During the active transport of cellular cargo along cytoskeletal tracks, forces generated by molecular motors both propel the cargo and affect the underlying organization of cytoskeletal filaments. In our research, we used coarse-grained simulations of actin filaments and cargo-bound molecular motors to study the feedback between active cargo transport and filament organization.

In the cover image of the February 18 issue of Biophysical Journal, we compared the spatial distribution of cargoes in a confined domain for different numbers of motors per cargo (increasing from left to right and top to bottom). Each panel shows the spatial distribution of cargoes averaged over multiple trajectories, which we analyzed by using custom MATLAB scripts. In each case, a bright, high-occupancy region emerges at the center, with darker, low-occupancy regions closer to the periphery. This indicates the spontaneous emergence of cargo-rich domains near the center. Additional analysis shows that these regions are surrounded by filament-rich domains comprised of filaments that are locally sorted according to their polarity. Taken together, our work demonstrates spontaneous organization arising from the feedback between motor-driven cargo transport and cytoskeletal filament organization.

This research can be applied to understand motor-filament interactions in other contexts. For example, applications range from actin reorganization during fertilization of flowering plants to principles governing active transport in reconstituted systems. This work also provides insights into efforts aimed at designing active transport in synthetic, cell-like systems with capabilities similar to those of real cells.

 More information about our work can be found at https://abelgroup.squarespace.com

— Oghosa H. Akenuwa and Steven M. Abel