Emergent System Behavior.

A system contains N number of independently configured myosins that each contribute a velocity-dependent time-average force f(v). When a force is applied to the filament F_app, there is a single operating filament velocity v_op found through numerical iteration when the applied force is balanced with myosin contributions:

Emergent system behavior varies with a system’s operating velocity that depends on the structure of myosin isoforms and their organization. Regimes with qualitatively distinct systems behavior are differentiated based on the directionality of a system’s force and average number of attached myosins. A system tends to operate with continuous functionality if at least two myosins are attached on average N_att (v), and implies a system energy E_sys (v) relationship of

with a critical velocity v_c occurring at equality and representing the minimum velocity where continuous system functionality is expected. At lower velocities, the system is assumed to have a high likelihood of dissociation due to periods when no myosins are attached to the filament. Further details for determining emergent system behaviors are in SI Text, sections S2 and S3.