Comparative proteomic analysis of exoproteome and membrane enriched fractions of PAK and PAK pJN2133 strains

This work characterizes a P.aeruginosa strain with low levels of c-di-GMP resultant from the overexpression of the phosphodiesterase PA2133. Phenotypic characterization showed that biofilm formation, adhesion to epitheliel cells, and motility are severely impaired in this strain. We applied both, DIGE / MALDI-TOF/TOF and shotgun LC/MS/MS quantitative proteomic analysis to exoproteome and enriched membrane protein fractions. Results from both complementary strategies were in agreement and revealed motility, type III secretion, and chemotaxis to be the main affected processes by PA2133 overexpression. These results are the first to show that flagella synthesis, twitching motility, and chemotaxis are negatively regulated by low c-di-GMP levels in P.aeruginosa and thus confront our current undertsandings of c-di-GMP signalling.