Min waves without MinC can pattern FtsA-FtsZ filaments on model membranes

Abstract

Although the essential proteins that drive bacterial cytokinesis have been identified and reconstituted in vitro, the precise mechanisms by which they dynamically interact to enable symmetrical division are largely unknown. In Escherichia coli, cell division begins with the formation of a proto-ring composed of FtsZ and its membrane-tethering proteins FtsA and ZipA. In the broadly proposed molecular scenario for ring positioning, Min waves composed of MinD and MinE distribute the FtsZ-polymerization inhibitor MinC away from mid-cell, where the Z-ring can form. Therefore, MinC is believed to be an essential element connecting the Min and FtsZ systems. Here, by using cell-free gene expression on planar lipid membranes, we demonstrate that MinDE drive the formation of dynamic, antiphase patterns of FtsZ-FtsA co-filaments even in the absence of MinC. This behavior is also observed when the proteins are compartmentalized inside microdroplets. These results suggest that Z-ring positioning may be achieved with a more minimal set of proteins than previously envisaged, providing a fresh perspective about the role of MinC. Moreover, we propose that MinDE oscillations may constitute the minimal localization mechanism of an FtsA-FtsZ constricting ring in a prospective synthetic cell.