Liposome division by a simple bacterial division machinery

Abstract

We previously reconstituted Z rings in tubular multilamellar liposomes with FtsZ-YFP-mts, where mts is a membrane-targeting amphiphilic helix. These reconstituted Z rings generated a constriction force but did not divide the thick-walled liposomes. Here we developed a unique system to observe Z rings in unilamellar liposomes. FtsZ-YFP-mts incorporated inside large, unilamellar liposomes formed patches that produced concave distortions when viewed at the equator of the liposome. When viewed en face at the top of the liposome, many of the patches were seen to be small Z rings, which still maintained the concave depressions. We also succeeded in reconstituting the more natural, two-protein system, with FtsA and FtsZ-YFP (having the FtsA-binding peptide instead of the mts). Unilamellar liposomes incorporating FtsA and FtsZ-YFP showed a variety of distributions, including foci and linear arrays. A small fraction of liposomes had obvious Z rings. These Z rings could constrict the liposomes and in some cases appeared to complete the division, leaving a clear septum between the two daughter liposomes. Because complete liposome divisions were not seen with FtsZ-mts, FtsA may be critical for the final membrane scission event. We demonstrate that reconstituted cell division machinery apparently divides the liposome in vitro.acterial cytokinesis is generated by a complex ring-shaped structure comprising more than a dozen proteins. It is called a Z ring because the primary cytoskeletal framework is made by filamentous temperature-sensitive Z (FtsZ). FtsZ has a globular core homologous to tubulin, and at its C terminus there is an ∼50 amino acid unstructured peptide linker, followed by an ∼17 amino acid peptide that binds FtsA (see ref.

Defining the rate-limiting processes of bacterial cytokinesis

“…For example, purified, membrane-tethered FtsZ was shown to assemble into ring-like structures that deform and constrict liposome membranes (30)(31)(32)(33)(34)(35). Mechanistically, it has been proposed that a constrictive force could be generated by the bending of FtsZ protofilaments because of their preferred curvature or GTP hydrolysis-induced conformation change (36)(37)(38)(39)(40)(41), immediate reannealing of FtsZ protofilaments upon GTP hydrolysis-induced subunit loss (42), condensation of FtsZ protofilaments caused by their lateral affinity (43), or a combination of these mechanisms (38,42,44,45).…”

Monodisperse Uni- and Multicompartment Liposomes

“…9,10 Cell-sized liposomes that encapsulate biomolecules and incorporate biological functions provide a versatile mimic of certain aspects of living cells, as exemplified by work showing RNA replication, [11][12][13] in vitro transcription and translation of gene networks, 6,14-16 and organization of cell division machinery in liposomes. [17][18][19][20][21][22][23][24] …”

Divided we stand: splitting synthetic cells for their proliferation

“…When FtsZ-YFP was incubated inside synthetic liposomes together with FtsA H , GTP and ATP, a progressive formation of an interluman septum was observed in a small fraction of the vesicles (1.3 %) (see Fig. 5b) (Osawa and Erickson 2013). It was suggested that in these group of vesicles, the activity of the anchored FtsZ protofilaments was the driving force for the septum formation.…”