title: Listeria hijacks the clathrin-dependent endocytic machinery to invade mammalian cells.
abstract: The bacterial pathogen Listeria monocytogenes uses the surface protein InlB to invade a variety of cell types. The interaction of InlB with the hepatocyte growth-factor receptor, Met, is crucial for infection to occur. Remarkably, the ubiquitin ligase Cbl is rapidly recruited to InlB-activated Met. Recent studies have shown that ligand-dependent endocytosis of Met and other receptor tyrosine kinases is triggered by monoubiquitination of the receptor, a process that is mediated by Cbl. Here, we show that purified InlB induces the Cbl-dependent monoubiquitination and endocytosis of Met. We then demonstrate that the bacterium exploits the ubiquitin-dependent endocytosis machinery to invade mammalian cells. First, we show that L. monocytogenes colocalizes with Met, EEA1, Cbl, clathrin and dynamin during entry. Then, we assess the role of different proteins of the endocytic machinery during L. monocytogenes infection. Over-expression or down-regulation of Cbl, respectively, increases or decreases bacterial invasion. Furthermore, RNA interference-mediated knock-down of major components of the endocytic machinery (for example, clathrin, dynamin, eps15, Grb2, CIN85, CD2AP, cortactin and Hrs), inhibit bacterial entry, establishing that the endocytic machinery is key to the bacterial internalization process.
authors.affiliation: Unité des Interactions Bactéries-Cellules, Institut Pasteur; INSERM U604, INRA USC2020, 28 rue du Dr Roux, 75015 Paris, France.
authors.forename: Esteban
authors.initials: E
authors.lastname: Veiga
authors.forename: Pascale
authors.initials: P
authors.lastname: Cossart
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D002966:Clathrin / Q000378:metabolism*; D022163:Clathrin-Coated Vesicles / Q000378:metabolism*; D015536:Down-Regulation / Q000502:physiology; D034281:Dynamins / Q000378:metabolism; D004705:Endocytosis / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D008089:Listeria monocytogenes / Q000378:metabolism / Q000502:physiology*; D008088:Listeriosis / Q000235:genetics / Q000378:metabolism*; D008322:Mammals / Q000378:metabolism / Q000382:microbiology*; D008565:Membrane Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D050721:Proto-Oncogene Proteins c-cbl; D019859:Proto-Oncogene Proteins c-met / Q000378:metabolism; D034622:RNA Interference; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism; D033921:Vesicular Transport Proteins
chemical_list: D002352:Carrier Proteins; D002966:Clathrin; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D025801:Ubiquitin; D033921:Vesicular Transport Proteins; C093846:early endosome antigen 1; D050721:Proto-Oncogene Proteins c-cbl; D044767:Ubiquitin-Protein Ligases; D019859:Proto-Oncogene Proteins c-met; D034281:Dynamins; C067419:CBL protein, human