Angiopoietin 4, also known as ANG-4 or ANGPT4, is a protein belongingto the angiopoietin family and is highly expressed inthe lung with much lower levels found in other tissues. Angiopoietin 4 / ANG-4 / ANGPT4 is a protein withimportant roles in vascular development and angiogenesis. All angiopoietins bind with similar affinity to anendothelial cell-specific tyrosine-protein kinasereceptor. The mechanism by which they contribute to angiogenesis is thought toinvolve regulation of endothelial cell interactions with supporting perivascular cells. The protein encoded by thisgene functions as an agonist and is an angiopoietin. Angiopoietin 4 secreted ligand for the vascular endothelial restricted receptortyrosine kinase TEK,including phosphorylation of TEK,promoting angiogenic remodeling as well as vesselmaturation and stabilization,predominantly expressed in lung.