Bacterial Hsp90 Facilitates the Degradation of Aggregation-Prone Hsp70–Hsp40 Substrates

Bruno Fauvet, Andrija Finka, Marie Pierre Castanié-Cornet, Anne Marie Cirinesi, Pierre Genevaux, Manfredo Quadroni, Pierre Goloubinoff*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


In eukaryotes, the 90-kDa heat shock proteins (Hsp90s) are profusely studied chaperones that, together with 70-kDa heat shock proteins (Hsp70s), control protein homeostasis. In bacteria, however, the function of Hsp90 (HtpG) and its collaboration with Hsp70 (DnaK) remains poorly characterized. To uncover physiological processes that depend on HtpG and DnaK, we performed comparative quantitative proteomic analyses of insoluble and total protein fractions from unstressed wild-type (WT) Escherichia coli and from knockout mutants ΔdnaKdnaJ (ΔKJ), ΔhtpG (ΔG), and ΔdnaKdnaJΔhtpG (ΔKJG). Whereas the ΔG mutant showed no detectable proteomic differences with wild-type, ΔKJ expressed more chaperones, proteases and ribosomes and expressed dramatically less metabolic and respiratory enzymes. Unexpectedly, we found that the triple mutant ΔKJG showed higher levels of metabolic and respiratory enzymes than ΔKJ, suggesting that bacterial Hsp90 mediates the degradation of aggregation-prone Hsp70–Hsp40 substrates. Further in vivo experiments suggest that such Hsp90-mediated degradation possibly occurs through the HslUV protease.

Original languageEnglish
Article number653073
JournalFrontiers in Molecular Biosciences
StatePublished - 15 Apr 2021
Externally publishedYes


FundersFunder number
Swiss State Secretariat for Education Research and Innovation
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung140512/1, C15.0042, 31003A_156948
Université de Lausanne


    • DnaJ
    • DnaK
    • HslV
    • HtpG
    • chaperones
    • proteostasis


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