Kinesin-5 motors are bipolar homotetramers with two motor domains at each end, separated by a stalk/tail region (Cole et al. 1994). During mitosis, Kinesin-5 motors function near the spindle midzone to maintain pole to pole distance. Motor domains attach to microtubules from opposite poles and translocate towards the plus ends, thereby pushing the spindle poles apart (Kapitein et al. 2005). Kinesin-5 is also involved in axon growth (Myers & Baas 2007).