The TatA component of the twin-arginine protein transport system forms channel complexes of variable diameter

Gohlke, U.; Pullan, Lee; McDevitt, Christopher A.; Porcelli, Ida; Leeuw, Erik de; Palmer, Tracy; Saibil, Helen R.; Berks, Ben C.

doi:10.1073/pnas.0503558102

Cited by 243 publications

(288 citation statements)

References 31 publications

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“…Studies in E. coli have demonstrated that TatA can exist in complexes with TatB and TatBC and as a separate TatA homooligomer (25)(26)(27)(28). In addition, the TatA protein itself may form the actual pore for protein secretion (29). Based on this information, the simplest explanation is that the unprocessed form of TatA is unable to interact with itself or one or more of the Tat proteins, possibly because of an unfavorable conformation.…”

Section: Discussionmentioning

confidence: 99%

Rhomboid protease AarA mediates quorum-sensing in Providencia stuartii by activating TatA of the twin-arginine translocase

Stevenson

Střı́šovský

Clemmer

et al. 2007

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

147

139

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The Providencia stuartii AarA protein is a member of the rhomboid family of intramembrane serine proteases and is required for the production of an unknown quorum-sensing molecule. In a screen to identify rhomboid-encoding genes from Proteus mirabilis, tatA was identified as a multicopy suppressor and restored extracellular signal production as well as complementing all other phenotypes of a Prov. stuartii aarA mutant. TatA is a component of the twin-arginine translocase (Tat) protein secretion pathway and likely forms a secretion pore. By contrast, the native tatA gene of Prov. stuartii in multicopy did not suppress an aarA mutation. We find that TatA in Prov. stuartii has a short N-terminal extension that was atypical of TatA proteins from most other bacteria. This extension was proteolytically removed by AarA both in vivo and in vitro. A Prov. stuartii TatA protein missing the first 7 aa restored the ability to rescue the aarA-dependent phenotypes. To verify that loss of the Tat system was responsible for the various phenotypes exhibited by an aarA mutant, a tatC-null allele was constructed. The tatC mutant exhibited the same phenotypes as an aarA mutant and was epistatic to aarA. These data provide a molecular explanation for the requirement of AarA in quorum-sensing and uncover a function for the Tat protein export system in the production of secreted signaling molecules. Finally, TatA represents a validated natural substrate for a prokaryotic rhomboid protease.

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Section: Discussionmentioning

confidence: 99%

Rhomboid protease AarA mediates quorum-sensing in Providencia stuartii by activating TatA of the twin-arginine translocase

Stevenson

Střı́šovský

Clemmer

et al. 2007

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

147

139

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“…The consensus motif is always located at the junction between the n and h regions (2). Precursors bearing Tat signal peptides are transported by a membrane embedded export apparatus comprising a signal peptide recognition complex (4) and a protein-conducting channel (5). The physiological role of the Tat system is to transport fully folded proteins (1,6,7), and pathogenic bacteria deficient in Tat transport demonstrate reduced virulence, which has led to consideration of this system as a target for novel antiinfectives (8).…”

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confidence: 99%

Structural diversity in twin-arginine signal peptide-binding proteins

Maillard

Spronk

Buchanan

et al. 2007

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

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The twin-arginine transport (Tat) system is dedicated to the translocation of folded proteins across the bacterial cytoplasmic membrane. Proteins are targeted to the Tat system by signal peptides containing a twin-arginine motif. In Escherichia coli, many Tat substrates bind redox-active cofactors in the cytoplasm before transport. Coordination of cofactor insertion with protein export involves a ''Tat proofreading'' process in which chaperones bind twin-arginine signal peptides, thus preventing premature export. The initial Tat signal-binding proteins described belonged to the TorD family, which are required for assembly of N-and S-oxide reductases. Here, we report that E. coli NapD is a Tat signal peptide-binding chaperone involved in biosynthesis of the Tatdependent nitrate reductase NapA. NapD binds tightly and specifically to the NapA twin-arginine signal peptide and suppresses signal peptide translocation activity such that transport via the Tat pathway is retarded. High-resolution, heteronuclear, multidimensional NMR spectroscopy reveals the 3D solution structure of NapD. The chaperone adopts a ferredoxin-type fold, which is completely distinct from the TorD family. Thus, NapD represents a new family of twin-arginine signal-peptide-binding proteins.metalloenzyme biosynthesis ͉ molecular chaperone ͉ NMR solution structure ͉ protein-protein interactions ͉ twin-arginine transport pathway

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“…Additional evidence suggests that the Tat channel faces considerably greater mechanistic challenges than does the Sec channel (Gohlke et al, 2005). Studies in E. coli demonstrated that the Tat system consists, at least, of four integral membrane proteins: TatA, TatB, TatC, and TatE (Sargent et al, 1999).…”

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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The TatA component of the twin-arginine protein transport system forms channel complexes of variable diameter

Cited by 243 publications

References 31 publications

Rhomboid protease AarA mediates quorum-sensing in Providencia stuartii by activating TatA of the twin-arginine translocase

Rhomboid protease AarA mediates quorum-sensing in Providencia stuartii by activating TatA of the twin-arginine translocase

Structural diversity in twin-arginine signal peptide-binding proteins

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

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