Specificity of Signal Peptide Recognition in Tat-Dependent Bacterial Protein Translocation

Blaudeck, Natascha; Sprenger, Georg A.; Freudl, Roland; Wiegert, Thomas

doi:10.1128/jb.183.2.604-610.2001

Cited by 63 publications

(33 citation statements)

References 50 publications

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“…Our inability to detect significant levels of ss-Sec-ЈBlaC fusion proteins by nitrocefin analysis of whole-cell extracts may reflect rapid degradation of fusions incompatible with export from the cytoplasm, as this is a common fate of nonexported Tat substrates (8,17). An alternate possibility is that the ssSec-ЈBlaC fusions are translocated by the Sec pathway in an unfolded state and that the resulting exported ЈBlaC is enzymatically inactive due to improper folding.…”

Section: Discussionmentioning

confidence: 77%

The Twin-Arginine Translocation Pathway of Mycobacterium smegmatis Is Functional and Required for the Export of Mycobacterial β-Lactamases

et al. 2005

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Tuberculosis, caused by the bacillus Mycobacterium tuberculosis, remains a global health problem accounting for over two million deaths annually (23). The ability to survive in host phagocytes is a poorly understood virulence property of M. tuberculosis. The M. tuberculosis proteins exported to the bacterial cell surface or secreted by the bacillus are ideally positioned to interact with host cell components and include virulence factors that promote intracellular survival.

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Section: Discussionmentioning

confidence: 77%

The Twin-Arginine Translocation Pathway of Mycobacterium smegmatis Is Functional and Required for the Export of Mycobacterial β-Lactamases

et al. 2005

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“…There is also some evidence that the Tat machinery from different bacteria may show specificity towards cognate signal peptides. For example, although the glucose-fructose oxidoreductase (GFOR) of Z. mobilis is a Tat substrate in its native organism, it is not exported when heterologously expressed in E. coli (Blaudeck et al, 2001). However, when the native GFOR signal sequence is precisely replaced by that of E. coli TorA, the hybrid protein is exported by E. coli in a Tat-dependent manner (Blaudeck et al, 2001).…”

Section: The Tat Signal Peptidementioning

confidence: 99%

Moving folded proteins across the bacterial cell membrane

Palmer

Berks

2003

Microbiology

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The Tat protein export system is located in the bacterial cytoplasmic membrane and operates in parallel to the well-known Sec pathway. While the Sec system only transports unstructured substrates, the function of the Tat pathway is to translocate folded proteins. The Tat translocase thus faces the formidable challenge of moving structured macromolecular substrates across the bacterial cytoplasmic membrane without rendering the membrane freely permeable to protons and other ions. The substrates of the Tat pathway are often proteins that bind cofactor molecules in the cytoplasm, and are thus folded, prior to export. Such periplasmic cofactor-containing proteins are essential for most types of bacterial respiratory and photosynthetic energy metabolism. In addition, the Tat pathway is involved in outer membrane biosynthesis and in bacterial pathogenesis. Substrates are targeted to the Tat pathway by amino-terminal signal sequences harbouring consecutive, essentially invariant, arginine residues, and movement of proteins through the Tat system is energized by the transmembrane proton electrochemical gradient. The TatA protein probably forms the transport channel while the TatBC proteins act as a receptor complex that recognizes the signal peptide of the substrate protein.

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“…Several studies examining the compatibility between Tat signal sequences from heterologous hosts and the E. coli Tat transport system have been carried out. Examples have been found for full recognition of the heterologous signal sequence (32), leading to Tat transport of the substrate as well as noncompatibility between the signal sequence and E. coli Tat, leading to a sequestration of the Tat substrate in the cytosol (4,35). Since our findings suggest that the PlcH Tat signal sequence resembles a typical E. coli Tat signal sequence, we tested whether the E. coli Tat translocation system can recognize and translocate the P. aeruginosa PlcH protein.…”

Section: Resultsmentioning

confidence: 99%

“…In addition to the residues within the consensus sequence of the leader peptide, basic residues at the C terminus of the leader sequence have been shown to play a role in the secretion of Tat substrates both in thylakoids and bacteria (4,5,15,26). These residues have been found to function, not in targeting to the Tat translocon, but in preventing the functional interaction of a Tat substrate with the Sec apparatus (5,3).…”

Section: Discussionmentioning

confidence: 99%

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Role of the Pseudomonas aeruginosa PlcH Tat Signal Peptide in Protein Secretion, Transcription, and Cross-Species Tat Secretion System Compatibility

et al. 2006

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The secretion of PlcH and its homolog PlcN of Pseudomonas aeruginosa through the inner membrane depends upon a functional twin arginine translocase (Tat) system and a Tat signal sequence. Conserved twin arginine (Arg) residues within the Tat signal sequence consensus motif (S/TRRxFLK) are considered essential for the secretion of Tat substrates, but some exceptions (e.g., Lys and Arg) to the twin Arg residues in this motif have been noted. The roles of all three Arg residues within the PlcH RRRTFLK consensus motif were examined. Data are presented which indicate that Arg-9 and Arg-10 are essential for PlcH secretion across the inner membrane, but the mutation of Arg-8 (e.g., to Ala or Ser) had no observable effect on the localization of PlcH. In the signal sequence of PlcH and in all of its homologs in other bacteria, there are basic amino acid residues (Arg, Lys, and Gln) immediately adjacent to the signal peptidase cleavage site (Ala-X-Ala) that are not seen in Sec-dependent signal sequences. The mutation of these basic residues to Ala caused slightly decreased levels of extracellular PlcH, but normal localization was still observed. Deletion of the entire Tat signal sequence of PlcH not only resulted in the absence of detectable extracellular PlcH activity and protein but also caused a substantial decrease in the detectable level of plcH mRNA. Finally, data are presented which indicate that P. aeruginosa PlcH exhibits cross-species compatibility with the Escherichia coli Tat secretion machinery, but only when the E. coli Tat machinery is expressed in a P. aeruginosa host.

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Specificity of Signal Peptide Recognition in Tat-Dependent Bacterial Protein Translocation

Cited by 63 publications

References 50 publications

The Twin-Arginine Translocation Pathway of Mycobacterium smegmatis Is Functional and Required for the Export of Mycobacterial β-Lactamases

The Twin-Arginine Translocation Pathway of Mycobacterium smegmatis Is Functional and Required for the Export of Mycobacterial β-Lactamases

Moving folded proteins across the bacterial cell membrane

Role of the Pseudomonas aeruginosa PlcH Tat Signal Peptide in Protein Secretion, Transcription, and Cross-Species Tat Secretion System Compatibility

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