DNA transport within confined motor-driven cytoskeletal networks

Transport of macromolecules through the cytoskeleton is dictated by an interplay between steric obstacles and viscoelasticity from filamentous protein networks, advection and restructuring of the cytoskeleton via motor proteins, and confinement by the cell membrane. In vitro reconstitution of cytoskeletal networks have facilitated studies on how transport dynamics depend on each of these factors independently. Previously, we showed how macromolecular crowding and confinement synergistically couple to dramatically slow the diffusion of crowded DNA molecules that are confined by lipid membranes to cell-sized volumes. Here, we build on this work by incorporating motor-driven cytoskeletal composites into this platform. Specifically, we use differential dynamic microscopy and single-particle tracking to measure the active and thermal transport of particles in motor-driven composites of actin and microtubules confined in cell-sized droplets. We elucidate how anomalous subdiffusion due to caging and steric interactions competes with superdiffusive advection due to motor activity and how the dynamics depend on motor concentration and confinement size.