KRX-725-induced internalization of S1P₃. HUVECs were grown overnight with 2% c-FCS and incubated with vehicle (0.1% DMSO), S1P (1 μM), and KRX-725 (20 μM) for 45 minutes. Cells were fixed with 4% paraformaldehyde, permeabilized, blocked, and immunostained with anti-EDG1 and EDG3-NT antibodies, followed by Cy3- and FITC-labeled secondary antibodies, respectively. Visualization was done using confocal microscope using × 63 objective.