Fig. 5.

Ang2 inhibits enhanced Ang1-activation of Tie2. Endothelial cells were treated with control vehicle or 10 ng/ml PMA before addition of 50 ng/ml Ang1 in the absence and presence of 1000 ng/ml Ang2 for 30 min as indicated. Cells were lysed and immunoprecipitated with anti-Tie2 antibodies. Phosphorylated Tie2 (pTie2) was detected by immunoblotting with anti-phosphotyrosine antibodies following SDS/PAGE. Blots were stripped and re-probed with anti-Tie2 antibodies. Tie2 phosphorylation was determined in three independent experiments. Data is presented as means and SEM of pTie2/Tie2 ratio normalized to that of PMA plus Ang1. ⁎ indicates statistically significant difference between control and Ang1 stimulated cells, † indicates significant inhibition of Ang1 induced phosphorylation by Ang2 and # indicates significant enhancement of Ang1-induced phosphorylation by PMA (p < 0.05, Student's t test).