Pseudomonas aeruginosa Pili and Flagella Mediate Distinct Binding and Signaling Events at the Apical and Basolateral Surface of Airway Epithelium
Figure 8
Model for Tfp- or flagella-mediated P. aeruginosa binding and induction of signaling pathways and events at the AP or BL surface of polarized epithelium.
At the AP surface, P. aeruginosa binds to N-glycan chains through Tfp, which results in activation of PI3K and Akt. It remains to be investigated whether other signaling pathways can be activated upon Tfp binding to N-glycans. At the BL surface, (1) P. aeruginosa binds to HS chains of HSPGs through flagella and (2) the binding results in formation of the complex with EGFR and HB-EGF, which leads to activation of EGFR and subsequent activation of PI3K/Akt. Other signaling pathways can be possibly activated upon flagella binding to HS, dependently or independently of EGFR. Activation of PI3K/Akt at the AP surface, and EGFR and PI3K/Akt at the BL surface result in bacterial internalization and, most likely, in other pathogenic and host response events.