Lamellae lead the way

Open any cell biology text and it is clear that lamellipodia, the ruffled edges of motile cells, initiate movement. So it may come as a surprise that Gupton et al. can disrupt this domain without blocking cell movement (page 619). In fact, cells move faster without lamellipodia. The driving force for movement appears to come from the lamella, the structure that lies just proximal to the lamellipodium.

Previously, the team examined the lamella and lamellipodia using quantitative fluorescent speckle microscopy (qFSM), a technique that allows for deconvolution of images of physically overlapping cell domains. The domains have distinct molecular components, filament–assembly kinetics, and motion. Moreover, although the lamellipodia moved forward and backward repeatedly in the axis of cell movement, the team saw hints that cells made forward progress only when...