗粒。与RNA不同，PAR 可以形成线形和分枝结构。引人注目的是，PAR聚合酶的抑制剂， 是FDA批准的一类抗癌药物，在细胞模型中被证明可以减轻神经毒性 神经退行性变，反映PAR在神经毒性中的潜在作用。约翰斯的两个实验室 由Sua Myong(生物物理系)和Anthony K.L.Leung领导的霍普金斯大学 (生物化学和分子生物学系)汇集了 分子成像、化学和蛋白质组学方法研究PAR-1的分子基础 导致神经退行性变的蛋白质凝聚和聚集机制 疾病，这可能为开发治疗方法铺平新的道路。我们最近发现的一种标准杆 FUS液-液相的改性方法(Leung等，Mol Cell，2019)及其机理 ALS/FTLD相关病例的分离(Myong等人，Mol Cell，2019)将我们置于理想位置 解决了PAR在生物分子缩合中所起的鲜为人知的作用 神经退行性疾病。在初步研究中，我们发现(I)PAR是非常 一种位于应激颗粒中的RNA结合蛋白，能有效凝聚FUS(在肉瘤中融合) 与ALS/FTLD有关；(Ii)PAR靶向蛋白质组富含应激颗粒 组件。在这些令人兴奋的结果的基础上，我们建议揭示标准杆在驾驶中的作用 利用单分子、生化、中尺度、生物物理进行生物分子缩合 和蜂窝平台。

PROJECT SUMMARY Poly ADP-ribose (PAR) is an RNA-like protein modification whose dysregulation is linked to age- dependent neurodegenerative diseases including ALS, Parkinson’s and Alzheimer’s disease. PAR is a core component of stress granules, a type of membraneless ribonucleoprotein (RNP) granules that can seed aberrant protein aggregation leading to neuropathology. Unlike RNA, PAR can form into both linear and branched structures. Strikingly, inhibitors of PAR polymerase, which is a class of FDA-approved anticancer drugs, were shown to mitigate neurotoxicity in cell models of neurodegeneration, reflecting a potential role of PAR in neurotoxicity. Two laboratories at Johns Hopkins University led by Sua Myong (Biophysics department) and Anthony K. L. Leung (Department of Biochemistry and Molecular Biology ) bring together orthogonal expertise in molecular imaging, chemical and proteomic methods to investigate the molecular basis of PAR- driven protein condensation and aggregation mechanism responsible for neurodegenerative diseases, which may pave new ways of developing therapy. Our recent discovery of a PAR modifying method (Leung et al, Mol Cell, 2019) and mechanism of FUS liquid-liquid phase separation in ALS/FTLD-linked cases (Myong et al, Mol Cell, 2019) places us in an ideal position for tackling the poorly understood role of PAR in biomolecular condensation implicated in neurodegenerative diseases. In Preliminary Studies, we discovered that (i) PAR is extremely potent in condensing FUS (fused in sarcoma), an RNA binding protein localized in stress granules and implicated in ALS/FTLD and (ii) PAR targeted proteome is enriched in stress granule components. Building on these exciting results, we propose to uncover the role of PAR in driving biomolecular condensation by employing single molecule, biochemical, meso-scale, biophysical and cellular platforms.