Bacterial cell cycle regulator MatP forms biomolecular condensates and directly interacts with cell division protein FtsZ

Abstract

ABSTRACTBacterial cytokinesis is driven by a contractile ring of FtsZ protein polymers at midcell. FtsZ can also form phase-separated biomolecular condensates with potential implications for cytokinesis and development of antibiotic-tolerant persister cells. InEscherichia coli, FtsZ ring positioning depends in part on the MatP protein, which binds DNA sites (matS) in the chromosome terminus region and indirectly interacts with FtsZ through two other proteins. We report here that MatP also forms biomolecular condensates in reconstituted systems that mimic the crowded bacterial cytoplasm, on its own or with FtsZ. Our biophysical analyses uncover a direct MatP-FtsZ interaction, which is disrupted bymatSsites that also regulate MatP condensate formation. These condensates preferentially locate at the surface of lipid droplets, a behavior probably mediated by MatP-lipid binding. GTP triggers assembly of FtsZ polymers from FtsZ-MatP condensates. These polymers are decorated with MatP, but exposure tomatSsites releases MatP. SuchmatS-responsive MatP biomolecular condensates, regulated by GTP when coassembled with FtsZ, may provide a mechanism for MatP storage and rapid mobilization that could facilitate MatP’s role in spatially regulating cytokinesis. Moreover, sequestration of MatP through phase separation could promote cell entry into dormant states that are able to survive antibiotic treatments.GRAPHICAL ABSTRACT