Synechocystis HSP17 is an amphitropic protein that stabilizes heat-stressed membranes and binds denatured proteins for subsequent chaperone-mediated refolding.

Détails

ID Serval
serval:BIB_9F86B1470964
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Synechocystis HSP17 is an amphitropic protein that stabilizes heat-stressed membranes and binds denatured proteins for subsequent chaperone-mediated refolding.
Périodique
Proceedings of the National Academy of Sciences of the United States of America
Auteur(s)
Török Z., Goloubinoff P., Horváth I., Tsvetkova N.M., Glatz A., Balogh G., Varvasovszki V., Los D.A., Vierling E., Crowe J.H., Vigh L.
ISSN
0027-8424 (Print)
ISSN-L
0027-8424
Statut éditorial
Publié
Date de publication
2001
Volume
98
Numéro
6
Pages
3098-3103
Langue
anglais
Résumé
The small heat shock proteins (sHSPs) are ubiquitous stress proteins proposed to act as molecular chaperones to prevent irreversible protein denaturation. We characterized the chaperone activity of Synechocystis HSP17 and found that it has not only protein-protective activity, but also a previously unrecognized ability to stabilize lipid membranes. Like other sHSPs, recombinant Synechocystis HSP17 formed stable complexes with denatured malate dehydrogenase and served as a reservoir for the unfolded substrate, transferring it to the DnaK/DnaJ/GrpE and GroEL/ES chaperone network for subsequent refolding. Large unilamellar vesicles made of synthetic and cyanobacterial lipids were found to modulate this refolding process. Investigation of HSP17-lipid interactions revealed a preference for the liquid crystalline phase and resulted in an elevated physical order in model lipid membranes. Direct evidence for the participation of HSP17 in the control of thylakoid membrane physical state in vivo was gained by examining an hsp17(-) deletion mutant compared with the isogenic wild-type hsp17(+) revertant Synechocystis cells. We suggest that, together with GroEL, HSP17 behaves as an amphitropic protein and plays a dual role. Depending on its membrane or cytosolic location, it may function as a "membrane stabilizing factor" as well as a member of a multichaperone protein-folding network. Membrane association of sHSPs could antagonize the heat-induced hyperfluidization of specific membrane domains and thereby serve to preserve structural and functional integrity of biomembranes.
Mots-clé
Cell Membrane, Cyanobacteria/genetics, Cyanobacteria/metabolism, Heat-Shock Proteins/genetics, Heat-Shock Proteins/metabolism, Heating, Lipid Bilayers/metabolism, Lipid Metabolism, Liposomes/metabolism, Malate Dehydrogenase/metabolism, Membrane Fluidity, Molecular Chaperones/genetics, Molecular Chaperones/metabolism, Protein Denaturation, Protein Folding, Thylakoids/metabolism
Pubmed
Web of science
Open Access
Oui
Création de la notice
24/01/2008 21:02
Dernière modification de la notice
20/08/2019 16:05
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