Frontiers in Molecular Biosciences (Mar 2023)

Structural polymorphism of the low-complexity C-terminal domain of TDP-43 amyloid aggregates revealed by solid-state NMR

  • Jayakrishna Shenoy,
  • Alons Lends,
  • Mélanie Berbon,
  • Muhammed Bilal,
  • Nadia El Mammeri,
  • Mathilde Bertoni,
  • Ahmad Saad,
  • Estelle Morvan,
  • Axelle Grélard,
  • Sophie Lecomte,
  • François-Xavier Theillet,
  • Alexander K. Buell,
  • Brice Kauffmann,
  • Birgit Habenstein,
  • Antoine Loquet

DOI
https://doi.org/10.3389/fmolb.2023.1148302
Journal volume & issue
Vol. 10

Abstract

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Aberrant aggregation of the transactive response DNA-binding protein (TDP-43) is associated with several lethal neurodegenerative diseases, including amyotrophic lateral sclerosis and frontotemporal dementia. Cytoplasmic neuronal inclusions of TDP-43 are enriched in various fragments of the low-complexity C-terminal domain and are associated with different neurotoxicity. Here we dissect the structural basis of TDP-43 polymorphism using magic-angle spinning solid-state NMR spectroscopy in combination with electron microscopy and Fourier-transform infrared spectroscopy. We demonstrate that various low-complexity C-terminal fragments, namely TDP-13 (TDP-43300–414), TDP-11 (TDP-43300–399), and TDP-10 (TDP-43314–414), adopt distinct polymorphic structures in their amyloid fibrillar state. Our work demonstrates that the removal of less than 10% of the low-complexity sequence at N- and C-termini generates amyloid fibrils with comparable macroscopic features but different local structural arrangement. It highlights that the assembly mechanism of TDP-43, in addition to the aggregation of the hydrophobic region, is also driven by complex interactions involving low-complexity aggregation-prone segments that are a potential source of structural polymorphism.

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