Roundabout homologue 1 (Robo1) and Roundabout homologue 2 (Robo2) cooperate to mediate the function of Slit homologue proteins, used in guiding major forebrain projections during neuronal development. Robo2 is a receptor protein for the ligand Slit1, with these receptor-ligand interactions being necessary for proper ganglion formation.
Robo1 and Robo2 are used in separate, specialised processes in post midline crossing axons. Robo1 is needed to prevent axons from stalling immediately post crossing, whereas Robo2 is required for axons to project away from the floor plate and into the lateral funiculus.
Robo2 also plays a key role in the formation of the ureteric bud, during the development of the kidneys. The SLIT-ROBO pathways are involved in the pancreas, however the exact function of this still remains unclear.