Loss of focal RhoA activity in Amot-deficient endothelial cells. FRET images of endothelial cells expressing the Raichu-RhoA YFP-CFP probe. FRET efficiency is displayed as a thermal map corresponding to the scale shown in lower panels. Randomly migrating Amot wt cells exhibited high RhoA activity in the leading front of lamellipodia and cellular protrusions. In contrast, the RhoA activity in Amot-deficient cells was not focal but was uniformly localized to the outer membrane. Scale bar represents 10 μm.