Abstract：
TAR DNA-binding protein 43 (TDP-43) is a nucleic acid-binding protein found in the nucleus that accumulates in the cytoplasm under pathological conditions, leading to proteinopathies, such as frontotemporal dementia and ALS. An emerging area of TDP-43 research is represented by the study of its post-translational modifications, the way they are connected to disease-associated mutations, and what this means for pathological processes. Recently, we described a novel mutation in TDP-43 in an early onset ALS case that was affecting a potential phosphorylation site in position 375 (S375G). A preliminary characterization showed that both the S375G mutation and its phosphomimetic variant, S375E, displayed altered nuclear-cytoplasmic distribution and cellular toxicity. To better investigate these effects, here we established cell lines expressing inducible WT, S375G, and S375E TDP-43 variants. Interestingly, we found that these mutants do not seem to affect well-studied aspects of TDP-43, such as RNA splicing or autoregulation, or protein conformation, dynamics, or aggregation, although they do display dysmorphic nuclear shape and cell cycle alterations. In addition, RNA-Seq analysis of these cell lines showed that although the disease-associated S375G mutation and its phosphomimetic S375E variant regulate distinct sets of genes, they have a common target in mitochondrial apoptotic genes. Taken together, our data strongly support the growing evidence that alterations in TDP-43 post-translational modifications can play a potentially important role in disease pathogenesis and provide a further link between TDP-43 pathology and mitochondrial health.
摘要：
TARDNA结合蛋白43（TDP-43）是一种在细胞核中发现的核酸结合蛋白，在病理条件下在细胞质中积累，导致蛋白质病，如额颞叶痴呆和ALS。TDP-43研究的一个新兴领域是其翻译后修饰的研究。它们与疾病相关突变的联系方式，以及这对病理过程意味着什么。最近,我们描述了在一个早发性ALS病例中TDP-43的新突变,该突变影响了375位的一个潜在磷酸化位点(S375G).初步鉴定表明，S375G突变及其磷模拟变异体，S375E,显示改变的核-细胞质分布和细胞毒性。为了更好地研究这些影响，在这里，我们建立了表达诱导型WT的细胞系，S375G,和S375ETDP-43变体。有趣的是,我们发现，这些突变体似乎并不影响TDP-43的研究方面，如RNA剪接或自动调节，或蛋白质构象，动力学,或聚合，尽管它们确实显示出异形核形状和细胞周期改变。此外,这些细胞系的RNA-Seq分析表明，尽管疾病相关的S375G突变及其磷模拟S375E变体调节不同的基因集，它们在线粒体凋亡基因中有一个共同的靶标。一起来看,我们的数据有力地支持了越来越多的证据,即TDP-43翻译后修饰的改变在疾病发病机制中可能发挥重要作用,并在TDP-43病理和线粒体健康之间提供了进一步的联系.
