PARylation regulates stress granule dynamics, phase separation, and neurotoxicity of disease-related RNA-binding proteins
PARylation regulates stress granule dynamics, phase separation, and neurotoxicity of disease-related RNA-binding proteins
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PARylation 调节应激颗粒动力学、相分离和疾病相关 RNA 结合蛋白的神经毒性。
DOI：
10.1038/s41422-019-0141-z
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发表时间：
2019-03-01
期刊：
影响因子：
44.1
通讯作者：
Fang, Yanshan
中科院分区：
文献类型：
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作者：
Duan, Yongjia;Du, Aiying;Fang, Yanshan
位于核糖核蛋白（RNP）颗粒中的RNA结合蛋白（RBP），如异质性核糖核蛋白A1（hnRNP A1）和TAR DNA结合蛋白43（TDP - 43）发生突变，会促进异常的蛋白质聚集，这是多种神经退行性疾病，如肌萎缩侧索硬化症（ALS）和额颞叶痴呆（FTD）的病理特征。已知蛋白质翻译后修饰（PTM）可调节RNP颗粒。在本研究中，我们探讨了多聚（ADP - 核糖基）化（PARylation）这一参与DNA损伤修复和细胞死亡的重要翻译后修饰在RNP颗粒相关神经退行性变中的作用。我们发现PARylation水平是含有疾病相关RBP（hnRNP A1和TDP - 43）的RNP颗粒组装 - 解聚动态的主要调节因子。我们发现hnRNP A1既能被PARylated，又能与PARylated蛋白或多聚（ADP - 核糖）（PAR）结合。我们进一步揭示hnRNP A1在K298位点的PARylation控制其核质运输，而通过hnRNP A1的PAR结合基序（PBM）进行的PAR结合调节其与应激颗粒的关联。此外，我们发现PAR不仅显著增强hnRNP A1的液 - 液相分离，还促进hnRNP A1和TDP - 43在体外的共相分离以及在体内的相互作用。最后，在ALS的细胞和果蝇模型中，无论是对PARP进行基因抑制还是药物抑制，都能减轻hnRNP A1和TDP - 43介导的神经毒性。总之，我们的研究结果表明PARylation在调节RNP颗粒动态方面具有新颖且关键的作用，并且PARylation和PAR水平的失调可能通过促进蛋白质聚集而导致ALS疾病的发病机制。
Mutations in RNA-binding proteins (RBPs) localized in ribonucleoprotein (RNP) granules, such as hnRNP A1 and TDP-43, promote aberrant protein aggregation, which is a pathological hallmark of various neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Protein posttranslational modifications (PTMs) are known to regulate RNP granules. In this study, we investigate the function of poly(ADP-ribosyl)ation (PARylation), an important PTM involved in DNA damage repair and cell death, in RNP granule-related neurodegeneration. We reveal that PARylation levels are a major regulator of the assembly-disassembly dynamics of RNP granules containing disease-related RBPs, hnRNP A1 and TDP-43. We find that hnRNP A1 can both be PARylated and bind to PARylated proteins or poly(ADP-ribose) (PAR). We further uncover that PARylation of hnRNP A1 at K298 controls its nucleocytoplasmic transport, whereas PAR-binding via the PAR-binding motif (PBM) of hnRNP A1 regulates its association with stress granules. Moreover, we reveal that PAR not only dramatically enhances the liquid-liquid phase separation of hnRNP A1, but also promotes the co-phase separation of hnRNP A1 and TDP-43 in vitro and their interaction in vivo. Finally, both genetic and pharmacological inhibition of PARP mitigates hnRNP A1- and TDP-43-mediated neurotoxicity in cell and Drosophila models of ALS. Together, our findings suggest a novel and crucial role for PARylation in regulating the dynamics of RNP granules, and that dysregulation in PARylation and PAR levels may contribute to ALS disease pathogenesis by promoting protein aggregation.