TDP-43 Alpha-Helical Structure Tunes Liquid-Liquid Phase Separation and Function
Abstract
Liquid-liquid phase separation (LLPS) is involved in the formation of membraneless organelles (MLOs) associated with RNA processing. The RNA-binding protein TDP-43 is present in several MLOs, undergoes LLPS, and has been linked to the pathogenesis of amyotrophic lateral sclerosis (ALS). While some ALS-associated mutations in TDP-43 disrupt self-interaction and function, here we show that designed single mutations can enhance TDP-43 assembly and function via modulating helical structure. Using molecular simulation and NMR spectroscopy, we observe large structural changes upon dimerization of TDP-43. Two conserved glycine residues (G335 and G338) are potent inhibitors of helical extension and helix-helix interaction, which are removed in part by variants at these positions, including the ALS-associated G335D. Substitution to helix-enhancing alanine at either of these positions dramatically enhances phase separation in vitro and decreases fluidity of phase-separated TDP-43 reporter compartments in cells. Furthermore, G335A increases TDP-43 splicing function in a minigene assay. Therefore, the TDP-43 helical region serves as a short but uniquely tunable module where application of biophysical principles can precisely control assembly and function in cellular and synthetic biology applications of LLPS.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 04, 2020
- Accession Number
- AD1095581
Entities
People
- Alexander E Conicella
- Alexandra M D'ordine
- Gregory L. Dignon
- Gul H Zerze
- Hermann B Schmidt
- Jeetain Mittal
- Nicolas L. Fawzi
- Rajat Rohatgi
- Young C. Kim
- Yuna M Ayala
Organizations
- United States Naval Research Laboratory