GroE is vital for cell-wall synthesis

McLennan, Neil; Masters, Millicent

doi:10.1038/32317

Cited by 98 publications

(189 citation statements)

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“…Further characterization of the most defective mutant revealed that it has almost normal binding to chaperones and RNA polymerase and is competent for chaperone-mediated inactivation in vitro. We suggest that the mutants identify a regulatory step downstream of chaperone binding that is required for both inactivation and degradation of 32 .…”

mentioning

confidence: 99%

“…Understanding this mode of regulation is central to our understanding of protein quality control as well as cellular stress responses. Here, we report the determinants required for chaperone regulation of 32 , the heat shock transcription factor in Escherichia coli (10)(11)(12). 32 regulon members control both the activity and stability of 32 .…”

mentioning

confidence: 99%

“…Here, we report the determinants required for chaperone regulation of 32 , the heat shock transcription factor in Escherichia coli (10)(11)(12). 32 regulon members control both the activity and stability of 32 . The DnaK/J/GrpE and GroEL/S chaperone machines each constitute a negative feedback loop that couples 32 activity to cellular protein folding state: overexpression of either chaperone machine decreases 32 activity; conversely, chaperone depletion or overexpression of chaperone substrates increases 32 activity (13)(14)(15)(16).…”

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confidence: 99%

“…In Escherichia coli, expression of chaperones and proteases is positively regulated by 32 . Chaperone-mediated negative feedback control of 32 activity allows this transcription factor to sense the cellular folding state.…”

mentioning

confidence: 99%

“…32 regulon members control both the activity and stability of 32 . The DnaK/J/GrpE and GroEL/S chaperone machines each constitute a negative feedback loop that couples 32 activity to cellular protein folding state: overexpression of either chaperone machine decreases 32 activity; conversely, chaperone depletion or overexpression of chaperone substrates increases 32 activity (13)(14)(15)(16). The chaperones are likely to act directly on 32 because they bind to 32 and inhibit its activity in a purified in vitro transcription system (17)(18)(19).…”

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Analysis of σ ³² mutants defective in chaperone-mediated feedback control reveals unexpected complexity of the heat shock response

Yura

Guisbert²,

Poritz

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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Protein quality control is accomplished by inducing chaperones and proteases in response to an altered cellular folding state. In Escherichia coli, expression of chaperones and proteases is positively regulated by 32 . Chaperone-mediated negative feedback control of 32 activity allows this transcription factor to sense the cellular folding state. We identified point mutations in 32 altered in feedback control. Surprisingly, such mutants are resistant to inhibition by both the DnaK/J and GroEL/S chaperones in vivo and also show dramatically increased stability. Further characterization of the most defective mutant revealed that it has almost normal binding to chaperones and RNA polymerase and is competent for chaperone-mediated inactivation in vitro. We suggest that the mutants identify a regulatory step downstream of chaperone binding that is required for both inactivation and degradation of 32 .heat shock transcription factor ͉ proteolysis ͉ GroEL ͉ DnaK ͉ stress response T he heat shock response is a major homeostatic mechanism for controlling the state of protein folding and degradation in all cells (1-3). Upon heat stress, a set of highly conserved heat shock proteins (hsps), including chaperones and proteases, is rapidly and transiently induced. Hsps maintain optimal states of protein folding and turnover during normal growth and also minimize cellular damage from stress-induced protein misfolding and aggregation (4, 5). The level of hsps is controlled primarily by heat shock transcription factors that sense the cellular folding environment through negative feedback control mediated by chaperones (6-9). Understanding this mode of regulation is central to our understanding of protein quality control as well as cellular stress responses. Here, we report the determinants required for chaperone regulation of 32 , the heat shock transcription factor in Escherichia coli (10-12).32 regulon members control both the activity and stability of 32 . The DnaK/J/GrpE and GroEL/S chaperone machines each constitute a negative feedback loop that couples 32 activity to cellular protein folding state: overexpression of either chaperone machine decreases 32 activity; conversely, chaperone depletion or overexpression of chaperone substrates increases 32 activity (13-16). The chaperones are likely to act directly on 32 because they bind to 32 and inhibit its activity in a purified in vitro transcription system (17-19). Regulated degradation of 32 is mediated by the FtsH protease and facilitated by DnaK/J/GrpE and GroEL/S in vivo, but this process has not been completely recapitulated in vitro, where degradation of 32 by FtsH is slow and not facilitated by chaperones (20,21).We selected and characterized feedback-resistant mutants of 32 . The residues altered by the mutations map to a small patch in 32 . Surprisingly, most mutants simultaneously diminished all three negative feedback loops operative in vivo; the most severe mutant essentially eliminated chaperone-mediated activity control and degradation by FtsH protease. In stri...

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Analysis of σ ³² mutants defective in chaperone-mediated feedback control reveals unexpected complexity of the heat shock response

Yura

Guisbert²,

Poritz

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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Identification of novel in vivo obligate GroEL/ES substrates based on data from a cell‐free proteomics approach

2016

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Edited by Alfonso ValenciaChaperones are essential to maintain the proper folding of various proteins in vivo. The Escherichia coli chaperonin GroEL/GroES (GroE) is one of the best-studied chaperones, and its in vivo substrates have been identified, mainly by mass spectrometry-based proteomic studies. Here, we newly identified 20 in vivo obligate GroE substrates with the aid of data from an in vitro comprehensive analysis. The newly identified substrates have similar physicochemical properties to the known substrates, but their expression levels in vivo were significantly lower. Information from the in vitro comprehensive analysis has the potential to compensate for limitations of the MS-based proteomic approaches.

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Towards Functional Orthogonalisation of Protein Complexes: Individualisation of GroEL Monomers Leads to Distinct Quasihomogeneous Single Rings

et al. 2013

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The essential molecular chaperonin GroEL is an example of a functionally highly versatile cellular machine with a wide variety of in vitro applications ranging from protein folding to drug release. Directed evolution of new functions for GroEL is considered difficult, due to its structure as a complex homomultimeric double ring and the absence of obvious molecular engineering strategies. In order to investigate the potential to establish an orthogonal GroEL system in Escherichia coli, which might serve as a basis for GroEL evolution, we first successfully individualised groEL genes by inserting different functional peptide tags into a robustly permissive site identified by transposon mutagenesis. These peptides allowed fundamental aspects of the intracellular GroEL complex stoichiometry to be studied and revealed that GroEL single-ring complexes, which assembled in the presence of several functionally equivalent but biochemically distinct monomers, each consist almost exclusively of only one type of monomer. At least in the case of GroEL, individualisation of monomers thus leads to individualisation of homomultimeric protein complexes, effectively providing the prerequisites for evolving an orthogonal intracellular GroEL folding machine.

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GroE is vital for cell-wall synthesis

Cited by 98 publications

References 3 publications

Analysis of σ ³² mutants defective in chaperone-mediated feedback control reveals unexpected complexity of the heat shock response

Analysis of σ ³² mutants defective in chaperone-mediated feedback control reveals unexpected complexity of the heat shock response

Identification of novel in vivo obligate GroEL/ES substrates based on data from a cell‐free proteomics approach

Towards Functional Orthogonalisation of Protein Complexes: Individualisation of GroEL Monomers Leads to Distinct Quasihomogeneous Single Rings

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GroE is vital for cell-wall synthesis

Cited by 98 publications

References 3 publications

Analysis of σ 32 mutants defective in chaperone-mediated feedback control reveals unexpected complexity of the heat shock response

Analysis of σ 32 mutants defective in chaperone-mediated feedback control reveals unexpected complexity of the heat shock response

Identification of novel in vivo obligate GroEL/ES substrates based on data from a cell‐free proteomics approach

Towards Functional Orthogonalisation of Protein Complexes: Individualisation of GroEL Monomers Leads to Distinct Quasihomogeneous Single Rings

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Analysis of σ ³² mutants defective in chaperone-mediated feedback control reveals unexpected complexity of the heat shock response

Analysis of σ ³² mutants defective in chaperone-mediated feedback control reveals unexpected complexity of the heat shock response