Single Acetylation-mimetic Mutation in TDP-43 Nuclear Localization Signal Disrupts Importin α1/β Signaling

• Published in: Journal of molecular biology Vol. 436; no. 20; p. 168751
• Main Authors: Ko, Ying-Hui, Lokareddy, Ravi K., Doll, Steven G., Yeggoni, Daniel P., Girdhar, Amandeep, Mawn, Ian, Klim, Joseph R., Rizvi, Noreen F., Meyers, Rachel, Gillilan, Richard E., Guo, Lin, Cingolani, Gino
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 15.10.2024
• Subjects: Acetylation; Active Transport, Cell Nucleus; alpha Karyopherins - genetics; alpha Karyopherins - metabolism; ALS; Amyotrophic Lateral Sclerosis - genetics; Amyotrophic Lateral Sclerosis - metabolism; Amyotrophic Lateral Sclerosis - pathology; beta Karyopherins - genetics; beta Karyopherins - metabolism; Cell Nucleus - metabolism; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Humans; importin α1; importin β; Mutation; nuclear localization signal; Nuclear Localization Signals - genetics; Nuclear Localization Signals - metabolism; Protein Binding; Protein Processing, Post-Translational; Signal Transduction; TDP-43; RRMs; CC; YFP; SPA; ALS; PTM; IBB; importin β; nuclear localization signal; CFP; Imp; importin α1; SAXS; SEC; SDS-PAGE; CTD; NLS; TDP-43; FTD; M.W; FRET; cryo-EM; NTD
• ISSN: 0022-2836; 1089-8638; 1089-8638
• DOI: 10.1016/j.jmb.2024.168751

[Display omitted] •Single acetylation mimetic mutation in the NLS mislocalizes TDP-43 in SH-SY5Y neuroblastoma cells.•Single acetylation mimetic mutation in the NLS disrupts binding to importin α1/β in vitro.•Both importin α1/β and free importin β exert anti-aggregation activity toward TDP-43 in vitro.•Importin α1/β bound to TDP-43 adopts an elongated structure. Cytoplasmic aggregation of the TAR-DNA binding protein of 43 kDa (TDP-43) is the hallmark of sporadic amyotrophic lateral sclerosis (ALS). Most ALS patients with TDP-43 aggregates in neurons and glia do not have mutations in the TDP-43 gene but contain aberrantly post-translationally modified TDP-43. Here, we found that a single acetylation-mimetic mutation (K82Q) near the TDP-43 minor Nuclear Localization Signal (NLS) box, which mimics a post-translational modification identified in an ALS patient, can lead to TDP-43 mislocalization to the cytoplasm and irreversible aggregation. We demonstrate that the acetylation mimetic disrupts binding to importins, halting nuclear import and preventing importin α1/β anti-aggregation activity. We propose that perturbations near the NLS are an additional mechanism by which a cellular insult other than a genetically inherited mutation leads to TDP-43 aggregation and loss of function. Our findings are relevant to deciphering the molecular etiology of sporadic ALS.