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αB-crystallin is a sensor for assembly intermediates and for the subunit topology of desmin intermediate filaments

Sharma, S.; Conover, G.; Elliott, J.E.; Perng, M.D.; Herrmann, H.; Quinlan, R.A.

αB-crystallin is a sensor for assembly intermediates and for the subunit topology of desmin intermediate filaments Thumbnail


Authors

S. Sharma

G. Conover

J.E. Elliott

M.D. Perng

H. Herrmann



Abstract

Mutations in the small heat shock protein chaperone CRYAB (αB-crystallin/HSPB5) and the intermediate filament protein desmin, phenocopy each other causing cardiomyopathies. Whilst the binding sites for desmin on CRYAB have been determined, desmin epitopes responsible for CRYAB binding and also the parameters that determine CRYAB binding to desmin filaments are unknown. Using a combination of co-sedimentation centrifugation, viscometric assays and electron microscopy of negatively stained filaments to analyse the in vitro assembly of desmin filaments, we show that the binding of CRYAB to desmin is subject to its assembly status, to the subunit organization within filaments formed and to the integrity of the C-terminal tail domain of desmin. Our in vitro studies using a rapid assembly protocol, C-terminally truncated desmin and two disease-causing mutants (I451M and R454W) suggest that CRYAB is a sensor for the surface topology of the desmin filament. Our data also suggest that CRYAB performs an assembly chaperone role because the assembling filaments have different CRYAB-binding properties during the maturation process. We suggest that the capability of CRYAB to distinguish between filaments with different surface topologies due either to mutation (R454W) or assembly protocol is important to understanding the pathomechanism(s) of desmin-CRYAB myopathies.

Citation

Sharma, S., Conover, G., Elliott, J., Perng, M., Herrmann, H., & Quinlan, R. (2017). αB-crystallin is a sensor for assembly intermediates and for the subunit topology of desmin intermediate filaments. Cell Stress and Chaperones, 22(4), 613-626. https://doi.org/10.1007/s12192-017-0788-7

Journal Article Type Article
Acceptance Date Mar 16, 2017
Online Publication Date May 3, 2017
Publication Date May 3, 2017
Deposit Date Mar 22, 2017
Publicly Available Date Mar 22, 2017
Journal Cell Stress and Chaperones
Print ISSN 1355-8145
Electronic ISSN 1466-1268
Publisher Springer
Peer Reviewed Peer Reviewed
Volume 22
Issue 4
Pages 613-626
DOI https://doi.org/10.1007/s12192-017-0788-7

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Publisher Licence URL
http://creativecommons.org/licenses/by/4.0/

Copyright Statement
Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the
Creative Commons license, and indicate if changes were made.







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