a. The assembly of the mammalian dynein-dynactin-BicD2 (DDB) complex from human dynein, pig-brain dynactin and the N-terminal coiled-coil of mouse BicD2 (BicD2N, 1–400). BicD2N was fused with GFP at its C terminus for attachment of the complex to anti-GFP-coated beads. b. Example trajectories of DDB-driven beads pulled towards the MT plus- (left) and minus- (right) end under 1.5 pN force. The average velocities (mean ± s.e.m.) were calculated from 44 (left) and 27 (right) trajectories. c. Example trajectory of a DDB-driven bead oscillated ± 2.75 pN in a square wave pattern at 10 Hz. Similar to beads driven by S. cerevisiae dynein, DDB processively drives the bead towards the MT minus-end. d. The velocity of DDB-driven beads increases with ΔF in the absence of net force on the bead (mean ± s.e.m.; from left to the right n = 25, 32, 26 from three technical replicates). In comparison, DDB ratcheted faster towards the MT minus-end than S. cerevisiae dynein.