FIGURE 2:

Mechanical model of axonal MT motility. (A) Schematic of the molecular components of our computational model. Minus-end-directed motors such as cytoplasmic dynein (orange) are immobilized via their cargo domains to long axonal MTs (longer green line) and apply a force that slides a shorter MT in the direction with its plus end leading (plus-end indicated by black tip). Plus-end-directed motors such as kinesin-1 (blue) apply a force to the short MT in the opposite direction. Static cross-linkers (black, zigzag lines) stochastically cross-link MTs, increasing the effective viscous drag force opposing the motion of the short MT. When N_dF_sd > N_kF_sk, dynein motors are the primary drivers of motion, siding the MT with its plus end leading as illustrated here (red arrow). Black arrows indicate the direction and relative magnitude of forces acting on the MT, corresponding to the terms in Eq. 12. (B) Characteristic detachment rate functions described in Eqs. 4 and 8. (C) Linear load-velocity function as described in Eq. 11.