The C-terminus of MinE from Neisseria gonorrhoeae acts as a topological specificity factor by modulating MinD activity in bacterial cell division

Abstract MinE regulates the proper placement of the cytokinetic FtsZ ring at midcell by inducing the pole-to-pole movement of MinCD complexes. While the N-terminus of MinE has been implicated in MinD binding, a clear functional role of the C-terminus has not been elucidated. We previously determined that MinE from Neisseria gonorrhoeae (Ng) was functional in Escherichia coli (Ec). Thus, using E. coli as a model organism, gonococcal MinE (MinE Ng ) function was examined by generating amino acid substitutions of highly conserved MinE Ng residues and by testing the ability of the mutant proteins to interact with gonococcal MinD (MinD Ng ), to induce a minicell phenotype upon overexpression, to initiate MinD Ng oscillation, and to stimulate MinD Ng ATPase activity. N-terminal MinE Ng mutants were unable to bind to MinD Ng ; thus, they did not induce a minicell phenotype, promote MinD Ng oscillation or stimulate MinD Ng ATPase activity. While C-terminal MinE Ng mutants exhibited reduced abilities to bind to MinD Ng , we show that differences in MinD Ng binding to the C-terminus of MinE Ng alter the ability of MinE Ng to properly stimulate MinD Ng activity. We present four major findings from our studies of MinE Ng : both the N- and C-termini of MinE Ng interact with MinD Ng ; interaction between MinD Ng and MinE Ng is required for the recruitment of MinD Ng to the coiled array; oscillation of MinD Ng does not require ATPase stimulation; and, the extent of MinD Ng ATPase stimulation depends on the binding strength between MinD Ng and the C-terminus of MinE Ng.