Abstract
TAR DNA-binding protein 43 (TDP-43) is an RNA-binding protein and a major component of protein aggregates found in amyotrophic lateral sclerosis and several other neurodegenerative diseases. TDP-43 exists as a full-length protein and as two shorter forms of 25 and 35 kDa. Full-length mutant TDP-43s found in amyotrophic lateral sclerosis patients re-localize from the nucleus to the cytoplasm and in part to mitochondria, where they exert a toxic role associated with neurodegeneration. However, induction of mitochondrial damage by TDP-43 fragments is yet to be clarified. In this work, we show that the mitochondrial 35 kDa truncated form of TDP-43 is restricted to the intermembrane space, while the full-length forms also localize in the mitochondrial matrix in cultured neuronal NSC-34 cells. Interestingly, the full-length forms clearly affect mitochondrial metabolism and morphology, possibly via their ability to inhibit the expression of Complex I subunits encoded by the mitochondrial-transcribed mRNAs, while the 35 kDa form does not. In the light of the known differential contribution of the full-length and short isoforms to generate toxic aggregates, we propose that the presence of full-length TDP-43s in the matrix is a primary cause of mitochondrial damage. This in turn may cause oxidative stress inducing toxic oligomers formation, in which short TDP-43 forms play a major role. (Figure presented.).
Original language | English |
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Pages (from-to) | 585-597 |
Number of pages | 13 |
Journal | Journal of Neurochemistry |
Volume | 146 |
Issue number | 5 |
DOIs | |
Publication status | Published - Sep 1 2018 |
Keywords
- amyotrophic lateral sclerosis
- Complex I
- localization
- mitochondria
- neurodegeneration
- TDP-43
ASJC Scopus subject areas
- Biochemistry
- Cellular and Molecular Neuroscience