http://www.creativebiomart.net/description_382671_12.htm

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