Roles of the bsc T3SS and the BteA effector in cytotoxicity. A. HeLa (blue bars), J774A.1 (red bars), or A549 cells (green bars) were infected with the indicated strains at a multiplicity of infection (MOI) of 50 in 24-well plates for 3 h. The bteA mutant strains were complemented in trans with the RB50 bteA allele carried on a medium copy vector (see Methods). Following infection, release of lactate dehydrogenase (LDH) into culture medium was measured as described in Methods. B. bteA homologues were compared using multialign  and amino acid differences are shown. Green lines indicate substitutions of highly conserved residues, blue shows weakly similar amino acids, red indicates no similarity, cyan dotted lines designate deletion of a residue and pink designates an amino acid insertion. Bp = B. pertussis, Bpp = B. parapertussis, LRT = lipid raft-targeting domain .