Dynein shifts into second gear

Abstract

Although dynein, a microtubule-based molecular motor, has a respectable 40-plus-year research history, only recently has it begun to yield the innermost secrets of how it operates. Current efforts address how the bulky motor domains coordinate their activity to make processive steps along a cytoplasmic microtubule (1–3), suggest that the motor can vary its step size (4), and even demonstrate that dynein can run backward (5). The article by Shima et al. (6) in this issue of PNAS reveals another exceptional property of dynein, namely that the motor has more than one mode of force production. Such a discovery reinforces the view that dynein is more than a simple motor, perhaps indicating that further surprises are yet to come.