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Chang YL, Yang CC, Huang YY, Chen YA, Yang CW, Liao CY, Li H, Wu CS, Lin CH, Teng SC. The HSP40 family chaperone isoform DNAJB6b prevents neuronal cells from tau aggregation. BMC Biol 2023; 21:293. [PMID: 38110916 PMCID: PMC10729500 DOI: 10.1186/s12915-023-01798-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 12/05/2023] [Indexed: 12/20/2023] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is the most common neurodegenerative disorder with clinical presentations of progressive cognitive and memory deterioration. The pathologic hallmarks of AD include tau neurofibrillary tangles and amyloid plaque depositions in the hippocampus and associated neocortex. The neuronal aggregated tau observed in AD cells suggests that the protein folding problem is a major cause of AD. J-domain-containing proteins (JDPs) are the largest family of cochaperones, which play a vital role in specifying and directing HSP70 chaperone functions. JDPs bind substrates and deliver them to HSP70. The association of JDP and HSP70 opens the substrate-binding domain of HSP70 to help the loading of the clients. However, in the initial HSP70 cycle, which JDP delivers tau to the HSP70 system in neuronal cells remains unclear. RESULTS We screened the requirement of a diverse panel of JDPs for preventing tau aggregation in the human neuroblastoma cell line SH-SY5Y by a filter retardation method. Interestingly, knockdown of DNAJB6, one of the JDPs, displayed tau aggregation and overexpression of DNAJB6b, one of the isoforms generated from the DNAJB6 gene by alternative splicing, reduced tau aggregation. Further, the tau bimolecular fluorescence complementation assay confirmed the DNAJB6b-dependent tau clearance. The co-immunoprecipitation and the proximity ligation assay demonstrated the protein-protein interaction between tau and the chaperone-cochaperone complex. The J-domain of DNAJB6b was critical for preventing tau aggregation. Moreover, reduced DNAJB6 expression and increased tau aggregation were detected in an age-dependent manner in immunohistochemical analysis of the hippocampus tissues of a mouse model of tau pathology. CONCLUSIONS In summary, downregulation of DNAJB6b increases the insoluble form of tau, while overexpression of DNAJB6b reduces tau aggregation. Moreover, DNAJB6b associates with tau. Therefore, this study reveals that DNAJB6b is a direct sensor for its client tau in the HSP70 folding system in neuronal cells, thus helping to prevent AD.
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Affiliation(s)
- Ya-Lan Chang
- Department of Microbiology, College of Medicine, National Taiwan University, No. 1, Section 1, Jen-Ai Road, Taipei, 10051, Taiwan
| | - Chan-Chih Yang
- Department of Microbiology, College of Medicine, National Taiwan University, No. 1, Section 1, Jen-Ai Road, Taipei, 10051, Taiwan
| | - Yun-Yu Huang
- Department of Microbiology, College of Medicine, National Taiwan University, No. 1, Section 1, Jen-Ai Road, Taipei, 10051, Taiwan
| | - Yi-An Chen
- Department of Microbiology, College of Medicine, National Taiwan University, No. 1, Section 1, Jen-Ai Road, Taipei, 10051, Taiwan
| | - Chia-Wei Yang
- Department of Microbiology, College of Medicine, National Taiwan University, No. 1, Section 1, Jen-Ai Road, Taipei, 10051, Taiwan
| | - Chia-Yu Liao
- Department of Microbiology, College of Medicine, National Taiwan University, No. 1, Section 1, Jen-Ai Road, Taipei, 10051, Taiwan
| | - Hsun Li
- Department of Neurology, National Taiwan University Hospital, No. 7, Chung-Shan South Road, Taipei, 10051, Taiwan
| | - Ching-Shyi Wu
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Chin-Hsien Lin
- Department of Neurology, National Taiwan University Hospital, No. 7, Chung-Shan South Road, Taipei, 10051, Taiwan.
| | - Shu-Chun Teng
- Department of Microbiology, College of Medicine, National Taiwan University, No. 1, Section 1, Jen-Ai Road, Taipei, 10051, Taiwan.
- Center of Precision Medicine, National Taiwan University, Taipei, 10051, Taiwan.
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Wan Q, Mouton SN, Veenhoff LM, Boersma AJ. A FRET-based method for monitoring structural transitions in protein self-organization. Cell Rep Methods 2022; 2:100184. [PMID: 35475219 PMCID: PMC8960284 DOI: 10.1016/j.crmeth.2022.100184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 08/12/2021] [Accepted: 02/24/2022] [Indexed: 11/04/2022]
Abstract
Proteins assemble into a variety of dynamic and functional structures. Their structural transitions are often challenging to distinguish inside cells, particularly with a high spatiotemporal resolution. Here, we present a fluorescence resonance energy transfer (FRET)-based method for continuous and high-throughput monitoring of protein self-assemblies to reveal well-resolved transient intermediate states. Intermolecular FRET with both the donor and acceptor proteins at the same target protein provides high sensitivity while retaining the advantage of straightforward ratiometric imaging. We apply this method to monitor self-assembly of three proteins. We show that the mutant Huntingtin exon1 (mHttex1) first forms less-ordered assemblies, which develop into fibril-like aggregates, and demonstrate that the chaperone protein DNAJB6b increases the critical saturation concentration of mHttex1. We also monitor the structural changes in fused in sarcoma (FUS) condensates. This method adds to the toolbox for protein self-assembly structure and kinetics determination, and implementation with native or non-native proteins can inform studies involving protein condensation or aggregation.
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Affiliation(s)
- Qi Wan
- DWI – Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52056 Aachen, Germany
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
| | - Sara N. Mouton
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Liesbeth M. Veenhoff
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Arnold J. Boersma
- DWI – Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52056 Aachen, Germany
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