Medically Relevant Acinetobacter Species Require a Type II Secretion System and Specific Membrane-Associated Chaperones for the Export of Multiple Substrates and Full Virulence
Fig 6
The newly characterized LipH is secreted by the T2SS and displays lipase activity.
(A) Western blot analysis on whole cell lysates and secreted protein fractions probing for LipH-His. All strains and fractions were also analyzed for RNA polymerase expression, which served as a lysis control. LipH-His expression was detected in all strains carrying the pWH-lipH-his; however, LipH-His secretion was only detected in strains predicted to produce a functioning T2SS. (B) Western blot analysis on whole cell lysates and secreted protein fractions from a range of Acinetobacter clinical isolates heterologously expressing LipH-His from the pWH-lipH-his plasmid. LipH-His expression and secretion was detected in all clinical isolates tested. (C) Lipase activity of concentrated culture supernatants from the parent strain, the ∆lipH::kan mutant, and the lipH complemented strain. Increases in the A410 indicate lipase activity. A410 measurements were recorded every 30 minutes for 12 hours. Three biological replicates with three technical replicates were used for analysis.