Endogenous membrane stress induces T6SS activity in Pseudomonas aeruginosa

The type 6 secretion system (T6SS is a dynamic organelle encoded by many gram-negative bacteria that can be used to kill competing bacterial prey species in densely occupied niches . Some predatory species, such as Vibrio cholerae, use their T6SS in an untargeted fashion while in contrast, Pseudomonas aeruginosa assembles and fires its T6SS apparatus only after detecting initial attacks by other bacterial prey cells ; this targeted attack strategy has been termed the T6SS tit-for-tat response. Molecules that interact with the P. aeruginosa outer membrane such as polymyxin B can also trigger assembly of T6SS organelles via a signal transduction pathway that involves protein phosphorylation . Recent work suggests that a phospholipase T6SS effector (TseL) of V. cholerae can induce T6SS dynamic activity in P. aer…