Crosslinked F-actin networks regulate load-dependent energy conversion

Cellular energy conversion from chemical energy to mechanical work underlies essential processes ranging from single-cell division to embryonic development. This energy is primarily derived from the hydrolysis of adenosine triphosphate (ATP), which powers motor proteins to generate forces on the filamentous cytoskeleton. While the load-dependent behaviors of individual motor proteins and ordered muscle fibers are well studied, how motor proteins collectively respond to mechanical load within cellular disordered cytoskeletal networks remains poorly understood. Here, we investigate this by reconstituting purified actomyosin networks crosslinked with various actin crosslinking proteins to mimic cellular environments. We find that structural and mechanical properties of the crosslinked networks, including inter-filament spacing, filament polarity, and network stiffness, modulate load-dependent myosin ATP consumption and inferred mechanical power generation. These findings reveal the intricate role of actin crosslinkers in regulating the mechano-chemical behavior of myosin, offering insight into how cells control energy conversion and force generation through cytoskeletal architecture.