Fig. 9. Cargo velocity and load-sharing for a team of two dynein motors permanently attached to their microtubule track.

In panel (a), the average velocity of a cargo driven by a team of two catch-bonding dynein motors is shown as a function of the load force at ATP concentrations of 1mM (circles) and 2mM (squares), and in the absence of catch-bonding (“slip-bond”), i.e. for a positive value of ${\delta }_{\beta }^{+}$ in step 4 (8nm steps) (see Table 1), at 1mM ATP (triangles). To prevent motor detachment in these simulations, we set the detachment rate r_det = 0 (Eq.4). Panels (b-d) show the frequency distributions of the forces acting on the two individual catch-bonding motors for cargo forces of 2pN(b), 5pN(c), and 8pN(d) at 2mM ATP. The distributions are truncated at the load force F_l because the force on an individual motor cannot exceed the load force on the cargo.