Loss of RASIP1 increases junction remodeling. (A) Time course of FAJ formation after EGTA treatment and cBiMPs stimulation. In control cells stained with VE-cadherin, linear junctions decay into an equilibrium of linear and FAJs (white arrows indicate a subset of FAJs). In RASIP1 KD HUVECs, FAJs appear earlier (∼1-2 hours post-cBiMPs) and accumulate more rapidly, culminating in an increased proportion of FAJs at steady state. (B) Quantification of FAJ/linear junction ratios in 3 experiments. (C) Whole-mount immunofluorescence staining of VE-cadherin in control and Rasip1^−/− yolk sacs at E9. FAJs (white arrows) are increased in knockout yolk sacs, mirroring the in vitro finding. (D) Quantification of FAJ/linear junction ratios in yolk sacs from 2 separate litters of E9 embryos. Litter 1: n = 3 control, 4 Rasip1^−/− embryos. Litter 2: n = 5 control, 2 Rasip1^−/− embryos. Red asterisks denote statistical significance vs control groups. P < .01 (unpaired Student t test). Scale bars: 10 μm.