Exposure of a cryptic Hsp70 binding site determines the cytotoxicity of the ALS-associated SOD1-mutant A4V

Filip Claes; Stanislav Rudyak; Angela S Laird; Nikolaos Louros; Jacinte Beerten; Maja Debulpaep; Emiel Michiels; Rob van der Kant; Joost Van Durme; Greet De Baets; Bert Houben; Meine Ramakers; Kristy Yuan; Serene S L Gwee; Sara Hernandez; Kerensa Broersen; Mikael Oliveberg; Barbara Moahamed; Janine Kirstein; Wim Robberecht; Frederic Rousseau; Joost Schymkowitz

doi:10.1093/protein/gzaa008

Exposure of a cryptic Hsp70 binding site determines the cytotoxicity of the ALS-associated SOD1-mutant A4V

Protein Eng Des Sel. 2019 Dec 31;32(10):443-457. doi: 10.1093/protein/gzaa008.

Authors

Filip Claes^{1

2}, Stanislav Rudyak^{1

2

3}, Angela S Laird^{4

5}, Nikolaos Louros^{1

2}, Jacinte Beerten^{1

6}, Maja Debulpaep^{1

6}, Emiel Michiels^{1

2}, Rob van der Kant^{1

2}, Joost Van Durme^{1

2

6}, Greet De Baets^{1

2

6}, Bert Houben^{1

2}, Meine Ramakers^{1

2}, Kristy Yuan⁵, Serene S L Gwee⁵, Sara Hernandez⁴, Kerensa Broersen^{1

6}, Mikael Oliveberg⁷, Barbara Moahamed⁸, Janine Kirstein⁸, Wim Robberecht⁴, Frederic Rousseau^{1

2}, Joost Schymkowitz^{1

2}

Affiliations

¹ VIB Center for Brain & Disease Research, Switch Laboratory, Herestraat 49, Leuven, Belgium.
² KU Leuven, Department of Cellular and Molecular Medicine, Switch Laboratory, Herestraat 49, Leuven, Belgium.
³ Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Leninskiy Prospekt, 14, Moscow 119991, Russia.
⁴ VIB, Center for Brain and Disease Research, Laboratory of Neurobiology, Herestraat 49, Leuven, Belgium.
⁵ Center for Motor Neuron Disease Research, Department of Biomedical Science, Faculty of Medicine, Macquarie University, Balaclava Rd, Macquarie Park, Sydney NSW 2109, Australia.
⁶ Applied Stem Cell Technologies, University of Twente, Technical Medical Centre, Drienerlolaan 5, Enschede, The Netherlands.
⁷ Stockholm University, Department of Biochemistry and Biophysics, Frescativägen, 114 19 Stockholm, Sweden.
⁸ Universität Bremen, Fachbereich 2 Biologie/ Chemie, Postfach 330 440, Bremen, Germany.

PMID: 32399571
DOI: 10.1093/protein/gzaa008

Abstract

The accumulation of toxic protein aggregates is thought to play a key role in a range of degenerative pathologies, but it remains unclear why aggregation of polypeptides into non-native assemblies is toxic and why cellular clearance pathways offer ineffective protection. We here study the A4V mutant of SOD1, which forms toxic aggregates in motor neurons of patients with familial amyotrophic lateral sclerosis (ALS). A comparison of the location of aggregation prone regions (APRs) and Hsp70 binding sites in the denatured state of SOD1 reveals that ALS-associated mutations promote exposure of the APRs more than the strongest Hsc/Hsp70 binding site that we could detect. Mutations designed to increase the exposure of this Hsp70 interaction site in the denatured state promote aggregation but also display an increased interaction with Hsp70 chaperones. Depending on the cell type, in vitro this resulted in cellular inclusion body formation or increased clearance, accompanied with a suppression of cytotoxicity. The latter was also observed in a zebrafish model in vivo. Our results suggest that the uncontrolled accumulation of toxic SOD1A4V aggregates results from insufficient detection by the cellular surveillance network.

Keywords: ALS; HSP70; SOD1; cytotoxicity.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amyotrophic Lateral Sclerosis / genetics*
Binding Sites
HSP70 Heat-Shock Proteins / metabolism*
Humans
Models, Molecular
Mutation*
Protein Binding
Protein Conformation
Protein Engineering*
Superoxide Dismutase-1 / chemistry
Superoxide Dismutase-1 / genetics*
Superoxide Dismutase-1 / metabolism*

Substances

HSP70 Heat-Shock Proteins
Superoxide Dismutase-1