FtsZ Reorganization Facilitates Deformation of Giant Vesicles in Microfluidic Traps**

Abstract

The geometry of reaction compartments can affect the local outcome of interface-restricted reactions. Giant unilamellar vesicles (GUVs) are commonly used to generate cell-sized, membrane-bound reaction compartments, which are, however, always spherical. Herein, we report the development of a microfluidic chip to trap and reversibly deform GUVs into cigar-like shapes. When trapping and elongating GUVs that contain the primary protein of the bacterial Z ring, FtsZ, we find that membrane-bound FtsZ filaments align preferentially with the short GUV axis. When GUVs are released from this confinement and membrane tension is relaxed, FtsZ reorganizes reversibly from filaments into dynamic rings that stabilize membrane protrusions; a process that allows reversible GUV deformation. We conclude that microfluidic traps are useful for manipulating both geometry and tension of GUVs, and for investigating how both affect the outcome of spatially-sensitive reactions inside them, such as that of protein self-organization.

DisGUVery: a versatile open-source software for high-throughput image analysis of Giant Unilamellar Vesicles

“…Having a detector that does not rely on vesicle shape is valuable, as shape control and GUV deformation are essential aspects of synthetic cell engineering. 9, 40, 73, 74 We demonstrate the use of FF on GUVs deformed by encapsulated stiff actin bundles (fig. 3C).…”

“…In this way, membrane deformation by fluores- cent structures can be quantified in an automated way for vesicle populations, enabling an accessible and quantitative approach in GUV deformation studies. Besides its use in actinmediated GUV deformation studies, 40,44,[77][78][79] this analysis is also valuable in other studies on global vesicle shape deformation, for example by other proteins involved in cytokinesis such as the bacterial division proteins FtsZ 80 and Min system, 73 by other membrane-binding proteins, 9 DNA origami, 81 by microfluidic traps, 74,82 or by spontaneous membrane fluctuations. 83 Furthermore, RMD could be applied to characterize local membrane deformations, such as protrusions 84 or nanotubes.…”

FtsZ Interactions and Biomolecular Condensates as Potential Targets for New Antibiotics

“…Deformation of the membrane was also achieved by de novo synthesis of FtsZ and ZipA in GUVs, but not with the FtsZ-mts chimera [ 115 ]. Finally, lipid vesicles produced by manual emulsion were deformed into rod-shaped containers by trapping them in microfluidic devices, allowing visualization studies of FtsZ-mts filament arrangement in bacterial cell-like geometries [ 142 ].…”

In vitro assembly, positioning and contraction of a division ring in minimal cells

“…For instance, due to the exceptionally low surface-tovolume ratio within microdroplets, spontaneous localization of MinE has to be modulated for a stable wave emergence 21,22 . In and on vesicles, FtsZ was able to deform membrane surfaces [23][24][25][26] and dynamically reorganize dependent on membrane shape and anchoring features 26,27 .…”

“…Despite the importance of the interactions between the Min proteins and FtsZ for proper FtsZ-ring placement, the co-reconstitution of these proteins, especially in con ned spaces, has rarely been accomplished so far [28][29][30][31] . This di culty is mainly due to a large number of components and environmental factors to be controlled and their intrinsic complex dynamics that are still not fully understood 27,32 .…”