Genetic dissection of the roles of chaperones and proteases in protein folding and degradation in the Escherichia coli cytosol.

Détails

ID Serval
serval:BIB_AE8635494D5B
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Genetic dissection of the roles of chaperones and proteases in protein folding and degradation in the Escherichia coli cytosol.
Périodique
Molecular Microbiology
Auteur(s)
Tomoyasu T., Mogk A., Langen H., Goloubinoff P., Bukau B.
ISSN
0950-382X (Print)
ISSN-L
0950-382X
Statut éditorial
Publié
Date de publication
2001
Volume
40
Numéro
2
Pages
397-413
Langue
anglais
Résumé
We investigated the roles of chaperones and proteases in quality control of proteins in the Escherichia coli cytosol. In DeltarpoH mutants, which lack the heat shock transcription factor and therefore have low levels of all major cytosolic proteases and chaperones except GroEL and trigger factor, 5-10% and 20-30% of total protein aggregated at 30 degrees C and 42 degrees C respectively. The aggregates contained 350-400 protein species, of which 93 were identified by mass spectrometry. The aggregated protein species were similar at both temperatures, indicating that thermolabile proteins require folding assistance by chaperones already at 30 degrees C, and showed strong overlap with previously identified DnaK substrates. Overproduction of the DnaK system, or low-level production of the DnaK system and ClpB, prevented aggregation and provided thermotolerance to DeltarpoH mutants, indicating key roles for these chaperones in protein quality control and stress survival. In rpoH+ cells, DnaK depletion did not lead to protein aggregation at 30 degrees C, which is probably the result of high levels of proteases and thus suggests that DnaK is not a prerequisite for proteolysis of misfolded proteins. Lon was the most efficient protease in degrading misfolded proteins in DnaK-depleted cells. At 42 degrees C, ClpXP and Lon became essential for viability of cells with low DnaK levels, indicating synergistic action of proteases and the DnaK system, which is essential for cell growth at 42 degrees C.
Mots-clé
Bacterial Proteins/chemistry, Bacterial Proteins/metabolism, Cytosol/metabolism, Escherichia coli/enzymology, Escherichia coli/genetics, Escherichia coli Proteins, HSP70 Heat-Shock Proteins/genetics, HSP70 Heat-Shock Proteins/metabolism, Heat-Shock Proteins/genetics, Heat-Shock Proteins/metabolism, Heat-Shock Response, Molecular Chaperones/genetics, Molecular Chaperones/metabolism, Mutation, Protein Denaturation, Protein Folding, Sigma Factor, Temperature, Transcription Factors/genetics, Transcription Factors/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 16:18
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