A Microfluidic Approach To The Study Of Z-Ring Dynamics Formation In Liposomes

Thanks to recent improvements in biological engineering, the idea of building a synthetic minimal cell that is able to replicate itself using a minimal amount of components has recently emerged as an ambitious goal that may be feasible to achieve in the long term. Following a bottom-up approach, two essential elements are required to provide the fundamental functionality of cellular division: a lipid membrane for confinement and a protein machinery to carry out fission. We have developed a technique to produce cell-size liposomes by means of a microfluidic device, which provides an innovative way to obtain monodisperse membrane confinements with a fine control over the concentrations of the solutions inside and outside the membrane (see the contribution by S. Deshpande in this conference). To these liposomes, we administer a minimal form of the divisome machinery of E. coli, viz., the proteins that constitute the Z-ring, a highly dynamic structure responsible for the membraneu0027s constriction and fission. A central element of the Z-ring is FtsZ, a protein that, under GTP hydrolysis, polymerizes into filament structures that have been suggested to provide the force to constrict the membrane. Using our microfluidics and fluorescence microscopy, we temporally resolve the FtsZ filaments formation and their interaction with the membrane anchor proteins FtsA and ZipA, studying the entity of the liposome deformation to optimize the crowding conditions required for the divisome machinery to better perform its constrictive action on the membrane.