Fig. 4.

Doppel interacts with VEGFR2 in brain endothelial cells. (A-C) Proximity ligation assays were performed with control HBMECs (A) or HBMECs expressing doppel (B,C), revealing direct interactions between VEGFR2 and doppel proteins. Red fluorescent signals (right panels) indicate doppel-VEGFR2 protein complexes in HBMECs. (D) Quantitation of doppel-VEGFR2 protein interactions in HBMECs based on proximity ligation assays, *P<0.001. (E) Immunoblot revealing reduced levels of VEGFR2 in HBMECs expressing doppel. Also note that VEGF treatment results in diminished levels of doppel, suggesting VEGF-induced doppel internalization and/or shedding of doppel. Scale bars: 20 µm. A two-tailed Student's t-test was used to quantify the significance of the PLA signal in HBMECs.