FimV, ParC and ParP coordinate polar assembly of the chemosensory arrays in Pseudomonas putida

Motile bacteria rely on chemotaxis to promote directional motion in response to specific environmental signals. The bacterial chemotaxis machinery is typically arranged in highly ordered arrays containing multiple chemoreceptors and signal transduction proteins. Pseudomonas putida is a polarly flagellated soil bacterium displaying chemotaxis towards numerous organic compounds. Here we demonstrate the involvement of the polar landmark proteins FimV, ParC and ParP in the assembly of the flagella-associated chemosensory arrays at the cell poles in P. putida. Our results show that FimV, ParC and ParP are sequentially recruited to the new cell pole during the cell cycle. FimV is located at the new cell pole concurrently with cell division, and is further required for ParC recruitment. FimV and ParC subsequently stimulate polar localization of ParP. Bacterial two-hybrid assays and structural modeling suggest the involvement of direct protein-protein interactions between the three proteins. We also show that ParC and ParP are decisive to the assembly of fully formed polar chemosensory arrays, by recruiting chemosensory proteins to the cell pole, promoting the stable association of the histidine kinase CheA with the cell pole and enabling the assembly of the functional array structure. Polar targeting of both flagella and chemosensory arrays to the new pole in the timespan of a cell cycle is a means to secure correct segregation of the motility apparatus to both daughter cells during cell division. HIGHLIGHTSO_LIFimV, ParC and ParP promote chemosensory array assembly at the new cell pole C_LIO_LIFimV is essential to the normal intracellular distribution of ParC and ParP C_LIO_LIParC and ParP recruit and stabilize the array components at the cell poles C_LIO_LIParP and CheA promote polar clustering of the chemoreceptors C_LIO_LIAssembly in the timespan of the cell cycle endows chemotaxis to both daughter cells C_LI GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=120 HEIGHT=200 SRC="FIGDIR/small/684771v3_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@143bbe3org.highwire.dtl.DTLVardef@1e46d26org.highwire.dtl.DTLVardef@1b9fea9org.highwire.dtl.DTLVardef@1fe3d6c_HPS_FORMAT_FIGEXP M_FIG C_FIG