Figure 5. S1P inhibits macropinocytosis of FITC-labeled dextran via the S1P₂ receptor subtype.

XS52 cells were transfected with siRNA against S1P₂ or control siRNA and silencing was detected by quantitative real time PCR (A). Transfected and control cells were incubated with FITC-labeled dextran in the presence or absence of S1P (5 µM) for 15 min and macropinocytosis was detected by flow cytometry. Relative endocytosis are expressed as the mean ± SEM of results from at least three independent experiments. **P < 0.01 indicate a statistically significant difference vs. control experiments (B). Transfected or control cells were treated with S1P (5 µM) for 15 min followed by the detection of Akt activity (C). Values of the densitometric analysis are expressed as x-fold decrease of p-Akt formation compared to untreated cells ± SEM from three experiments. **P<0.01 indicates a statistically significant difference versus control (C).