Dynamic analysis of actin distribution using eGFP-actin reporter. Sequential images showing the distribution of eGFP-actin reporter in WT and Cdc42^−/− neutrophils in response to a local source of fMLP (10μM, indicated by X) (30 seconds between each frame). Arrows point to actin protrusions. Note that eGFP-actin remains at one pole of the cell facing the source of fMLP in WT but not in Cdc42^−/− cells. Each set of images are representative of a set of 10. Scale bar represents 5 μm. Fluorescence images were captured at 37°C using a Zeiss Axiovert 200 fluorescence microscope at 40× objective, NA 0.6, with ORCA-ER C4742-95 camera driven Openlab software. The histograms are speed, straightness of migration, and percentage of cells with multiple protrusions and turns of WT and Cdc42^−/− cells expressing eGFP-actin, which were analyzed in a Zigmond chamber assay as in Figure 1 and showed similar results as WT and Cdc42^−/− cells (Figure 1).