FIGURE 1: Proposed model of LL-37 induced mutagenesis and mucoid conversion.

Step Ia, at low doses LL-37 (*) interacts with Pseudomonas aeruginosa and enters bacterial cells, binding to DNA (Step Ib). LL-37/DNA interactions promote mucA mutagenesis and conversion to the mucoid phenotype (Step II). Mucoid P. aeruginosa biofilms are now more resistant to killing by lethal levels of LL-37 and are selected for in the CF pulmonary environment (Step III).