J Proteome Res. 2018 Apr 6;17(4):1712-1729. doi: 10.1021/acs.jproteome.8b00126. Epub 2018 Mar 22.
The TAR DNA-binding protein of 43 kDa (TDP-43) is a dual function RNA- and DNA-binding protein with varied cellular functions. In degenerating motor neurons in amyotrophic lateral sclerosis (ALS), TDP-43 relocalizes from the nucleus to the cytosol, where it is sequestered into inclusions. It is likely that the pathogenic role of TDP-43 in ALS can involve either a gain or a loss of function, depending on the nature of its RNA or protein interactor. However, while TDP-43 binding partners have been identified in a range of model systems and from the human brain, interactors from human spinal-cord tissue have not. In this study, we have characterized both protein and RNA TDP-43 interactors from neuropathologically normal (control) and ALS-affected ventral lumbar spinal cord, including sporadic ALS (sALS) and familial cases harboring either a A4T mutant SOD1 or a 3' UTR *c.41G>A mutant FUS/TLS or expressing pathological c9orf72 expanded repeats. RNA interactors with TDP-43 were similar between the control and ALS spinal cords examined regardless of genotype. In contrast, protein interactors with TDP-43 did demonstrate differences, with the sALS and mtSOD1 harboring cases examined differing from the protein interactors identified in the FUS 3' UTR mutation and c9orf72 repeat-positive cases.
TDP-43 是一种具有双重功能的 RNA 和 DNA 结合蛋白，具有多种细胞功能。在肌萎缩侧索硬化症（ALS）中退化的运动神经元中，TDP-43 从细胞核重新分布到细胞质，在细胞质中被隔离成包含体。TDP-43 在 ALS 中的致病作用可能涉及功能的获得或丧失，这取决于其 RNA 或蛋白相互作用物的性质。然而，尽管在一系列模型系统和人脑组织中已经鉴定出 TDP-43 的结合伴侣，但尚未从人脊髓组织中鉴定出相互作用物。在这项研究中，我们对神经病理学正常（对照）和 ALS 受累的腰骶部脊髓中的 TDP-43 的蛋白和 RNA 相互作用物进行了特征描述，包括散发性 ALS（sALS）和携带 A4T 突变 SOD1 或 3'UTR * c.41G > A 突变 FUS/TLS 或表达病理性 c9orf72 扩展重复的家族病例。无论基因型如何，对照和 ALS 脊髓中的 TDP-43 RNA 相互作用物都相似。相比之下，与 TDP-43 具有蛋白相互作用物的 sALS 和 mtSOD1 携带病例与在 FUS 3'UTR 突变和 c9orf72 重复阳性病例中鉴定出的蛋白相互作用物不同。
