TAR DNA-binding protein 43 (TDP-43) is a nuclear RNA/DNA binding protein involved in mRNA metabolism. Aberrant mislocalization to the cytoplasm and formation of phosphorylated/aggregated TDP-43 inclusions remains the hallmark pathology in a spectrum of neurodegenerative diseases, including frontotemporal disorders and Alzheimer's disease. Eukaryotic Translation Initiation Factor 5A undergoes a unique post-translation modification of lysine to hypusine (K50), which determines eIF5A binding partners. We used a sodium arsenite-induced cellular stress model to investigate the role of hypusinated eIF5A (eIF5A^HypK50) in governing TDP-43 cytoplasmic mislocalization and accumulation in stress granule. Our proteomics and functional data provide evidence that eIF5A interacts with TDP-43 in a hypusine-dependent manner. Additionally, we showed that following stress TDP-43 interactions with eIF5A^HypK50 were induced both in the cytoplasm and stress granules. Pharmacological reduction of hypusination or mutations of lysine residues within the hypusine loop decreased phosphorylated and insoluble TDP-43 levels. The proteomic and biochemical analysis also identified nuclear pore complex importins KPNA1/2, KPNB1, and RanGTP as interacting partners of eIF5A^HypK50. These findings are the first to provide a novel pathway and potential therapeutic targets that require further investigation in models of TDP-43 proteinopathies.

TAR DNA 结合蛋白 43 (TDP-43) 是一种参与 mRNA 代谢的核 RNA/DNA 结合蛋白。细胞质的异常错误定位和磷酸化/聚集的 TDP-43 包涵体的形成仍然是一系列神经退行性疾病（包括额颞叶疾病和阿尔茨海默病）的标志性病理学。真核翻译起始因子 5A 经历赖氨酸独特的翻译后修饰，将赖氨酸修饰为马尿嘧啶 (K50)，从而决定 eIF5A 结合伴侣。我们使用亚砷酸钠诱导的细胞应激模型来研究 hypuslated eIF5A (eIF5A ^HypK50 ) 在控制 TDP-43 细胞质错误定位和应激颗粒中积累中的作用。我们的蛋白质组学和功能数据提供了 eIF5A 以依赖于马尿苷的方式与 TDP-43 相互作用的证据。此外，我们还发现，应激后 TDP-43 与 eIF5A ^HypK50的相互作用在细胞质和应激颗粒中均被诱导。 hypusination 的药理学减少或 hypusine 环内赖氨酸残基的突变降低了磷酸化和不溶性 TDP-43 水平。蛋白质组学和生化分析还鉴定出核孔复合体输入蛋白 KPNA1/2、KPNB1 和 RanGTP 作为 eIF5A ^HypK50的相互作用伙伴。这些发现首次提供了新的途径和潜在的治疗靶点，需要在 TDP-43 蛋白病模型中进行进一步研究。