FIG. 3.

The two ANK domains of AnkB are essential for acquisition of polyubiquitinated proteins by the LCV within macrophages. Representative confocal images of infected macrophages for colocalization of phagosomes with polyubiquitinated proteins at 2 h post-infection of U937 cells by the wild-type strain of L. pneumophila, the isogenic ankB mutant, or the ankB mutant harboring one of the mutant ankB alleles on a plasmid. The cells were labeled with anti-Lpn antibody (green) and antipolyubiquitin (red). The arrowheads indicate heavy colocalization of polyubiquitin with the bacterium. Quantification of colocalization of the LCVs with polyubiquitin at 2 h postinfection has been determined by analysis of 100 infected cells and is shown in the merged images. The data are representative of three independent experiments.