Biomimetic Liposome Model Systems to Study Cell Shape Control by the Cytoskeleton


Shape changes of animal cells during cell division, migration, and tissue morphogenesis depend on an interplay between the plasma membrane and the cytoskeleton. The actin and microtubule cytoskeleton provide mechanical support to the plasma membrane but also exert active forces to deform the membrane. The molecular complexity of cells makes it difficult to dissect the mechanochemical interplay of the cytoskeleton and the plasma membrane in cell shape control. An increasingly popular approach is to reconstitute biomimetic model systems that can mimic a certain cellular function with a minimal set of purified cellular constituents. Such in vitro studies have provided many quantitative insights into the physical and biochemical properties of purified cytoskeletal polymers and model biomembranes in isolation. However, until now, there has been relatively little work on more complex and physiologically relevant model systems combining model biomembranes with cytoskeletal proteins. Here, we review methods designed to build biomimetic model cells consisting of cell-sized (10–50 μm) liposomes encapsulating an actin or microtubule cytoskeleton. Moreover, we review recent results showcasing the reconstitution of increasingly complex model systems including physiological cytoskeleton–membrane linkers, nucleating factors, and molecular motors. Finally, we end with a short outlook providing ideas on future research directions.

Advances in Planar Lipid Bilayers and Liposomes