(A) L. pneumophila subpopulation proteomics. A. castellanii was infected (MOI 5, 42 h) with L. pneumophila JR32 (Ptac-mCherry-PflaA-gfp). After cell lysis, released intracellular bacteria were sorted by flow cytometry in mCherry-positive/GFP-negative and mCherry-positive/GFP-positive L. pneumophila subpopulations, and their proteome was determined and compared. Protein abundance in each subset is depicted as a volcano plot. Proteins enriched in the GFP-producing subpopulation have a positive log2 ratio (q-value). 