Liquid-Liquid Phase Separation Enhances TDP-43 LCD Aggregation but Delays Seeded Aggregation

Donya Pakravan, Emiel Michiels, Anna Bratek-Skicki, Mathias De Decker, Joris Van Lindt, David Alsteens, Sylvie Derclaye, Philip Van Damme, Joost Schymkowitz, Frederic Rousseau, Peter Tompa, Ludo Van Den Bosch

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

Aggregates of TAR DNA-binding protein (TDP-43) are a hallmark of several neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS). Although TDP-43 aggregates are an undisputed pathological species at the end stage of these diseases, the molecular changes underlying the initiation of aggregation are not fully understood. The aim of this study was to investigate how phase separation affects self-aggregation and aggregation seeded by pre-formed aggregates of either the low-complexity domain (LCD) or its short aggregation-promoting regions (APRs). By systematically varying the physicochemical conditions, we observed that liquid-liquid phase separation (LLPS) promotes spontaneous aggregation. However, we noticed less efficient seeded aggregation in phase separating conditions. By analyzing a broad range of conditions using the Hofmeister series of buffers, we confirmed that stabilizing hydrophobic interactions prevail over destabilizing electrostatic forces. RNA affected the cooperativity between LLPS and aggregation in a "reentrant" fashion, having the strongest positive effect at intermediate concentrations. Altogether, we conclude that conditions which favor LLPS enhance the subsequent aggregation of the TDP-43 LCD with complex dependence, but also negatively affect seeding kinetics.

Original languageEnglish
Article number548
Number of pages21
JournalBiomolecules
Volume11
Issue number4
DOIs
Publication statusPublished - 8 Apr 2021

Bibliographical note

Funding Information:
Funding: This research was supported by VIB, the KU Leuven (C1 and “Opening the Future” Fund), the “Fund for Scientific Research Flanders” (FWO-Vlaanderen) and the ALS Liga België (A Cure for ALS). D.P. is doctoral fellow of the VIB international PhD program. PVD holds a senior clinical investigatorship of FWO-Vlaanderen and is supported by the E. von Behring Chair for Neuromuscular and Neurodegenerative Disorders and the KU Leuven funds “Een Hart voor ALS”, “Laeversfonds voor ALS Onderzoek” and the “Valéry Perrier Race against ALS Fund”.

Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.

Keywords

  • Amyotrophic Lateral Sclerosis/metabolism
  • DNA-Binding Proteins/chemistry
  • Fluorescence Recovery After Photobleaching
  • Humans
  • Hydrophobic and Hydrophilic Interactions
  • Liquid-Liquid Extraction
  • Peptides/chemical synthesis
  • Protein Aggregates
  • Protein Domains
  • RNA/chemistry
  • Recombinant Proteins/biosynthesis
  • Static Electricity

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