Identification of human proteins that modify misfolding and proteotoxicity of pathogenic Ataxin-1

• Verfasst von: Petrakis, Spyros [VerfasserIn]
• Verfasst von: Boutros, Michael [VerfasserIn]
• Titel: Identification of human proteins that modify misfolding and proteotoxicity of pathogenic Ataxin-1
• Verf.angabe: Spyros Petrakis, Tamás Raskó, Jenny Russ, Ralf P. Friedrich, Martin Stroedicke, Sean-Patrick Riechers, Katja Muehlenberg, Angeli Möller, Anita Reinhardt, Arunachalam Vinayagam, Martin H. Schaefer, Michael Boutros, Hervé Tricoire, Miguel A. Andrade-Navarro, Erich E. Wanker
• E-Jahr: 2012
• Jahr: August 16, 2012
• Umfang: 19 S.
• Fussnoten: Gesehen am 06.06.2018
• Titel Quelle: Enthalten in: Public Library of SciencePLoS Genetics
• Ort Quelle: San Francisco, Calif. : Public Library of Science, 2005
• Jahr Quelle: 2012
• Band/Heft Quelle: 8(2012,8) Artikel-Nummer e1002897, 19 Seiten
• ISSN Quelle: 1553-7404
• DOI: doi:10.1371/journal.pgen.1002897
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: Cell fusion
• Sach-SW: Luciferase
• Sach-SW: Plasmid construction
• Sach-SW: Predictive toxicology
• Sach-SW: Protein domains
• Sach-SW: Protein extraction
• Sach-SW: Small interfering RNAs
• Sach-SW: Toxicity
• K10plus-PPN: 157611967X

Abstract

Proteins with long, pathogenic polyglutamine (polyQ) sequences have an enhanced propensity to spontaneously misfold and self-assemble into insoluble protein aggregates. Here, we have identified 21 human proteins that influence polyQ-induced ataxin-1 misfolding and proteotoxicity in cell model systems. By analyzing the protein sequences of these modifiers, we discovered a recurrent presence of coiled-coil (CC) domains in ataxin-1 toxicity enhancers, while such domains were not present in suppressors. This suggests that CC domains contribute to the aggregation- and toxicity-promoting effects of modifiers in mammalian cells. We found that the ataxin-1-interacting protein MED15, computationally predicted to possess an N-terminal CC domain, enhances spontaneous ataxin-1 aggregation in cell-based assays, while no such effect was observed with the truncated protein MED15ΔCC, lacking such a domain. Studies with recombinant proteins confirmed these results and demonstrated that the N-terminal CC domain of MED15 (MED15CC) per se is sufficient to promote spontaneous ataxin-1 aggregation in vitro. Moreover, we observed that a hybrid Pum1 protein harboring the MED15CC domain promotes ataxin-1 aggregation in cell model systems. In strong contrast, wild-type Pum1 lacking a CC domain did not stimulate ataxin-1 polymerization. These results suggest that proteins with CC domains are potent enhancers of polyQ-mediated protein misfolding and aggregation in vitro and in vivo.