Structure and function of the molecular chaperone Trigger Factor

Hoffmann, Anja; Bukau, Bernd; Krämer, Günter

doi:10.1016/j.bbamcr.2010.01.017

Cited by 213 publications

(246 citation statements)

References 142 publications

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“…TF is one of the three major cytosolic chaperone proteins found in all eubacteria and assists in protein folding (Hesterkamp et al 1996). This chaperone is the only ribosome-associated chaperone known in bacteria (Hoffmann et al 2010). By using mutational analysis both in vivo and in vitro, we have determined that SraL represses tig mRNA through a short stretch of complementarity in the tig 5 ′ UTR near the Shine-Dalgarno region.…”

Section: Introductionmentioning

confidence: 99%

An RpoS-dependent sRNA regulates the expression of a chaperone involved in protein folding

Silva

Ortega

Viegas

et al. 2013

RNA

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Small noncoding RNAs (sRNAs) are usually expressed in the cell to face a variety of stresses. In this report we disclose the first target for SraL (also known as RyjA), a sRNA present in many bacteria, which is highly induced in stationary phase. We also demonstrate that this sRNA is directly transcribed by the major stress σ factor σ S (RpoS) in Salmonella enterica serovar Typhimurium. We show that SraL sRNA down-regulates the expression of the chaperone Trigger Factor (TF), encoded by the tig gene. TF is one of the three major chaperones that cooperate in the folding of the newly synthesized cytosolic proteins and is the only ribosome-associated chaperone known in bacteria. By use of bioinformatic tools and mutagenesis experiments, SraL was shown to directly interact with the 5 ′ UTR of the tig mRNA a few nucleotides upstream of the Shine-Dalgarno region. Namely, point mutations in the sRNA (SraL * ) abolished the repression of tig mRNA and could only down-regulate a tig transcript target with the respective compensatory mutations. We have also validated in vitro that SraL forms a stable duplex with the tig mRNA. This work constitutes the first report of a small RNA affecting protein folding. Taking into account that both SraL and TF are very well conserved in enterobacteria, this work will have important repercussions in the field.

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Section: Introductionmentioning

confidence: 99%

An RpoS-dependent sRNA regulates the expression of a chaperone involved in protein folding

Silva

Ortega

Viegas

et al. 2013

RNA

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“…In bacteria, the ribosome-bound chaperone trigger factor (TF) plays a major role in this process. In Escherichia coli, it is believed that most nascent polypeptides emerging from the ribosome interact with TF before completing their folding (Hoffmann et al, 2010;Kramer et al, 2009). TF chaperone specifically binds to L23 protein at the polypeptide exit tunnel of active ribosomes with a 1 : 1 stoichiometry (Ferbitz et al, 2004;Kramer et al, 2002b;Patzelt et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Redundancy and specificity of multiple trigger factor chaperones in Desulfitobacteria

2011

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The ribosome-bound trigger factor (TF) chaperone assists folding of newly synthesized polypeptides and participates in the assembly of macromolecular complexes. In the present study we showed that multiple distinct TF paralogues are present in genomes of Desulfitobacteria, a bacterial genus known for its ability to grow using organohalide respiration. Two full-length TF chaperones and at least one truncated TF (lacking the N-terminal ribosome-binding domain) were identified, the latter being systematically linked to clusters of reductive dehalogenase genes encoding the key enzymes in organohalide respiration. Using a well-characterized heterologous chaperone-deficient Escherichia coli strain lacking both TF and DnaK chaperones, we demonstrated that all three TF chaperones were functional in vivo, as judged by their ability to partially suppress bacterial growth defects and protein aggregation in the absence of both major E. coli chaperones. Next, we found that the N-terminal truncated TF-like protein PceT functions as a dedicated chaperone for the cognate reductive dehalogenase PceA by solubilizing and stabilizing it in the heterologous system. Finally, we showed that PceT specifically interacts with the twin-arginine signal peptide of PceA. Taken together, our data define PceT (and more generally the new RdhT family) as a class of TF-like chaperones involved in the maturation of proteins secreted by the twin-arginine translocation pathway. INTRODUCTIONFolding of newly synthesized polypeptides in the cytosol is assisted by molecular chaperones (Hartl & Hayer-Hartl, 2009). In bacteria, the ribosome-bound chaperone trigger factor (TF) plays a major role in this process. In Escherichia coli, it is believed that most nascent polypeptides emerging from the ribosome interact with TF before completing their folding (Hoffmann et al., 2010;Kramer et al., 2009). TF chaperone specifically binds to L23 protein at the polypeptide exit tunnel of active ribosomes with a 1 : 1 stoichiometry (Ferbitz et al., 2004;Kramer et al., 2002b;Patzelt et al., 2001). Remarkably, it has been recently shown that TF cycles the ribosome on and off and that ribosome-free TF may stay bound to elongating polypeptides for a prolonged period (Kaiser et al., 2006;Rutkowska et al., 2008).In agreement with such a property, it has recently been proposed that TF participates in the post-translational assembly of large protein complexes in the cytosol (Martinez-Hackert & Hendrickson, 2009). The TF chaperone is composed of three distinct protein domains, which have been functionally and structurally determined. The Nterminal domain (NTD) consists of a ribosome-binding domain containing a conserved motif responsible for binding to ribosomal proteins (Hesterkamp et al., 1997;Kramer et al., 2002aKramer et al., , 2004. The central module in the TF structure corresponds to the C-terminal domain (CTD) and harbours the core of the chaperone activity (Genevaux et al., 2004;Kramer et al., 2004). Finally the domain encoded at the centre of the tig gene exhibits a ...

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“…Examples of all three PPIase groups are found in bacteria. Perhaps the best-studied example of a bacterial PPIase is the trigger factor Tig (a member of the FKBPs), which is found to be associated with the ribosome and assists in folding nascent peptides immediately following translation (6). Another well-studied bacterial PPIase is PrsA, a member of the parvulin family (2,5).…”

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confidence: 99%

An Intracellular Peptidyl-Prolyl cis / trans Isomerase Is Required for Folding and Activity of the Staphylococcus aureus Secreted Virulence Factor Nuclease

et al. 2017

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Staphylococcus aureus is an important human pathogen that relies on a large repertoire of secreted and cell wall-associated proteins for pathogenesis. Consequently, the ability of the organism to cause disease is absolutely dependent on its ability to synthesize and successfully secrete these proteins. In this study, we investigate the role of peptidyl-prolyl cis/trans isomerases (PPIases) on the activity of the S. aureus secreted virulence factor nuclease (Nuc). We identify a staphylococcal cyclophilin-type PPIase (PpiB) that is required for optimal activity of Nuc. Disruption of ppiB results in decreased nuclease activity in culture supernatants; however, the levels of Nuc protein are not altered, suggesting that the decrease in activity results from misfolding of Nuc in the absence of PpiB. We go on to demonstrate that PpiB exhibits PPIase activity in vitro, is localized to the bacterial cytosol, and directly interacts with Nuc in vitro to accelerate the rate of Nuc refolding. Finally, we demonstrate an additional role for PpiB in S. aureus hemolysis and demonstrate that the S. aureus parvulin-type PPIase PrsA also plays a role in the activity of secreted virulence factors. The deletion of prsA leads to a decrease in secreted protease and phospholipase activity, similar to that observed in other Gram-positive pathogens. Together, these results demonstrate, for the first time to our knowledge, that PPIases play an important role in the secretion of virulence factors in S. aureus.IMPORTANCE Staphylococcus aureus is a highly dangerous bacterial pathogen capable of causing a variety of infections throughout the human body. The ability of S. aureus to cause disease is largely due to an extensive repertoire of secreted and cell wall-associated proteins, including adhesins, toxins, exoenzymes, and superantigens. These virulence factors, once produced, are typically transported across the cell membrane by the secretory (Sec) system in a denatured state. Consequently, once outside the cell, they must refold into their active form. This step often requires the assistance of bacterial folding proteins, such as PPIases. In this work, we investigate the role of PPIases in S. aureus and uncover a cyclophilin-type enzyme that assists in the folding/refolding of staphylococcal nuclease.KEYWORDS cyclophilin, Nuc, PI-PLC, PPIase, parvulin, PpiB, PrsA, Staphylococcus aureus, nuclease, protease T he proline peptide bond is unique in nature in that both the cis and trans forms can occur in vivo, with the cis conformation existing approximately 6.5% of the time (1). In contrast, for all other naturally occurring amino acids, steric hindrance between side chains precludes the cis form and overwhelmingly favors the trans form (2). The presence of both the cis and trans forms of proline peptide bonds has important consequences for protein tertiary structure. In certain cases, the isomerization state of

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Structure and function of the molecular chaperone Trigger Factor

Cited by 213 publications

References 142 publications

An RpoS-dependent sRNA regulates the expression of a chaperone involved in protein folding

An RpoS-dependent sRNA regulates the expression of a chaperone involved in protein folding

Redundancy and specificity of multiple trigger factor chaperones in Desulfitobacteria

An Intracellular Peptidyl-Prolyl cis / trans Isomerase Is Required for Folding and Activity of the Staphylococcus aureus Secreted Virulence Factor Nuclease

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