By binding to and “walking along” microtubules of the mitotic spindle, Kinesin-14 motor proteins coordinate accurate chromosome segregation during mitosis (cell division). Scientists had long believed that human Kinesin-14 HSET is “processive,” meaning it takes multiple steps along a microtubule without dissociating (i.e., disengaging from their microtubule track). Now, Albert Einstein College of Medicine researchers led by Arne Gennerich, Ph.D., have conclusively shown that mitotic Kinesin-14 motors are