Figure 6.
Effect of expression of SphK1 on internalization of endogenous S1P1. RBL-2H3 cells stably expressing vector (A) or SphK1 (B) were cultured in the presence of 15% serum for 24 hours and then treated with vehicle or S1P (100 nM) for 30 minutes. Cells were fixed, incubated with anti-S1P1 primary antibody (1:100), and examined by confocal microscopy after staining with Texas Red-conjugated secondary antibody or by DIC to visualize the cells. (C) RBL-2H3 cells stably expressing SphK1 were cultured in serum-free medium for 24 hours and then treated as described for panels A and B. Right panels show merged pictures. Representative images from over 30 cells examined are shown.
