Cytoplasmic dynein is not a conventional processive motor

Here we use the three bead dumbbell assay to show for the first time, that cytoplasmic dynein is a non-processive motor at low ATP concentrations. Processivity can be restored even in the absence of dynactin by increasing the ATP concentration to 100 μM. We propose that an altered occupancy of the different ATP binding sites (AAA1-4) acts as a modulator between processive and non-processive stepping.