Angiostatin - Angiogenesis inhibitor, derived from plasminogen.

They act by causing apoptosis of endothelial cells, inhibit proliferation of endothelial cells, inhibit migration and endothelial tube formation by inhibiting FGF and VGEF.

They bind to ATP synthase, angiomotin receptors in endothelial surface.

On activation, angiostatin is internalised and activates Focal adhesision kinase (FAK) which in turn reduces phosphorylation of mitogen activated protein kinases. So FGF and VGEF cannot activate the protein kinases.

Angiostatin has been tried as anti-cancer drug, since it can inhibit angiogeneiss in tumor masses and metastases.

It should be noted that ATP synthase (which was considered a mitochondrial enzyme) is present in extra-mitochondrial reigons(cell membranes of endothelial cells). So a highly complex energy production apparatus must be functioning in the endothelial surface. More research is being done to reveal the mystery.