To investigate whether LegU1 secreted by L. pneumophila during infection exerts the same activity on BiP as ectopically expressed LegU1 does, we analyzed the ubiquitination of endogenous BiP in Raw264.7 cells infected with the wild type (Lp02p) and ΔlegU1 (Lp02ΔU1p) strains of L. pneumophila. This evidence concerns the gene HSPA5 and infection.