Reconstitution of the artificial amoeboid system based on bacterial membrane protein ActA mediated actin motility

Actin is a well-known cytoskeleton protein performing morphology and locomotion of the cell. Listeria monocytogenes, pathogenic bacteria, can move intracellular space using the actin motility system of their host cells. Their transmembrane protein, ActA, can recruit actin polymerization factors of the cell, such as Arp2/3 complex and VASP proteins. Particularly, the ActA proteins localized on the pole surface of the bacteria concentrate actin polymerization on the end point of their bacterial bodies and propel their movement in the direction of both sides creating actin comet tails. Previously, research studies have investigated micro-bead motility test based on the ActA interfacial mechanism in cytoplasm extracts, and artificial motility media that included several actin binding proteins (ABPs), ATP, and ions. We had not only observed actin comet tails with ActA conjugated micro-beads in the minimum essential motility solution but also confirmed that the ActA mediated actin polymerization generated sufficient force for the vesicle protrusion. Here we enclosed the ActA conjugated gold nano-particles with actin motility solution including non-muscle actin, ABPs, ATP, ATP regenerating enzymes, and cations into the liposome. Consequently, we can observe liposome vesicle movement protruding their pseudopodia. (Moreover, the vesicle motility was faster than the ActA-conjugated micro-bead motility in the minimum essential motility solution. In the proposed approach, this nano-bio fused artificial amoeboid-like system is to be a novel biomimetic species in prospective applications of biopowered devices.