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

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 (MinENg) function was examined by generating amino acid substitutions of highly conserved MinENg residues and by testing the ability of the mutant proteins to interact with gonococcal MinD (MinDNg), to induce a minicell phenotype upon overexpression, to initiate MinDNg oscillation, and to stimulate MinDNg ATPase activity. N-terminal MinENg mutants were unable to bind to MinDNg; thus, they did not induce a minicell phenotype, promote MinDNg oscillation or stimulate MinDNg ATPase activity. While C-terminal MinENg mutants exhibited reduced abilities to bind to MinDNg, we show that differences in MinDNg binding to the C-terminus of MinENg alter the ability of MinENg to properly stimulate MinDNg activity. We present four major findings from our studies of MinENg: both the N- and C-termini of MinENg interact with MinDNg; interaction between MinDNg and MinENg is required for the recruitment of MinDNg to the coiled array; oscillation of MinDNg does not require ATPase stimulation; and, the extent of MinDNg ATPase stimulation depends on the binding strength between MinDNg and the C-terminus of MinENg.