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Updated: Feb 18, 2026

Legionella pneumophila Outer Membrane Vesicles: Isolation and Analysis of Their Pro-inflammatory Potential on Macrophages
Published on: February 22, 2017
Structural insights into Legionella RidL-Vps29 retromer subunit interaction reveal displacement of the regulator
Kevin Bärlocher1, Cedric A J Hutter1, A Leoni Swart1
1Institute of Medical Microbiology, University of Zürich, Gloriastrasse 30, 8006, Zürich, Switzerland.
Abstract:
Legionella pneumophila can cause Legionnaires' disease and replicates intracellularly in a distinct Legionella-containing vacuole (LCV). LCV formation is a complex process that involves a plethora of type IV-secreted effector proteins. The effector RidL binds the Vps29 retromer subunit, blocks retrograde vesicle trafficking, and promotes intracellular bacterial replication. Here, we reveal that the 29-kDa N-terminal domain of RidL (RidL2-281) adopts a "foot-like" fold comprising a protruding β-hairpin at its "heel". The deletion of the β-hairpin, the exchange to Glu of Ile170 in the β-hairpin, or Leu152 in Vps29 abolishes the interaction in eukaryotic cells and in vitro. RidL2-281 or RidL displace the Rab7 GTPase-activating protein (GAP) TBC1D5 from the retromer and LCVs, respectively, and TBC1D5 promotes the intracellular growth of L. pneumophila. Thus, the hydrophobic β-hairpin of RidL is critical for binding of the L. pneumophila effector to the Vps29 retromer subunit and displacement of the regulator TBC1D5.
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