SER/THR PHOSPHORYLATION OF FLAGELLAR MOTILITY PROTEIN, FLIC AND ITS BIOLOGICAL EFFECTS IN PSEUDOMONAS AERUGINOSA PAO1

Abstract

The focus of this study is on the biological effects of two potential serine/threonine phosphosites identified in the flagellar motility protein flagellin of Pseudomonas aeruginosa PAO1 .We report here that ser/thr mutation of FliC does not affect motility or chemotaxis but with significant affects on at three surface-associated phenomena -- biofilm formation, extracellular virulence factor secretion through Type 2 Secretion System (T2SS) and alginate secretion system. Flagellin phosphorylation affects the secretion system at a post-translational level. Flagellin phosphorylation also affected biofilm architecture, initial attachment and dispersal based on static and flow cell studies. Alginate secretion via a separate secretion system and related to the formation of biofilm matrix was also significantly affected. This study provides a link between ser/thr/tyr phosphorylation and virulence factor secretion and can improve our understanding of coordinated control of virulence mechanisms using Pseudomonas as a model bacterial pathogen.