The Spindle Gets Bigger

Although cortical nonmuscle myosin II has long been implicated in cytokinetic aspects of cell division, there has never been strong evidence that it plays a role in the organization of the mitotic spindle. Rosenblatt et al. (2004)([this issue of Cell]) use a number of methods to show that cortical myosin II is in fact important for spindle assembly in higher eukaryotic cells, specifically for the complete separation of centrosomes after nuclear envelope breakdown.