The Legionella pneumophila F-box protein Lpp2082 (AnkB) modulates ubiquitination of the host protein parvin B and promotes intracellular replication

Authors

  • M. Lomma,

    1. Institut Pasteur, Biologie des Bactéries Intracellulaires, Departement Genomes et Génétique, F-75015 Paris, France.
    2. CNRS, URA 2171, F-75015 Paris, France.
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  • D. Dervins-Ravault,

    1. Institut Pasteur, Biologie des Bactéries Intracellulaires, Departement Genomes et Génétique, F-75015 Paris, France.
    2. CNRS, URA 2171, F-75015 Paris, France.
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  • M. Rolando,

    1. Institut Pasteur, Biologie des Bactéries Intracellulaires, Departement Genomes et Génétique, F-75015 Paris, France.
    2. CNRS, URA 2171, F-75015 Paris, France.
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  • T. Nora,

    1. Institut Pasteur, Biologie des Bactéries Intracellulaires, Departement Genomes et Génétique, F-75015 Paris, France.
    2. CNRS, URA 2171, F-75015 Paris, France.
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  • H. J. Newton,

    1. Department of Microbiology and Immunology, University of Melbourne, Victoria 3010, Australia.
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  • F. M. Sansom,

    1. Department of Microbiology and Immunology, University of Melbourne, Victoria 3010, Australia.
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  • T. Sahr,

    1. Institut Pasteur, Biologie des Bactéries Intracellulaires, Departement Genomes et Génétique, F-75015 Paris, France.
    2. CNRS, URA 2171, F-75015 Paris, France.
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  • L. Gomez-Valero,

    1. Institut Pasteur, Biologie des Bactéries Intracellulaires, Departement Genomes et Génétique, F-75015 Paris, France.
    2. CNRS, URA 2171, F-75015 Paris, France.
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  • M. Jules,

    1. Institut Pasteur, Biologie des Bactéries Intracellulaires, Departement Genomes et Génétique, F-75015 Paris, France.
    2. CNRS, URA 2171, F-75015 Paris, France.
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    • Present address: Institut Micalis, Microbiologie de l'Alimentation au service de la Santé, INRA (UMR1319) et AgroParisTech, CBAI, Avenue Lucien Brétignières, 78850 Thiverval-Grignon, France.

  • E. L. Hartland,

    1. Department of Microbiology and Immunology, University of Melbourne, Victoria 3010, Australia.
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  • C. Buchrieser

    Corresponding author
    1. Institut Pasteur, Biologie des Bactéries Intracellulaires, Departement Genomes et Génétique, F-75015 Paris, France.
    2. CNRS, URA 2171, F-75015 Paris, France.
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E-mail carmen.buchrieser@pasteur.fr; Tel. (+33) 1 45 68 83 72; Fax (+33) 1 45 68 87 86.

Summary

The environmental pathogen Legionella pneumophila encodes three proteins containing F-box domains and additional protein–protein interaction domains, reminiscent of eukaryotic SCF ubiquitin–protein ligases. Here we show that the F-box proteins of L. pneumophila strain Paris are Dot/Icm effectors involved in the accumulation of ubiquitinated proteins associated with the Legionella-containing vacuole. Single, double and triple mutants of the F-box protein encoding genes were impaired in infection of Acanthamoeba castellanii, THP-1 macrophages and human lung epithelial cells. Lpp2082/AnkB was essential for infection of the lungs of A/J mice in vivo, and bound Skp1, the interaction partner of the SCF complex in mammalian cells, similar to AnkB from strain AA100/130b. Using a yeast two-hybrid screen and co-immunoprecipitation analysis we identified ParvB a protein present in focal adhesions and in lamellipodia, as a target. Immunofluorescence analysis confirmed that ectopically expressed Lpp2082/AnkB colocalized with ParvB at the periphery of lamellipodia. Unexpectedly, ubiquitination tests revealed that Lpp2082/AnkB diminishes endogenous ubiquitination of ParvB. Based on these results we propose that L. pneumophila modulates ubiquitination of ParvB by competing with eukaryotic E3 ligases for the specific protein–protein interaction site of ParvB, thereby revealing a new mechanism by which L. pneumophila may employ translocated effector proteins to promote bacterial survival.

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