Redox-mediated regulation of an evolutionarily conserved cross-β structure formed by the TDP43 low complexity domain.

Lin, Yi; Zhou, Xiaoming; Kato, Masato; Liu, Daifei; Ghaemmaghami, Sina; Tu, Benjamin P; McKnight, Steven L · Proc Natl Acad Sci U S A · 2020

basic_science · Level V

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Abstract

A methionine-rich low complexity (LC) domain is found within a C-terminal region of the TDP43 RNA-binding protein. Self-association of this domain leads to the formation of labile cross-β polymers and liquid-like droplets. Treatment with H<sub>2</sub>O<sub>2</sub> caused phenomena of methionine oxidation and droplet melting that were reversed upon exposure of the oxidized protein to methionine sulfoxide reductase enzymes. Morphological features of the cross-β polymers were revealed by H<sub>2</sub>O<sub>2</sub>-mediated footprinting. Equivalent TDP43 LC domain footprints were observed in polymerized hydrogels, liquid-like droplets, and living cells. The ability of H<sub>2</sub>O<sub>2</sub> to impede cross-β polymerization was abrogated by the prominent M337V amyotrophic lateral sclerosis-causing mutation. These observations may offer insight into the biological role of TDP43 in facilitating synapse-localized translation as well as aberrant aggregation of the protein in neurodegenerative diseases.

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