Species- and C-terminal linker-dependent variations in the dynamic behavior of FtsZ on membranesin vitro

Abstract

Summary: 1 4Bacterial cell division requires the assembly of FtsZ protofilaments into a dynamic structure 1 5 called the 'Z-ring'. The Z-ring recruits the division machinery and directs local cell wall 1 6 remodeling for constriction. The organization and dynamics of protofilaments within the Z-ring 1 7 coordinate local cell wall synthesis during cell constriction, but their regulation is largely 1 8unknown. The disordered C-terminal linker (CTL) region of Caulobacter crescentus FtsZ 1 9 (CcFtsZ) regulates polymer structure and turnover in solution in vitro, and regulates Z-ring 2 0 structure and activity of cell wall enzymes in vivo. To investigate the contributions of the CTL to 2 1 the polymerization properties of FtsZ on its physiological platform, the cell membrane, we 2 2 reconstituted CcFtsZ polymerization on supported lipid bilayers (SLB) and visualized polymer 2 3 dynamics and structure using total internal reflection fluorescence microscopy. Unlike E. coli 2 4FtsZ protofilaments that organized into large, bundled patterns, CcFtsZ protofilaments 2 5 assembled into small, dynamic clusters on SLBs. Moreover, CcFtsZ lacking its CTL formed 2 6 large networks of straight filament bundles that underwent slower turnover than the dynamic 2 7clusters of wildtype FtsZ. Our in vitro characterization provides novel insights into species-and 2 8 CTL-dependent differences between FtsZ assembly properties that are relevant to Z-ring 2 9 assembly and function on membranes in vivo.

The speed of FtsZ treadmilling is tightly regulated by membrane binding

“…5-ii) will ensure the correct formation of FtsZ rings, not only keeping the right distance between the membrane and FtsZ filaments, but also between the filaments themselves 6 . Given that this particular domain properties are organism specific, further studies as performed by Sundararajan et al 2017Sundararajan et al , 2018 will be required for a comprehensive picture. Our results indicate that elimination of the CTL increases lateral interactions that affect treadmilling.…”

Synthetic developmental regulator MciZ targets FtsZ across Bacillus species and inhibits bacterial division

“…The Z‐ring has a fast subunit turnover (Anderson et al , ) and is composed of discrete FtsZ clusters that circumferentially treadmill guiding septal cell wall synthesis (Bisson‐Filho et al , ; Yang et al , ; Monteiro et al , ), leading to the scission of daughter cells. FtsZ is a tubulin‐like GTPase whose subunits assemble head‐to‐tail forming polar filaments (Nogales et al , ; Matsui et al , ) that laterally associate into bundles through the disordered C‐terminal tails (Buske et al , ; Huecas et al , ; Sundararajan et al , ). GTP hydrolysis at the interface between monomers in filaments and a polymerization‐driven structural switch enable FtsZ filament treadmilling dynamics (Artola et al , ; Wagstaff et al , ).…”