In an in vitro tug of war, myosin Va dominates its myosin VI partner 79% of the time, with the losing motor stepping backward in synchrony with the winning motor.
This in vitro model demonstrates physical communication and synchronized stepping between opposing molecular motors bound to a common cargo.
Myosin Va (myoV) and myosin VI (myoVI) are processive molecular motors that transport cargo in opposite directions on actin tracks. Because these motors may bind to the same cargo in vivo, we developed an in vitro "tug of war" to characterize the stepping dynamics of single quantum-dot-labeled myoV and myoVI motors linked to a common cargo. MyoV dominates its myoVI partner 79% of the time. Regardless of which motor wins, its stepping rate slows due to the resistive load of the losing motor (myoV, 2.1 pN; myoVI, 1.4 pN). Interestingly, the losing motor steps backward in synchrony with the winning motor. With ADP present, myoVI acts as an anchor to prevent myoV from stepping forward. This model system emphasizes the physical communication between opposing motors bound to a common cargo and highlights the potential for modulating this interaction by changes in the cell's ionic milieu.
Ali et al. (Mon,) reported a other. Coupled myosin Va and myosin VI motors vs. Single uncoupled motors was evaluated on Motor dominance (direction of movement). In an in vitro tug of war, myosin Va dominates its myosin VI partner 79% of the time, with the losing motor stepping backward in synchrony with the winning motor.