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Laurents, D.

Publications and source records attributed to Laurents, D..

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Deciphering the Amyloid Foldome of TDP-43

TDP-43 is an essential regulator of RNA splicing and metabolism and its aggregates play key roles in devastating diseases, including Amyotrophic Lateral Sclerosis (ALS)1, Frontotemporal Dementia (FTD) and Limbic-Predominant Age-Related TDP-43 Encephalopathy (LATE)2. Besides this pathological aggregation, TDP-43s oligomerization also serves vital functions3, which adds urgency to determine pathological conformations of TDP-43. The recently published cryo-EM study by Cao, Eisenberg and coworkers now reveals amyloid structures of putative pathological aggregates from TDP-43s C-terminal region4. Whereas the Cao et al.s cryo-EM structures contain both the hydrophobic and Q/N-rich segments, the data were interpreted mainly through the lens of hydrophobic contacts. However, the Q/N-rich region can form amyloid on its own5,6 and therefore additional considerations of the Q/N-rich segments contributions will advance our understanding of TDP-43 aggregation.

biophysics

Conformational Priming of RepA-WH1 for Functional Amyloid Conversion Detected by NMR Spectroscopy

How proteins with a stable globular fold acquire the amyloid state is still largely unknown. RepA is a versatile plasmidic DNA binding protein, functional either as a transcriptional repressor or as an initiator or inhibitor of DNA replication, the latter through the assembly of an amyloidogenic oligomer. Its N-terminal domain (WH1) is responsible for discrimination between these functional abilities by undergoing hitherto unknown structural changes. Furthermore, when expressed alone, RepA-WH1 behaves as a synthetic prion-like protein causing an amyloid proteinopathy in bacteria. RepA-WH1 is a stable dimer whose conformational dynamics had not been explored. Here we have studied it through NMR {1H}-15N relaxation and H/D exchange kinetics measurements. The N- and the C- terminal -helices, which lock the WH1 fold in each subunit of the dimer, as well as an internal amyloidogenic loop, show reduced stability and are partially unfolded in solution. S4-indigo, a small molecule ligand known to interfere with the amyloid assembly of RepA-WH1, binds to and tethers the N-terminal -helix and a {beta}-hairpin that is involved in dimerization, thus providing evidence for a priming role of fraying ends and dimerization switches in the amyloidogenesis of folded proteins.

biochemistry