Therapeutic genetic variation revealed in diverse Hsp104 homologs.

Zachary M March,Ophir Shalem,Robert P Jedrzejczak,Karolina Michalska,Edward Gomes,Guy A Caldwell,Kim A Caldwell,Edward Chuang,Laura M Castellano,Katelyn Sweeney,Corey W Willicott,Jiabei Lin,Xiaohui Yan,Andrzej Joachimiak,Meredith E Jackrel,James Shorter,Hanna Kim

doi:10.7554/elife.57457

Abstract

The AAA+ protein disaggregase, Hsp104, increases fitness under stress by reversing stress-induced protein aggregation. Natural Hsp104 variants might exist with enhanced, selective activity against neurodegenerative disease substrates. However, natural Hsp104 variation remains largely unexplored. Here, we screened a cross-kingdom collection of Hsp104 homologs in yeast proteotoxicity models. Prokaryotic ClpG reduced TDP-43, FUS, and α-synuclein toxicity, whereas prokaryotic ClpB and hyperactive variants were ineffective. We uncovered therapeutic genetic variation among eukaryotic Hsp104 homologs that specifically antagonized TDP-43 condensation and toxicity in yeast and TDP-43 aggregation in human cells. We also uncovered distinct eukaryotic Hsp104 homologs that selectively antagonized α-synuclein condensation and toxicity in yeast and dopaminergic neurodegeneration in C. elegans. Surprisingly, this therapeutic variation did not manifest as enhanced disaggregase activity, but rather as increased passive inhibition of aggregation of specific substrates. By exploring natural tuning of this passive Hsp104 activity, we elucidated enhanced, substrate-specific agents that counter proteotoxicity underlying neurodegeneration.

Highlights

143 cytoplasmic aggregation and toxicity. These yeast models have proven to be a 144 powerful platform that have enabled the discovery of several important genetic
693 Figure 8-figure supplement 1J, K for accompanying Western blots). These results suggest that additional residues or contacts in the NBD2:CTD unit are necessary but not sufficient for TtHsp104 and TlHsp104 to suppress Syn
776 proteins implicated in human neurodegenerative diseases

Summary

Introduction

Alternative protein folding and aberrant phase transitions underpin fatal50 neurodegenerative diseases (Chuang et al, 2018; Mathieu et al, 2020).51 Diseases such as Parkinson’s disease (PD) and amyotrophic lateral sclerosis52 (ALS) have distinct clinical manifestations but are united by the prominent53 pathological accumulation of misfolded protein conformers (Peng et al, 2020).54 The proteins implicated in each disease can adopt a range of misfolded55 conformations (Peng et al, 2020; Shorter, 2017). Alternative protein folding and aberrant phase transitions underpin fatal. 50 neurodegenerative diseases (Chuang et al, 2018; Mathieu et al, 2020). 52 (ALS) have distinct clinical manifestations but are united by the prominent. 53 pathological accumulation of misfolded protein conformers (Peng et al, 2020). 54 The proteins implicated in each disease can adopt a range of misfolded. 55 conformations (Peng et al, 2020; Shorter, 2017). 56 (αSyn) accumulates in toxic soluble oligomers and amyloid fibers that are a major.

Methods

Results

Conclusion