Binds to TEK/TIE2, competing for the ANGPT1 binding site, and modulating ANGPT1 signaling. Can induce tyrosine phosphorylation of TEK/TIE2 in the absence of ANGPT1. In the absence of angiogenic inducers, such as VEGF, ANGPT2-mediated loosening of cell-matrix contacts may induce endothelial cell apoptosis with consequent vascular regression. In concert with VEGF, it may facilitate endothelial cell migration and proliferation, thus serving as a permissive angiogenic signal. Involved in the regulation of lymphangiogenesis. Interacts with TEK/TIE2, competing for the same binding site as ANGPT1. Interacts with ITGA5. Found to be expressed throughout the ovarian cycle. Overexpressed during luteolysis, this could reflect the regression of capillaries that had developed pericyte contact in the midstage corpus luteum. The Fibrinogen C-terminal domain mediates interaction with the TEK/TIE2 receptor.