Contribution of the Twin Arginine Translocation system to the exoproteome of Pseudomonas aeruginosa

Abstract

The opportunistic pathogen Pseudomonas aeruginosa uses secretion systems to deliver exoproteins into the environment. These exoproteins contribute to bacterial survival, adaptation, and virulence. The Twin arginine translocation (Tat) export system enables the export of folded proteins into the periplasm, some of which can then be further secreted outside the cell. However, the full range of proteins that are conveyed by Tat is unknown, despite the importance of Tat for the adaptability and full virulence of P. aeruginosa. In this work, we explored the P. aeruginosa Tat-dependent exoproteome under phosphate starvation by two-dimensional gel analysis. We identified the major secreted proteins and new Tat-dependent exoproteins. These exoproteins were further analyzed by a combination of in silico analysis, regulation studies, and protein localization. Altogether we reveal that the absence of the Tat system significantly affects the composition of the exoproteome by impairing protein export and affecting gene expression. Notably we discovered three new Tat exoproteins and one novel type II secretion substrate. Our data also allowed the identification of two new start codons highlighting the importance of protein annotation for subcellular predictions. The new exoproteins that we identify may play a significant role in P. aeruginosa pathogenesis, host interaction and niche adaptation.

Secreted Phosphatase and Deoxyribonuclease Are Required by Pseudomonas aeruginosa To Defend against Neutrophil Extracellular Traps

“…Interestingly, the upstream open reading frame (ORF) PA3910 is predicted to encode an alkaline phosphatase, EddA, and shares a promoter with eddB, forming a bicistronic operon (16,29). EddA contains a predicted signal peptide for the twin-arginine translation (TAT) pathway, which transports folded proteins across the inner membrane, and uses the Xcp pathway to cross the outer membrane (30). Alkaline phosphatase proteins fall into 3 groups: PhoX, PhoA, and PhoD-type phosphatases (31).…”

“…EddA shares ϳ49% homology with Bacillus subtilis PhoD, the archetypal secreted alkaline phosphatase (32). Interestingly, PhoD phosphatases possess both monoesterase as well as phosphodiesterase (PDase) activities (30,31). Moreover, EddA homologs, such as the Zymomonas mobilis CP4 PhoD alkaline phosphatase, have been shown to hydrolyze nucleotides more effectively than sugar phosphates (33).…”

Unraveling the Self-Assembly of the Pseudomonas aeruginosa XcpQ Secretin Periplasmic Domain Provides New Molecular Insights into Type II Secretion System Secreton Architecture and Dynamics

“…(B) Coomassie blue-stained gel of extracellular protein samples from various P. aeruginosa strains grown in the presence (+) or not (-) of 1 mM reducing agent dithiothreitol (DTT). The five Xcp T2SS effectors PrpL, elastase LasB, chitin binding protein D (CbpD), aminopeptidase PaAP, and metalloprotease ImpA ( 43 ) are indicated by black diamonds; the secreted effectors of the Hxc T2SS alkaline phosphatase LapA ( 44 ) and the T1SS alkaline protease AprA ( 45 ) are indicated in gray by a dot and a star, respectively. Molecular mass markers (in kilodaltons) are indicated on the left.…”

The Tat Substrate SufI Is Critical for the Ability of Yersinia pseudotuberculosis To Cause Systemic Infection

“…tomato DC3000 (11), Burkholderia thailandensis (12), Salmonella enterica serovar Enteritidis (13), Campylobacter jejuni (14), and Vibrio cholerae (15). In these pathogens, mutants lacking a functional Tat exhibit different virulence-related phenotypes, such as decreased motility, toxin production, and biofilm formation; sensitivity to detergents and bile; and decreased T3SS secretion, cell growth, and division (16,17). In many cases, these Tat-related phenotypes are the result of indirect effects on regulation/expression.…”