Partitioning protein ParP directly links chemotaxis to biofilm dispersal in Pseudomonas aeruginosa

Abstract

11The recent characterization of partitioning proteins in the localization of chemotaxis 12 signal transduction systems was proposed to have broad implications for polarly-flagellated non-13 enterobacteriaceae gamma-proteobacteria. These studies showed that the loss of either 14 partitioning protein resulted in equivalent reductions in swimming motility and chemotaxis 15 protein localization and inheritance. However, the role of these chemotaxis partitioning proteins 16 outside of Vibrio spp. remains untested. Our studies on the chemotaxis partitioning proteins in 17 Pseudomonas aeruginosa revealed an unexpected role for the partitioning protein ParP. While 18 the P. aeruginosa ParC and ParP homologs are needed for wild type swimming motility, the loss 19 of ParP results in a greater swimming defect compared to the parC mutant. Our studies revealed 20 that the Par-like proteins directly interact with each other and the chemotaxis system, and ParP 21 interacts with DipA. Deletion of dipA results in a similar defect in swimming motility as the 22 parP mutant. ParP has an interdependence for polar cluster formation, but not localization, with 23 both CheA and DipA, and CheA cluster formation is partially dependent on ParP. Due to the 24 direct interactions and interdependence of cluster formation of ParP and DipA, and the similar 25 phenotypes of the parP and dipA mutants, further investigation into the role of ParP in biofilm 26 dispersion is warranted. 27 Importance 28 Impaired chemotaxis protein cluster formation or inheritance reduces chemotaxis which 29 can have an impact on of the virulence of a bacterium. In some gamma-proteobacteria there are 30 systems in place to ensure that chemotaxis proteins, like chromosomes and plasmids, are 31 localized for optimal chemotaxis and that daughter cells inherit their own clusters for use after 32 cell division. Par-like proteins have been implicated in the partitioning and localization of 33 3 chemotaxis proteins and the chemotactic ability of Vibrio spp. and Rhodobacter sphaeroides [1-34 3].We propose that Par-like proteins can do more than localize chemotaxis proteins to the poles 35 of the cells. In P. aeruginosa, they bring together other key proteins involved in regulating 36 flagellar-based motility, and we propose they function as a critical link between biofilm dispersal 37 and motility. 38 Introduction 39Spatial organization within bacterial cells results in the arrangement of proteins in distinct 40 subcellular locations. This organization is not always static, and in some instances, can change in 41 response to external cues or different stages within the bacterial lifecycle [4, 5]. There are a 42 significant number of cellular processes that are affected by spatial organization and polarity, 43 including signal transduction and motility. Bacterial chemotaxis is mediated by a two-component 44 chemosensory system wherein a motile bacterium senses chemo-effectors in its environment and 45 responds by moving towards favorable or away from unfavo...

Effects of Calcium and Signal Sensing Systems on Azorhizobium caulinodans Biofilm Formation and Host Colonization

“…The relationship between chemotaxis and biofilm formation has been reported in many bacteria (Reinhardt and Bardy, 2018), and numerous studies suggest that transcription of chemotactic genes are activated during biofilm initiation (Karatan and Watnick, 2009). A. caulinodans has one core chemotactic pathway, including CheA, CheW, CheY1, CheZ, CheB, and CheR, which is similar to Escherichia coli (Sourjik and Wingreen, 2012), and 43 chemoreceptors.…”