1. Full-length TDP-43 and its C-terminal domain form filaments in vitro having non-amyloid properties
- Author
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Claudio Canale, Lisa D. Cabrita, Fabrizio Chiti, Mirella Vivoli Vega, Martino Calamai, Amanda Penco, John Christodoulou, Annalisa Relini, Giulia Fani, and Claudia Capitini
- Subjects
Circular dichroism ,Amyloid ,TDP-43 filaments ,030204 cardiovascular system & hematology ,Protein aggregation ,protein aggregation ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Motor neuron disease ,protein misfolding ,TDP-43 fibrils ,mental disorders ,Internal Medicine ,medicine ,Protein secondary structure ,Motor neuron diseaseTDP-43 fibrilsTDP-43 filamentsprotein misfoldingprotein aggregation ,nutritional and metabolic diseases ,Frontotemporal lobar degeneration ,medicine.disease ,nervous system diseases ,Congo red ,chemistry ,Biophysics ,Thioflavin ,Protein folding ,030217 neurology & neurosurgery - Abstract
Accumulation of ubiquitin-positive, tau- and alpha-synuclein-negative intracellular inclusions of TDP-43 in the central nervous system represents the major hallmark correlated to amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U). Such inclusions have variably been described as amorphous aggregates or more structured deposits having amyloid properties. Here we have purified full-length TDP-43 (FL TDP-43) and its C-terminal domain (Ct TDP-43) to investigate the morphological, structural and tinctorial features of aggregates formedin vitroby them at pH 7.4 and 37 degrees C. AFM images indicate that both protein variants show a tendency to form filaments. Moreover, we show that both FL TDP-43 and Ct TDP-43 filaments possess a largely disordered secondary structure, as ascertained by far-UV circular dichroism and Fourier transform infra-red spectroscopy, do not bind Congo red and induce a very weak increase of thioflavin T fluorescence, indicating the absence of a clear amyloid-like signature.
- Published
- 2020