Influence of tat mutations on the ribose-binding protein translocation in Escherichia coli

Pradel, Nathalie; Santini, Claire‐Lise; Ye, Changyun; Fevat, Léna M.S.; Gérard, Fabien; Alami, Mériem; Wu, Long‐Fei

doi:10.1016/s0006-291x(03)01043-x

Cited by 18 publications

(11 citation statements)

References 23 publications

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“…The twin arginine signal peptides resemble Sec-dependent signal peptides considering their overall structures but possess a twin arginine motif in the N region, a weakly hydrophobic H region, and a Sec-avoidance signal composed of basic residues around the H region. Increasing evidence suggests that signal peptides without the conserved RR motifs can also mediate TAT pathway translocation (15,16,25). Therefore, the criterion of the presence of the twin arginine motif in the signal peptide seems not to be sufficient for identifying the proteins that are exported by the TAT system.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, the criterion of the presence of the twin arginine motif in the signal peptide seems not to be sufficient for identifying the proteins that are exported by the TAT system. Interestingly, Stx1B possesses a double lysine motif in the signal peptide, which is compatible with a TAT-dependent translocation under certain contexts (16,25). It is possible that the TAT pathway might be involved, directly or indirectly, in the translocation of virulence factors synthesized with the signal peptide without the twin arginine motif in E. coli O157:H7.…”

Section: Resultsmentioning

confidence: 99%

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Contribution of the Twin Arginine Translocation System to the Virulence of Enterohemorrhagic Escherichia coli O157:H7

Pradel

Livrelli³

et al. 2003

Infect Immun

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Shiga toxin-producing Escherichia coli O157:H7 is a major food-borne infectious pathogen. In order to analyze the contribution of the twin arginine translocation (TAT) system to the virulence of E. coli O157:H7, we deleted the tatABC genes of the O157:H7 EDL933 reference strain. The mutant displayed attenuated toxicity on Vero cells and completely lost motility on soft agar plates. Further analyses revealed that the ⌬tatABC mutation impaired the secretion of the Shiga toxin 1 (Stx1) and abolished the synthesis of H7 flagellin, which are two major known virulence factors of enterohemorrhagic E. coli O157:H7. Expression of the EDL933 stxAB 1 genes in E. coli K-12 conferred verotoxicity on this nonpathogenic strain. Remarkably, cytotoxicity assay and immunoblot analysis showed, for the first time, an accumulation of the holotoxin complex in the periplasm of the wild-type strain and that a much smaller amount of StxA 1 and reduced verotoxicity were detected in the ⌬tatC mutant cells. Together, these results establish that the TAT system of E. coli O157:H7 is an important virulence determinant of this enterohemorrhagic pathogen.Bacteria export numerous proteins across the cytoplasmic membrane via either the Sec machinery (26) or the twin arginine translocation (TAT) (also called membrane targeting and translocation [MTT]) system (41). The TAT system is different from the Sec pathway because of its unusual ability to transport folded proteins and even enzyme complexes into the periplasm. Most of the TAT substrates are cofactor-containing enzymes taking part in oxidation-reduction systems involved in energy conservation under anaerobic conditions. The essential tat genes are found in most bacterial genomes, including the pathogens Helicobacter pylori, Yersinia pestis, Vibrio cholerae, Salmonella enterica subsp. enterica serovar Typhi, Haemophilus influenzae, Mycobacterium tuberculosis, Staphylococcus aureus, and Pseudomonas aeruginosa (41). The functionality of the TAT pathway has been reported for Escherichia coli (32, 40), Zymomonas mobilis (12), Ralstonia eutropha (5), Bacillus subtilis (17), Pseudomonas stutzeri (14), and Streptomyces lividans (33). It has been demonstrated that the P. aeruginosa TAT system operates in parallel with the Sec machinery in the secretion of virulence factors via the type II secretion pathway (38). Further investigation has shown that the TAT system of P. aeruginosa contributes to virulence through the secretion of various factors associated with either pathogenesis or stress response (23). Recently, Ding and Christie reported that the TAT system is an important virulence determinant of the phytopathogen Agrobacterium tumefaciens (10).Widespread E. coli is a major component of the normal intestinal flora of humans and other mammals and is usually harmless to the host. However, some specific E. coli strains represent primary pathogens with an enhanced potential to cause disease. Shiga toxin-or verotoxin-producing E. coli (STEC or VTEC, respectively) causes not only a broad range of sympt...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Contribution of the Twin Arginine Translocation System to the Virulence of Enterohemorrhagic Escherichia coli O157:H7

Pradel

Livrelli³

et al. 2003

Infect Immun

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“…The preparation of spheroplasts was described previously (21). The fractions were analyzed by immunoblot with anti-RBP or anti-GroEL sera as described previously (19,20).…”

Section: Methodsmentioning

confidence: 99%

Bactericidal Activity of Colicin V Is Mediated by an Inner Membrane Protein, SdaC, of Escherichia coli

Gérard

Pradel

2005

J Bacteriol

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Colicin V (ColV) is a peptide antibiotic that kills sensitive cells by disrupting their membrane potential once it gains access to the inner membrane from the periplasmic face. Recently, we constructed a translocation suicide probe, RR-ColV, that is translocated into the periplasm via the TAT pathway and thus kills the host cells. In this study, we obtained an RR-ColV-resistant mutant by using random Tn10 transposition mutagenesis. Sequencing analysis revealed that the mutant carried a Tn10 insertion in the sdaC (also called dcrA) gene, which is involved in serine uptake and is required for C1 phage adsorption. ColV activity was detected both in the cytoplasm and in the periplasm of this mutant, indicating that RR-ColV was translocated into the periplasm but failed to interact with the inner membrane. The sdaC::Tn10 mutant was resistant only to ColV and remained sensitive to colicins Ia, E3, and A. Most importantly, the sdaC::Tn10 mutant was killed when ColV was anchored to the periplasmic face of the inner membrane by fusion to EtpM, a type II integral membrane protein. Taken together, these results suggest that the SdaC/DcrA protein serves as a specific inner membrane receptor for ColV.

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“…For the other Sec pathway substrates corresponding to the alkaline N-termini of the Tat signal sequences, the expression of the ribose-binding protein N-terminal sequence MNMKK (pI 10.55) is significantly reduced in the periplasm of tat mutants, but is restored by trans expression of the tatABC genes (Pradel et al, 2003). Additionally, the activity of Stenotrophomonas maltophilia L2 β-lactamase, which has the N-terminal sequence MLARRR (pI 12.80) is much lower in a ΔtatC mutant than in a secY-cs mutant (Pradel et al, 2009).…”

Section: Resultsmentioning

confidence: 99%

Novel GFP Expression Using a Short N-Terminal Polypeptide through the Defined Twin-Arginine Translocation (Tat) Pathway

Lee

Han

Kim

et al. 2011

Molecules and Cells

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Escherichia coli is frequently used as a convenient host organism for soluble recombinant protein expression. However, additional strategies are needed for proteins with complex folding characteristics. Here, we suggested that the acidic, neutral, and alkaline isoelectric point (pI) range curves correspond to the channels of the E. coli type-II cytoplasmic membrane translocation (periplasmic translocation) pathways of twin-arginine translocation (Tat), Yid, and general secretory pathway (Sec), respectively, for unfolded and folded target proteins by examining the characteristic pI values of the N-termini of the signal sequences or the leader sequences, matching with the known diameter of the translocation channels, and analyzing the N-terminal pI value of the signal sequences of the Tat substrates. To confirm these proposed translocation pathways, we investigated the soluble expression of the folded green fluorescent protein (GFP) with short N-terminal polypeptides exhibiting pI and hydrophilicity separately or collectively. This, in turn, revealed the existence of an anchor function with a specific directionality based on the N-terminal pI value (termed as N-terminal pI-specific directionality) and distinguished the presence of the E. coli type-II cytoplasmic membrane translocation pathways of Tat, Yid, and Sec for the unfolded and folded target proteins. We concluded that the pI value and hydrophilicity of the short N-terminal polypeptide, and the total translational efficiency of the target proteins based on the ΔG RNA value of the N-terminal coding regions are important factors for promoting more efficient translocation (secretion) through the largest diameter of the Tat channel. These results show that the short N-terminal polypeptide could substitute for the Tat signal sequence with improved efficiency.

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Influence of tat mutations on the ribose-binding protein translocation in Escherichia coli

Cited by 18 publications

References 23 publications

Contribution of the Twin Arginine Translocation System to the Virulence of Enterohemorrhagic Escherichia coli O157:H7

Contribution of the Twin Arginine Translocation System to the Virulence of Enterohemorrhagic Escherichia coli O157:H7

Bactericidal Activity of Colicin V Is Mediated by an Inner Membrane Protein, SdaC, of Escherichia coli

Novel GFP Expression Using a Short N-Terminal Polypeptide through the Defined Twin-Arginine Translocation (Tat) Pathway

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