Lack of Smad or Notch leads to a fatal game of brain pericyte hopscotch.

Pericytes surround and stabilize the vast capillary network of the central nervous system. In this issue of Developmental Cell, Li et al. (2011) show that Smad4 and Notch signaling together regulate endothelial expression of an adhesion factor, N-cadherin, which couples pericytes to the endothelial cell wall, thereby preventing neonatal intraventricular hemorrhage.