Figure 3.

ExoU mediated activation of host cell signalling pathways. 1. The injected active ExoU stimulates the mitogen-activated protein kinase (MAPK) signalling cascade through an unknown mechanism. MEKs phosphorylate c-Jun NH2 terminal kinase (JNKs), which translocate to the nucleus and activate c-Fos and c-Jun transcription factors to stimulate the inflammatory response. 2. Active ExoU cleaves membrane phospholipids at the sn2 position to yield arachidonic acid. Arachidonic acid is converted to prostaglandins PGE₂ and PGI₂ by cyclooxygenases Cox-1 and Cox-2 and endoperoxides PGG₂ and PGH₂.