Engineered Composites of Actin Filaments, Microtubules, and Associated Motor Proteins

The cytoskeleton plays a key role in cellular force generation, shape change, and movement. Characterizing the physics of this dynamic structure is critical to understanding cell mechanobiology and functions. The interactions between the two main biopolymers that constitute the cytoskeleton, actin and microtubules, and the associated molecular motors myosin and kinesin are essential to cytoskeletal properties, but the mechanisms of their interactions are not easily understood. While actin systems and microtubule systems have been studies extensively, the material properties of their composites are less well-understood. We have developed a 3D bead-chain model of actin and microtubules without and with motors. We measure collective properties such as network acceleration, contraction speeds, and spatial correlations to provide insights into the emergent structure patterns and dynamics of this composite network. Our results may provide a broader understanding of the actin-microtubule interplay and how various motor proteins and crosslinkers impact the spatial organization and response to mechanical forces.