Pregnancy-specific glycoprotein 22 (Psg22)

May have an angiogenic role during early placental development. Binds to cell-surface heparan sulfate proteoglycans (HSPGs), and stimulates secretion of the proangiogenic factors VEGFA and TGFB from uterine dendritic cells and natural killer cells.

Additionally induces endothelial tube formation in vitro. .