Robo4: a guidance receptor that regulates angiogenesis.

During embryogenesis, neural and vascular networks undergo directed patterning, often following the same routes. Several guidance mechanisms, which evolved in order to connect the nervous system, have been adopted by blood vessels. One such system, Slit-Roundabout signaling was first identified by studying axonal growth cones. The identification of an endothelial-specific Roundabout family member, Robo4, led Jones and colleagues to an a priori hypothesis proposing that Robo4 plays a role in regulating vascular patterning. However, they were able to revise this presumptive hypothesis by identifying a role for Robo4 in maintaining vascular stability.