Only one way to organize a movement?

Two reports in this issue identify a strikingly similar pattern of coordination between F-actin and microtubule dynamics, suggesting that such coordination may be a basic mechanism by which cells both direct movement and respond to environmental cues.

Previous work had suggested that microtubules mimic F-actin movements in migrating cells, but technological limitations have made this idea difficult to test. On page 31, Salmon et al., studying migrating epithelial cells from newt lung, used new fluorescence speckle microscopy (FSM) imaging techniques to observe the movement of F-actin and microtubules nearly simultaneously in living cells. F-actin moves differently in four zones of the cell. Microtubules oriented parallel to the leading edge precisely mimic F-actin movements in all four zones, whereas microtubules perpendicular to the leading edge are often uncoupled from F-actin movements in two...