The C-terminus of kinesin-14 Ncd is a crucial component of the force generating mechanism

Ncd, a member of kinesin-14 family motors, uses the power stroke, a lever-like pivoting action of a long and stiff element, to exert force and generate movement. To better understand the role of the Ncd C-terminus in this process we produced four Ncd mutants in which this segment was altered or deleted. For these proteins we measured their affinity to the microtubule, steady-state ATPase and gliding velocity in multiple motor assays. The mutations had a dramatic effect on all three parameters measured, suggesting that the C-terminal residues of Ncd play an important role in modulating the interaction of the motor with the microtubule.