Contact
    Start Publications In vitro reconstitution of Escherichia coli divisome activation
    ←  Publication Finder
    QSense

    In vitro reconstitution of Escherichia coli divisome activation

    Journal: Nat. Commun., Volume 13, MAY 12

    Authors: Radler, Philipp; Baranova, Natalia; Caldas, Paulo; Sommer, Christoph; Lopez-Pelegrin, Mar; Michalik, David; Loose, Martin

    Organizations: Scientific Service Units (SSU) of IST Austria; European Research Council [ERC 2015-StG-679239]; Austrian Science Fund (FWF) [StandAlone P34607, HFSP LT 000824/2016-L4]

    The actin-homologue FtsA is essential for E. coli cell division, as it links FtsZ filaments in the Z-ring to transmembrane proteins. FtsA is thought to initiate cell constriction by switching from an inactive polymeric to an active monomeric conformation, which recruits downstream proteins and stabilizes the Z-ring. However, direct biochemical evidence for this mechanism is missing. Here, we use reconstitution experiments and quantitative fluorescence microscopy to study divisome activation in vitro. By comparing wild-type FtsA with FtsA R286W, we find that this hyperactive mutant outperforms FtsA WT in replicating FtsZ treadmilling dynamics, FtsZ filament stabilization and recruitment of FtsN. We could attribute these differences to a faster exchange and denser packing of FtsA R286W below FtsZ filaments. Using FRET microscopy, we also find that FtsN binding promotes FtsA self-interaction. We propose that in the active divisome FtsA and FtsN exist as a dynamic copolymer that follows treadmilling filaments of FtsZ. In E. coli, FtsA and FtsZ control the place and time of cell division. Here, the authors use in vitro experiments to show how FtsA can follow FtsZ treadmilling and that downstream proteins form dynamic copolymers with FtsA to initiate division.
    View publication