The major inducible small heat shock protein HSP20-3 in the tardigrade Ramazzottius varieornatus forms filament-like structures and is an active chaperone.

Al-Ansari, Mohammad; Fitzsimons, Taylor; Wei, Wenbin; Goldberg, Martin W; Kunieda, Takekazu; Quinlan, Roy A

Abstract

The tardigrade Ramazzottius varieornatus has remarkable resilience to a range of environmental stresses. In this study, we have characterised two members of the small heat shock protein (sHSP) family in R. varieornatus, HSP20-3 and HSP20-6. These are the most highly upregulated sHSPs in response to a 24 h heat shock at 35 C of adult tardigrades with HSP20-3 being one of the most highly upregulated gene in the whole transcriptome. Both R. varieornatus sHSPs and the human sHSP, CRYAB (HSPB5), were produced recombinantly for comparative structure-function studies. HSP20-3 exhibited a superior chaperone activity than human CRYAB in a heat-induced protein aggregation assay. Both tardigrade sHSPs also formed larger oligomers than CRYAB as assessed by size exclusion chromatography and transmission electron microscopy of negatively stained samples. Whilst both HSP20-3 and HSP20-6 formed particles that were variable in size and larger than the particles formed by CRYAB, only HSP20-3 formed filament-like structures. The particles and filament-like structures formed by HSP20-3 appear inter-related as the filament-like structures often had particles located at their ends. Sequence analyses identified two unique features; an insertion in the middle region of the N-terminal domain (NTD) and preceding the critical-sequence identified in CRYAB, as well as a repeated QNTN-motif located in the C-terminal domain of HSP20-3. The NTD insertion is expected to affect protein-protein interactions and subunit oligomerisation. Removal of the repeated QNTN-motif abolished HSP20-3 chaperone activity and also affected the assembly of the filament-like structures. We discuss the potential contribution of HSP20-3 to protein condensate formation. [Abstract copyright: Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.]

Citation

Al-Ansari, M., Fitzsimons, T., Wei, W., Goldberg, M. W., Kunieda, T., & Quinlan, R. A. (2024). The major inducible small heat shock protein HSP20-3 in the tardigrade Ramazzottius varieornatus forms filament-like structures and is an active chaperone. Cell Stress and Chaperones, 29(1), 51-65. https://doi.org/10.1016/j.cstres.2023.12.001

• Journal Article Type: Article
• Acceptance Date: Dec 3, 2023
• Online Publication Date: Dec 5, 2023
• Publication Date: 2024-02
• Deposit Date: Mar 26, 2024
• Publicly Available Date: Mar 26, 2024
• Journal: Cell Stress and Chaperones
• Print ISSN: 1355-8145
• Electronic ISSN: 1466-1268
• Publisher: Springer
• Peer Reviewed: Peer Reviewed
• Volume: 29
• Issue: 1
• Pages: 51-65
• DOI: https://doi.org/10.1016/j.cstres.2023.12.001
• Keywords: Tardigrade, chaperone oligomerisation, Protein condensation, Filament-like, Chaperone, Cryptobiosis, Small heat shock protein
• Public URL: https://durham-repository.worktribe.com/output/2275944