Angiopoietin 1 is a type of angiopoietin and is encoded by the gene ANGPT1.Angiopoietin-1 (Ang1) and Angiopoietin-2 (Ang2) are ligands that regulate tyrosine phosphorylation of the Tie2/Tek receptor on endothelial cells. Proper regulation of Tie2/Tek is required for normal vascular development, by regulating vascular remodeling and endothelial cell interactions. Antiopoietin-2 (Ang2) is an antagonist of Ang1 that competes for binding of the Tie2 receptor and blocks Ang-1 induced Tie2 phosphorylation during vasculogenesis.

Angiopoietins are proteins with important roles in vascular development and angiogenesis. All angiopoietins bind with similar affinity to an endothelial cell-specific tyrosine-protein kinase receptor.