In vivo analysis of the overlapping functions of DnaK and trigger factor

Trigger factor (TF) is a ribosome‐bound protein that combines catalysis of peptidyl‐prolyl isomerization and chaperone‐like activities in Escherichia coli. TF was shown to cooperate with the DnaK (Hsp70) chaperone machinery in the folding of newly synthesized proteins, and the double deletion of the...

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Bibliographic Details
Published in:EMBO reports 2004-02, Vol.5 (2), p.195-200
Main Authors: Genevaux, Pierre, Keppel, France, Schwager, Françoise, Langendijk-Genevaux, Petra S, Hartl, F Ulrich, Georgopoulos, Costa
Format: Article
Language:English
Subjects:
Chaperonin 10 - genetics
Chaperonin 10 - metabolism
Chaperonin 60 - genetics
Chaperonin 60 - metabolism
Escherichia coli
Escherichia coli Proteins - genetics
Escherichia coli Proteins - metabolism
Genetic Complementation Test
Heat-Shock Proteins - genetics
Heat-Shock Proteins - metabolism
Heat-Shock Response - genetics
HSP40 Heat-Shock Proteins
HSP70 Heat-Shock Proteins - genetics
HSP70 Heat-Shock Proteins - metabolism
Molecular Chaperones - genetics
Molecular Chaperones - metabolism
Peptidylprolyl Isomerase - genetics
Peptidylprolyl Isomerase - metabolism
Porins - genetics
Porins - metabolism
Protein Folding
Protein Structure, Tertiary - genetics
Scientific Report
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Summary:Trigger factor (TF) is a ribosome‐bound protein that combines catalysis of peptidyl‐prolyl isomerization and chaperone‐like activities in Escherichia coli. TF was shown to cooperate with the DnaK (Hsp70) chaperone machinery in the folding of newly synthesized proteins, and the double deletion of the corresponding genes (tig and dnaK) exhibited synthetic lethality. We used a detailed genetic approach to characterize various aspects of this functional cooperation in vivo. Surprisingly, we showed that under specific growth conditions, one can delete both dnaK and tig, indicating that bacterial survival can be maintained in the absence of these two major cytosolic chaperones. The strain lacking both DnaK and TF exhibits a very narrow temperature range of growth and a high level of aggregated proteins when compared to either of the single mutants. We found that, in the absence of DnaK, both the N‐terminal ribosome‐binding domain and the C‐terminal domain of unknown function are essential for TF chaperone activity. In contrast, the central PPIase domain is dispensable. Taken together, our data indicate that under certain conditions, folding of newly synthesized proteins in E. coli is not totally dependent on an interaction with either TF and/or DnaK, and suggest that additional chaperones may be involved in this essential process.
ISSN:1469-221X
1469-3178
1469-221X
DOI:10.1038/sj.embor.7400067