A biosensor of protein foldedness identifies increased "holdase" activity of chaperones in the nucleus following increased cytosolic protein aggregation.

Autor:	Raeburn CB; Department of Biochemistry and Pharmacology, and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, VIC, Australia., Ormsby AR; Department of Biochemistry and Pharmacology, and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, VIC, Australia., Cox D; Department of Biochemistry and Pharmacology, and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, VIC, Australia., Gerak CA; Department of Biochemistry and Pharmacology, and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, VIC, Australia., Makhoul C; Department of Biochemistry and Pharmacology, and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, VIC, Australia., Moily NS; Department of Biochemistry and Pharmacology, and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, VIC, Australia., Ebbinghaus S; Physical and Theoretical Chemistry, TU Braunschweig, 38106 Germany and Braunschweig Integrated Centre of Systems Biology, Braunschweig, Germany., Dickson A; Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan, USA., McColl G; Melbourne Dementia Research Centre, Florey Institute of Neuroscience and Mental Health and University of Melbourne, Parkville, VIC, Australia., Hatters DM; Department of Biochemistry and Pharmacology, and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, VIC, Australia. Electronic address: dhatters@unimelb.edu.
Jazyk:	angličtina
Zdroj:	The Journal of biological chemistry [J Biol Chem] 2022 Aug; Vol. 298 (8), pp. 102158. Date of Electronic Publication: 2022 Jun 17.
DOI:	10.1016/j.jbc.2022.102158
Abstrakt:	Chaperones and other quality control machinery guard proteins from inappropriate aggregation, which is a hallmark of neurodegenerative diseases. However, how the systems that regulate the "foldedness" of the proteome remain buffered under stress conditions and in different cellular compartments remains incompletely understood. In this study, we applied a FRET-based strategy to explore how well quality control machinery protects against the misfolding and aggregation of "bait" biosensor proteins, made from the prokaryotic ribonuclease barnase, in the nucleus and cytosol of human embryonic kidney 293T cells. We found that those barnase biosensors were prone to misfolding, were less engaged by quality control machinery, and more prone to inappropriate aggregation in the nucleus as compared with the cytosol, and that these effects could be regulated by chaperone Hsp70-related machinery. Furthermore, aggregation of mutant huntingtin exon 1 protein (Httex1) in the cytosol appeared to outcompete and thus prevented the engagement of quality control machinery with the biosensor in the cytosol. This effect correlated with reduced levels of DNAJB1 and HSPA1A chaperones in the cell outside those sequestered to the aggregates, particularly in the nucleus. Unexpectedly, we found Httex1 aggregation also increased the apparent engagement of the barnase biosensor with quality control machinery in the nucleus suggesting an independent implementation of "holdase" activity of chaperones other than DNAJB1 and HSPA1A. Collectively, these results suggest that proteostasis stress can trigger a rebalancing of chaperone abundance in different subcellular compartments through a dynamic network involving different chaperone-client interactions. Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article. (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)
Databáze:	MEDLINE
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