Actin-microtubule co-formation inside of a giant unilamellar vesicle.

Microtubule and actin cytoskeletons are physically contacted in a cell, and dynamically coordinated to play vital roles in many cell functions, from migration, growth, and division. These structural dynamics of cytoskeletal proteins are of interest, the physical roles of cross-linking proteins between two filaments have been identified. Yet most studies were performed in a highly controlled interface or a bulk. Recently, we developed to simulate a cytoskeleton formation through ATP-dependent actin polymerization in a giant unilamellar vesicle. Optical stimulation initiated ATP synthesis and induced ATP-dependent actin polymerization, leading to growth of three-dimensional highly curled actin filament network. In this study, we further added the ingredients for microtubule formation into the actin polymerizable GUV system, and initiated the filament formations of those two cytoskeleton proteins simultaneously. We will discuss how these highly curled actin filaments in the single vesicle affects the structural environment in the presence of highly straight microtubule filaments. We will discuss how these two filaments are interacting in a highly confined, cell-like space where they are mutually restricted.