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 (eIF5AHypK50) 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 eIF5AHypK50 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 eIF5AHypK50. These findings are the first to provide a novel pathway and potential therapeutic targets that require further investigation in models of TDP-43 proteinopathies.
Digital Object Identifier (DOI)
This work was supported by the College of Pharmacy Start-up Funds and COP New Investigator Seed Grant, University of South Florida FL, USA.
Smeltzer, Shayna; Quadri, Zainuddin; Miller, Abraian; Zamudio, Frank; Hunter, Jordan; Stewart, Nicholas J.F.; Saji, Sheba; Lee, Daniel C.; Chaput, Dale; and Selenica, Maj-Linda B., "Hypusination of Eif5a Regulates Cytoplasmic TDP-43 Aggregation and Accumulation in a Stress-Induced Cellular Model" (2020). Sanders-Brown Center on Aging Faculty Publications. 171.
Supplementary Table 1. Top 50 proteins identified in co-IP with eIF5AHypK50 by MS.
1-s2.0-S0925443920302878-mmc2.docx (15 kB)
Supplementary Table 2. Top twenty molecular functions were assigned using EBI Gene Ontology Database (GOA).
1-s2.0-S0925443920302878-mmc3.docx (15 kB)
Supplementary Table 3. Top twenty biological processes were assigned using EBI Gene Ontology Database (GOA).
1-s2.0-S0925443920302878-mmc4.xlsx (14 kB)
Supplementary Table 4. List of antibodies and drugs used in this study, corresponding catalog numbers, dilutions, companies, and protein targets or function.