Description
Angiopoietin-1 (Ang-1) and Angiopoietin-2 (Ang-2) are closely related secreted ligands which bind with similar affinity to Tie-2. Tie-2 and angiopoietins have been shown to play critical roles in embryogenic angiogenesis and in maintaining the integrity of the adult vasculature. Ang-1 activates Tie-2 signaling on endothelial cells to promote chemotaxis, cell survival, cell sprouting, vessel growth and stabilization. Ang-2 has been identified as a secreted protein ligand of Tie-2 and has alternatively been reported to be an antagonist for Ang-1 induced Tie-2 signaling as well as an agonist for Tie-2 signaling, depending on the cell context