βPix plays a dual role in cerebral vascular stability and angiogenesis, and interacts with integrin αvβ8

► The scaffold protein β Pix requires Git1-binding ability to stabilize blood vessels. ► Knockdown of β Pix , Git1 or Integrin αvβ8 results in hemorrhage. ► β Pix and Integrin αvβ8 promote cerebral angiogenesis. ► β Pix and Integrin αvβ8 promote proliferation of endothelial and mesenchymal cells. ► Loss of β Pix or Integrin αvβ8 leads to lower vascular mural cell marker expression.