Figure 1

Two molecular motors coupled to a cargo via their elastic stalks or linkers. The motors step forward stochastically and stretch their linkers, thereby inducing an elastic interaction that generates the strain force $F$ [33]. Strong elastic coupling leads to a fast buildup of large forces, whereas weakly coupled motors experience only relatively small forces.Reuse & Permissions

Figure 2

(a) Average binding time $t_2$ and (b) velocity $v_2$ of a cargo pulled by two active motors in units of the single motor binding time $t$ and single motor velocity $v$, respectively. Both quantities are displayed in a colored contour plot as functions of the rescaled single motor stall force $f_s\equiv F_s/F_K$ and the rescaled detachment force $f_d\equiv F_d/F_K$, where the force scale $F_K=Kl$ is the elastic strain force between the motors per motor step. The solid blue line separates the regions with and without a reduced velocity, whereas the solid black line separates the regions of spontaneous and force-induced unbinding. These lines define four distinct transport regimes: (I) weak coupling with essentially unchanged velocity and binding time; (II) strong coupling with both reduced binding time and reduced velocity; (III) reduced velocity with no effect on the binding time; and (IV) enhanced unbinding with no effect on the velocity. The dashed lines correspond to the crossover line as given by (4).Reuse & Permissions

Figure 3

Transport regimes for pairs of different motors characterized by different straight lines $f_d(f_s)=(F_d/F_s)f_s$. We compare kinesin-$1_{\mathrm{Bl}}$ [3], kinesin-$1_{\mathrm{Di}}$ [11], weak dynein, strong dynein, myosin V, and myosin VI; the corresponding single motor parameters are described in Ref. 21. The different transport regimes (I)–(IV) are color coded and separated by crossover points (black diamonds); the precise locations of these points are given in Ref. 21. Each straight line can be explored by varying the elastic coupling strength $\kappa$ and, thus, $f_s=F_s/lK=2F_s/l\kappa$. The star indicates the pair of kinesin motors studied experimentally in Ref. 11.Reuse & Permissions