The functional roles of the unstructured N- and C-terminal regions in aB-crystallin and other mammalian small heat-shock proteins
Date
2017
Authors
Carver, John
Grosas, Aidan
Ecroyd, Heath
Quinlan, Roy A.
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Volume Title
Publisher
Cell Stress Society International
Abstract
Small heat-shock proteins (sHsps), such as αB-crystallin, are one of the major classes of molecular chaperone proteins. In vivo, under conditions of cellular stress, sHsps are the principal defence proteins that prevent large-scale protein aggregation. Progress in determining the structure of sHsps has been significant recently, particularly in relation to the conserved, central and β-sheet structured α-crystallin domain (ACD). However, an understanding of the structure and functional roles of the N- and C-terminal flanking regions has proved elusive mainly because of their unstructured and dynamic nature. In this paper, we propose functional roles for both flanking regions, based around three properties: (i) they act in a localised crowding manner to regulate interactions with target proteins during chaperone action, (ii) they protect the ACD from deleterious amyloid fibril formation and (iii) the flexibility of these regions, particularly at the extreme C-terminus in mammalian sHsps, provides solubility for sHsps under chaperone and non-chaperone conditions. In the eye lens, these properties are highly relevant as the crystallin proteins, in particular the two sHsps αA- and αB-crystallin, are present at very high concentrations
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Keywords
AlphaB-crystallin, Small heat-shock proteins, Molecular chaperone, Structure, Function, Unstructured regions
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Source
Cell Stress and Chaperones
Type
Journal article
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2099-12-31
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