Sylvia Simon, Maria A. Wagner, Eva Rothmeier, Annette Müller-Taubenberger and Hubert Hilbi
The amoebae-resistant opportunistic pathogen Legionella pneumophila determines host cell interactions through the Icm/Dot type IV secretion system, which translocates ∼ 300 different “effector” proteins into cells. L. pneumophila was found to inhibit chemotactic and random migration of Dictyostelium amoebae, macrophages and neutrophils in an Icm/Dot-dependent manner. L. pneumophila lacking the Icm/Dot-translocated Ran GTPase activator LegG1 hyper-inhibited phagocyte migration, and reliant on Ran, LegG1 promoted cell migration. Thus, LegG1-dependent Ran activation and consequent microtubule polymerization antagonize Icm/Dot-dependent inhibition of cell migration.