Stepwise remodelling and subcompartment formation in individual vesicles by three ESCRT-III proteins
The endosomal sorting complex required for transport (ESCRT) is a multi-protein complex involved in several membrane remodelling processes. Different approaches have been used to dissect the mechanism by which ESCRT proteins produce scission in the membranes. However, the underlying mechanisms generating the membrane deformations remain poorly understood. In this study, giant unilamellar vesicles (GUVs), microfluidic technology and micropipette aspiration are combined to continuously follow the ESCRT-III-mediated membrane remodelling on the single-vesicle level for the first time. With this approach, we identify different mechanisms by which a minimal set of three ESCRT-III proteins from the phagocytic parasite Entamoeba histolytica reshape the membrane. These proteins modulate the membrane stiffness and spontaneous curvature to regulate the bud size and generate intraluminal vesicles in GUVs even in the absence of ATP. We show that the bud stability depends on the protein concentration and membrane tension. The approach introduced here should open the road to diverse applications in synthetic biology for establishing artificial cells with several membrane compartments.