Unravelling the response of the actin cortex to electric pulses in vesicles

The plasma membrane is essential for maintaining the integrity of living cells. Its shape and mechanical properties are regulated by a subjacently attached interconnected network of actin filaments, known as the "actin cortex". The actin cortex is a major factor influencing the mechanical response of the cell to external physical cues. In this study, using giant unilamellar vesicles (GUVs) as a model system, we investigate the role of the actin cortex during the application of electric pulses that induce electroporation or electropermeabilization. We demonstrate that the presence of an actin cortex inhibits the formation of macropores in the electroporated GUVs and slows down the resealing process of the permeabilized membrane. We further analyze the stability of the actin cortex inside the GUVs exposed to high electric pulses. We find disruption of the actin cortex that is likely due to the electrophoretic forces acting on the actin filaments during the permeabilization of the GUVs. Our findings also reveal that the current simplified experimental models of cells need to be endowed with an actin cortex in order to more closely mimic the complex nature of cellular membranes.