RT Journal Article SR Electronic T1 ZapA stabilizes FtsZ filament bundles without slowing down treadmilling dynamics JF bioRxiv FD Cold Spring Harbor Laboratory SP 580944 DO 10.1101/580944 A1 Caldas, Paulo A1 López-Pelegrín, Mar A1 Pearce, Daniel J.G. A1 Budanur, Nazmi B. A1 Brugués, Jan A1 Loose, Martin YR 2019 UL http://biorxiv.org/content/early/2019/03/19/580944.abstract AB For bacterial cell division, treadmilling filaments of FtsZ organize into a ring-like structure at the center of the cell. What governs the architecture and stability of this dynamic Z-ring is currently unknown, but FtsZ-associated proteins have been suggested to play an important role. Here, we used an in vitro reconstitution approach combined with fluorescence microscopy to study the influence of the well-conserved protein ZapA on the organization and dynamics of FtsZ filaments recruited to a supported membrane. We found that ZapA increases the spatial order and stabilizes the steady-state architecture of the FtsZ filament network in a highly cooperative manner. Despite its strong influence on their large-scale organization, ZapA binds only transiently to FtsZ filaments and has no effect on their treadmilling velocity. Together, our data explains how FtsZ-associated proteins can contribute to the precision and stability of the Z-ring without compromising treadmilling dynamics.