Repetitive stretching of giant liposomes utilizing the nematic alignment of confined actin

Abstract

Giant liposomes encapsulating cytoskeletons have been constructed to further understand the mechanisms of cell movement and develop cell-sized chemical machineries. Innovative studies demonstrating liposomal movements using microtubules and the molecular motors kinesin/dynein have been reported. However, no one has succeeded in generating repetitive motions controlled by external stimuli. Here we show that if the actin concentration in liposomes is comparable to that of cytoplasm of living cells, the liposomes can be deformed into spindle shapes by encapsulating only actin filaments, even without the molecular motor myosin. Furthermore, their shapes can be changed reversibly between spindle and sphere shapes by adjusting osmotic pressure or by light irradiation of fluorescent-labeled actin. In the latter case, the repetitive shape changes are accompanied with stretching and shrinking of filopodia-or acrosome projection-like extensions. Our results indicate that filamentous polymer of variable length like actin filament is a potential material for the reproduction of cell-like movement.

Cell mimicry as a bottom‐up strategy for hierarchical engineering ofnature‐inspiredentities

“…Further, membrane expansion was achieved using a cascading biosynthesis pathway containing eight membrane proteins (Exterkate, Caforio, Stuart, & Driessen, 2018) and the self‐reproduction of boundary membrane layers was recently reviewed elsewhere (Exterkate & Driessen, 2019). The cytoskeleton has received attention to create dynamic ACs with actin polymerization inside GUVs (Lee et al, 2018), artificial cilia using microtubule/kinesin (Sasaki et al, 2018), or nematic alignment of actin to study cell movement through repetitive motion upon external stimuli (Tanaka, Takiguchi, & Hayashi, 2018). Controlled deformation of GUVs was developed using 3D‐printed protein hydrogel scaffolds to dynamically achieve spatial anisotropy under pH stimuli (Jia et al, 2020).…”

Recent Advances in Liposome-Based Molecular Robots

“…The Hotani group reported morphological changes of G-actin encapsulated GUVs by increasing the temperature, with the shapes of GUVs being dependent on the type of actin-crosslinking proteins due to the organization of their specific actin networks [ 109 , 110 ]. The Hayashi group also reported the transformation of GUVs induced by the encapsulated actin ( Figure 7 a) [ 111 , 112 ]. They successfully deformed the GUV by increasing the concentration of the encapsulated actin to a level comparable to that of the cytoplasm of living cells.…”

“…( a ) Reversible deformations of GUVs between spindle and sphere shapes by light irradiation of fluorescent-labeled actin. Reproduced with permission from [ 112 ]. ( b ) Controllable and programmable deformation of GUVs.…”

Lessons from a Minimal Genome: What Are the Essential Organizing Principles of a Cell Built from Scratch?

“…[83] This experiment was performed in droplets, but it would be interesting to observe this process within al iposome. [85] The spatiotemporal control of actin polymerization is extremely complex, and although these advances are fascinating, using actin filaments or microtubules for the controlled and faithful divisiono faSynCell will be difficult. [85] The spatiotemporal control of actin polymerization is extremely complex, and although these advances are fascinating, using actin filaments or microtubules for the controlled and faithful divisiono faSynCell will be difficult.…”