Dependence of ATP content in the formation of protrusions in DMPC GUVs under an AC electric field

The cytoskeleton is an essential cell component. Many cellular processes that require changes in the cell structure depend on it. One of these processes is cell migration, which occurs through the formation of structures called protrusions that interact with other cytoskeletal components, enabling the cell to move slowly. These structures are formed by the polymerization of actin monomers, a process that requires the presence of ATP, as well as the exchange of divalent cations. In this work, we present a study on the formation of actin protrusions within DMPC giant unilamellar vesicles by varying the concentration of ATP, both in the absence and presence of MgCl₂. It was found that when the concentration of ATP in the overall protein buffer increases, these structures form and extend inside the vesicle without breaking it, even in the absence of MgCl₂. These protrusions are randomly oriented; however, when an alternating current electric field is applied, the protrusions align in the direction of the field in response to the polar nature of both lipids and actin filaments.