Angiopoietin belongs to the VEGF protein family that takes part in postnatal and embryonic angiogenesis. Angiopoietin proteins regulates growth, chemotactic activity and functional behavior of vascular endothelial cells and take part in angiogenesis. Angiogenesis is the mechanism for the production of novel blood vessels via sprouting from existing blood vessels in a procedure that includes the proliferation and migration of endothelial cells from preexisting vessels. The growth of blood vessel growth takes place in the embryo and infrequently in adult. Proteins which belong to the angiogenesis family take part in endothelial lining, disassembling, assembling of blood vessels. ANGPTL1 is crucial for vessel survival, maturation, migration and adhesion. ANGPTL2 disrupts vascularization and activates cell death though the reaction of ANGPTL2 with VEGF result in the proliferation of neo-vascularization.
ANGPT2 is an antagonist for TIE2 and ANGPT1, which interferes the vascular production ability of ANGPT1. ANGPT2 stimulates endothelial cell apoptosis. In the absence of ANGPT1, ANGPT2 can produce tyrosine phosphorylation of TEK/TIE2. ANGPTL2 and VEGF together assist the proliferation and endothelial cell migration therefore act as a tolerant angiogenic signal.
Angiopoietin proteins modulate vasodilation, microvascular permeability, and vasoconstriction through signaling the smooth muscle cells that are adjacent to the vessels. The 4 recognized angiopoietins are: ANGPT1, ANGPT2, ANGPT3 and ANGPT4.
Tissues discharge angiogenic factors that stimulate angiogenesis due to poor blood supply conditions through pathological angiogenesis and typical processes. Angiogenic Proteins are activated by connective tissue, tumor and inflammatory cells in reaction to hypoxia. Proteins which belong to the Angiogenesis family are effected by genetic background thus responsible for diseases that take part in the production of new blood vessels.