Fig. 1: Plasmodium kinesin-8B motor domains are MT-dependent ATPases and drive plus-end directed MT gliding.

a Schematic representation of full-length Pbkinesin-8B (PBANKA_020270, top) and Pfkinesin-8B (PF3D7_0111000, bottom) domain organisation, indicating the relationship with the MD construct (the motor domain plus NL sequence); motor domains are coloured green (Pbkinesin-8B) and blue (Pfkinesin-8B), neck linkers are red and coiled-coil regions are yellow. b Both Pbkinesin-8B-MD (top—green) and Pfkinesin-8B-MD (bottom—blue) exhibit MT-stimulated ATPase activity (Pb:GMPCPP-MT, Pf:paclitaxel-stabilised MT). ATPase assay data (n = 3 for each point, mean ± SD) were fitted using the Michaelis-Menten equation, from which the Kcat and K_M were calculated in Prism 9. c Both Pbkinesin-8B-MD (top—green) and Pfkinesin-8B-MD (bottom—blue) exhibit MT-plus end directed gliding activity. For Pbkinesin-8B-MD, the velocity = 41.3 ± 8.8 nm/s (mean ± SD; n = 36), and for Pfkinesin-8B-MD = 44.3 ± 8.4 nm/s (mean ± SD; n = 104). Paclitaxel-stabilised MTs were used and data are plotted on the left, while the representative TIRF-M kymographs on the right shows gliding of a single polarity-marked GMPCPP-MT consistent with plus-end directed motility; MT schematic above.