Anti-angiogenesis is anti-actin

Blood vessel growth is suppressed by several proteins—such as endorepellin—that are anti-angiogenic only after they are generated as fragments of larger proteins. Now, Bix et al. (page 97) report two surprises of endorepellin action: it exerts its effects via an integrin that collagen I uses to promote angiogenesis; and it may operate via a heat shock protein to disassemble actin structures needed for motility.

Endorepellin is a COOH-terminal fragment of perlecan, a heparan sulfate proteoglycan that acts as a cofactor for pro-angiogenic factors such as FGF. The authors found that a segment of endorepellin was enough to prevent endothelial cell migration and formation of capillaries, and that it acted by disrupting the actin cytoskeleton and attachment sites. They found that the major functional receptor for endorepellin was...