Michalska, Karolina; Zhang, Kaiming; March, Zachary; Hatzos - Skintges, Catherine; Pintile, Grigore; Bigelow, Lance; Castellano, Laura; Miles, Leann; Jackrel, Meredith; Chuang, Edward; Jedrzejczak, Robert; Shorter, James; Chiu, Wah; Joachimiak, Andrzej
Hsp104 is an AAA+ protein disaggregase with powerful amyloid-remodeling activity. All nonmetazoan eukaryotes express Hsp104while eubacteria express an Hsp104 ortholog, ClpB. However, most studies have focused on Hsp104 from Saccharomyces cerevisiae and ClpB orthologs from two eubacterial species. Thus, the natural spectrum of Hsp104/ClpB molecular architectures and protein-remodeling activities remains largely unexplored. Here, we report two structures of Hsp104 from the thermophilic fungus Calcarisporiella thermophila (CtHsp104), a 2.70 ångström crystal structure and 4.0 ångström cryo-electron microscopy structure. Both structures reveal left-handed, helical assemblies with all domains clearly resolved. We thus provide the highest resolution and most complete view of Hsp104 hexamers to date. We also establish that CtHsp104 antagonizes several toxic protein-misfolding events in vivo where S. cerevisiae Hsp104 is ineffective, including rescue of TDP-43, polyglutamine, and alpha-synuclein toxicity. Wesuggest that natural Hsp104 variation is an invaluable, untapped resource for illuminating therapeutic disaggregases for fatal neurodegenerative diseases.