PROPITIOUS · Liquid liquid phase separation mediated protein fibrillation leading to neurodegenerative diseases

Neurodegenerative disorders are the leading cause of physical and cognitive disability, currently affecting ~15% population worldwide with estimated global cost of healthcare accosiated with them expected to at least double in the next 20 years. Five most common neurodegenerative diseases, including ALS and FTD, are linked to formation of protein deposits in patient tissues and are currently without treatment options that would prevent or alter the disease progression. ALS and FTD pathology is characterised by accumulation and formation of insoluble protein deposits formed by proteins, like TDP-43, FUS and DAXX. These proteins undergo liquid-liquid phase transition (LLPS) in cells forming non-membrane bound organelles, which are important in RNA processing and stress responses of cells but their dysregulation acts a precursor to protein fibrillation. In this project we will, therefore, combine traditional biophysical approaches with modern molecular dynamics simulations and solution state nuclear magnetic resonance to discern this complex behaviour leading to LLPS, and gain molecular insight into its onset. Major outcomes of the project are (1) Develop the necessary simulation tools by reparametrizing currently available force fields using experimental data; (2) Apply the simulation tool and analytical methods to interactions between oligonucleotides and ions with proteins and compare results to experimental data; (3) Map phases and coacervation of DAXX in the presence of nucleotides and ions; (4) identify residues crucial for fibrillation and determine their role in cellular LLPS; (5) Apply high-throughput virtual screening to design proteins aggregation breaking ligands with therapeutic potential Outcomes of this project will importantly enhance our understanding at a mechanistic level, the role of these factors in promoting LLPS in cell biology.