Fig. 5. Recruitment of zyxin into FX occurs following local retraction of the lamellipodium. Endothelial cells were cotransfected with YFP-paxillin and CFP-zyxin. Time-lapse two-color movies captured the differential dynamic behavior of these proteins in migrating cells. A series of merged images from such a movie is presented here, where paxillin is shown in red and zyxin in green (see also Movie 2: http://jcs.biologists.org/supplemental/). Arrows mark the direction of leading edge movement and empty circles mark a static state. Notice that while FA contain both paxillin and zyxin (yellow) the array of FX in the advancing lamella contain paxillin alone (red). One minute after the onset of retraction (time point 5') zyxin is seen entering the FX, which grow centripetally to become FA. Scale bar: 5 µm.