Real-world modeling of artificial motile cell

Using a spontaneous transfer method, cell-sized giant liposomes encapsulating desired amounts of actoHMM, a mixture of actin filament (F-actin) and heavy meromyosin (HMM, an actin-related molecular motor), have been successfully constructed in the presence of 5 mM MgCl₂ and 50 mM KCl. The encapsulated actoHMM formed self-organized actin network-like structures, and non-spherical liposomes were obtained in a reproducible manner. In order to power the system with actoHMM in an effective manner, we have tried to supply ATP through protein pores embedded in the closed bilayer membrane. By the ATP supply, the network structures of F-actin formed inside the liposomes showed redistributions, which are attributable to the sliding between F-actin and HMM. This study serves as the first step in developing motile giant liposomes containing actoHMM, and in generating spontaneous motion in a system similar manner as in living cells.