Microfluidic trapping of vesicles reveals membrane-tension dependent FtsZ cytoskeletal re-organisation

Abstract

The geometry of reaction compartments can affect the outcome of chemical reactions.Synthetic biology commonly uses giant unilamellar vesicles (GUVs) to generate cell-sized, membrane-bound reaction compartments. However, these liposomes are always spherical due to surface area minimization. Here, we have developed a microfluidic chip to trap and reversibly deform GUVs into rod-or cigar-like shapes, including a constriction site in the trap mimicking the membrane furrow in cell division. When we introduce into these GUVs the bacterial tubulin homologue FtsZ, the primary protein of the bacterial Z ring, we find that FtsZ organization changes from dynamic rings to elongated filaments upon GUV deformation, and that these FtsZ filaments align preferentially with the short GUV axis, in particular at the membrane neck. In contrast, pulsing Min oscillations in GUVs remained largely unaffected.We conclude that microfluidic traps are a useful tool for deforming GUVs into non-spherical membrane shapes, akin to those seen in cell division, and for investigating the effect of confinement geometry on biochemical reactions, such as protein filament self-organization.

Curved membrane structures induced by native lipids in giant vesicles

“…Giant unilamellar vesicles (GUV's) have been the model of choice to control and mimic such cellular membrane shapes for bottom-up biology applications, including understanding the localization properties of proteins [6]. Previous studies on curvature-protein-induced deformation in synthetic cells have been predominantly reported in lipid mixtures that remotely mimic cellular membranes [7][8][9]. Local spontaneous curvature is also generated by an asymmetry of ions and macromolecules apart from proteins across membranes, inducing shape changes, which have been described mainly in simple lipid vesicles [10][11][12][13].…”

Production of giant unilamellar vesicles and encapsulation of lyotropic nematic liquid crystals

“…[1][2][3][4][5][6][7][8] They are widely used as cell models (protocells) 9,10 and in studies in which the ultimate aim is to create artificial life. [10][11][12][13][14][15] As a result, many methods have been developed for their production and for encapsulating materials within them. [16][17][18][19][20][21] None of these methods are wholly problem-free 22 but microfluidic approaches probably offer most control.…”