β-TRCP regulates endothelial cell migration and angiogenesis in vitro. (A) HMVECs were exposed to 30 ng/ml VEGF-A where indicated. Recruited cells were photographed after 5 h. Bars, 10 µm. Data shown is representative of three independent experiments. (B) Quantitative measurement of cell migration shown in A. The error bars represent mean ± SD. ***, P < 0.001; n = 3. (C) HMVECs shown in A were subjected to a Matrigel tube formation assay in the presence or absence of 100 ng/ml VEGF-A and photographed after 5 h. Bars, 10 µm. Data shown is representative of three independent experiments. (D) Quantitative measurement of tubes formed in C. The error bars represent mean ± SD. *, P < 0.05; ***, P < 0.001; n = 3. (E) Immunoblot analysis of the HMVECs infected with the indicated shRNA lentiviral vectors. Data shown is representative of two independent experiments. (F) HMVECs shown in E were exposed to 100 ng/ml VEGF-A where indicated. Recruited cells were photographed after 5 h. Bars, 10 µm. Data shown is representative of two independent experiments. (G) Immunoblot analysis of the HMVECs infected with HA-β-TRCP1 where indicated. Data shown is representative of two independent experiments. (H) HMVECs shown in G were subjected to a Matrigel tube formation assay in the presence or absence of 100 ng/ml VEGF-A and photographed after 5 h. Bars, 10 µm. Data shown is representative of two independent experiments.