FtsZ in Bacterial Cytokinesis: Cytoskeleton and Force Generator All in One

Department of Cell Biology, Box 3709, Duke University Medical Center, Durham, NC 27710, USA.
Microbiology and molecular biology reviews: MMBR (Impact Factor: 14.61). 12/2010; 74(4):504-28. DOI: 10.1128/MMBR.00021-10
Source: PubMed


FtsZ, a bacterial homolog of tubulin, is well established as forming the cytoskeletal framework for the cytokinetic ring. Recent work has shown that purified FtsZ, in the absence of any other division proteins, can assemble Z rings when incorporated inside tubular liposomes. Moreover, these artificial Z rings can generate a constriction force, demonstrating that FtsZ is its own force generator. Here we review light microscope observations of how Z rings assemble in bacteria. Assembly begins with long-pitch helices that condense into the Z ring. Once formed, the Z ring can transition to short-pitch helices that are suggestive of its structure. FtsZ assembles in vitro into short protofilaments that are ∼30 subunits long. We present models for how these protofilaments might be further assembled into the Z ring. We discuss recent experiments on assembly dynamics of FtsZ in vitro, with particular attention to how two regulatory proteins, SulA and MinC, inhibit assembly. Recent efforts to develop antibacterial drugs that target FtsZ are reviewed. Finally, we discuss evidence of how FtsZ generates a constriction force: by protofilament bending into a curved conformation.

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    • "Electron microscopy was performed as described[1,2,49]. FtsZ was assembled with GTP as for light scattering in the standard buffer (50 mM MES, pH 6.5, 50 mM KCl, 2.5 mM MgCl 2 , 1 mM EGTA) or a buffer that instead had 250 mM KCl. 5 μM FtsZ was used for all in vitro assembly experiments. "
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