Description
Angiopoietin 2 and -1 are involved in the development of the endothelium by regulating tyrosine phosphorylation of the membrane receptor Tie 2. Angiopoietin 2 is only 60% homologous with -1. It is a naturally occurring antagonist of ANGPT1 that competes for binding to the TIE2 receptor and blocks ANGPT1-induced TIE2 autophosphorylation. ANGPT1 binding to Tie 2 causes phosphorylation of the receptor. Angiopoietin 2 competes for this binding, and thus blocks receptor phosphorylation. Angiopoietin 2 expression occurs at sites of vascular remodelling: dorsal aorta and major aortic branches, ovary, placenta and uterus