The Pseudomonas aeruginosa patatin-like protein PlpD is the archetype of a novel Type V secretion system

Authors

  • Richard Salacha,

    1. Laboratoire d'Ingénierie des Systèmes Macromoléculaires, CNRS-Aix Marseille Université, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
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  • Filip Kovačić,

    1. Institute for Molecular Enzyme Technology, Heinrich-Heine-University Duesseldorf at FZ-Juelich Stetternicher Forst, D-52426 Juelich, Germany.
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  • Céline Brochier-Armanet,

    1. Laboratoire de Chimie Bactérienne, CNRS-Aix Marseille Université, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
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  • Susanne Wilhelm,

    1. Institute for Molecular Enzyme Technology, Heinrich-Heine-University Duesseldorf at FZ-Juelich Stetternicher Forst, D-52426 Juelich, Germany.
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  • Jan Tommassen,

    1. Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, 3584 CH Utrecht, the Netherlands.
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  • Alain Filloux,

    1. Laboratoire d'Ingénierie des Systèmes Macromoléculaires, CNRS-Aix Marseille Université, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
    2. Centre for Molecular Microbiology and Infection, Division of Cell and Molecular Biology, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
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  • Romé Voulhoux,

    1. Laboratoire d'Ingénierie des Systèmes Macromoléculaires, CNRS-Aix Marseille Université, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
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  • Sophie Bleves

    Corresponding author
    1. Laboratoire d'Ingénierie des Systèmes Macromoléculaires, CNRS-Aix Marseille Université, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
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E-mail bleves@ifr88.cnrs-mrs.fr; Tel. (+33) 491164126; Fax (+33) 491712124.

Summary

We discovered a novel secreted protein by Pseudomonas aeruginosa, PlpD, as a member of the bacterial lipolytic enzyme family of patatin-like proteins (PLPs). PlpD is synthesized as a single molecule consisting of a secreted domain fused to a transporter domain. The N-terminus of PlpD includes a classical signal peptide followed by the four PLP conserved blocks that account for its lipase activity. The C-terminus consists of a POTRA (polypeptide transport-associated) motif preceding a putative 16-stranded β-barrel similar to those of TpsB transporters of Type Vb secretion system. We showed that the C-terminus remains inserted into the outer membrane while the patatin moiety is secreted. The association between a TpsB component and a passenger protein is a unique hybrid organization that we propose to classify as Type Vd. More than 200 PlpD orthologues exist among pathogenic and environmental bacteria, which suggests that bacteria secrete numerous PLPs using this newly defined mechanism.

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