SLIT genes encode the secreted ligands used for regulation of axon branching, pathfinding and neuronal migration. The secretory protein Slit homolog 2 (Slit2) and its transmembrane receptor protein Robo1 are evolutionarily conserved molecules thought to regulate axon guidance and neuronal cell migration.
Roundabout homologue 1 (Robo1) is the major Slit2 receptor, used to mediate the function of Slit homologue proteins needed for guiding major forebrain projections during neuronal development. Secreted Slit2 proteins mediate chemorepulsive signals on cells expressing robo1 receptors, allowing the normal growth and migrations of axons in the developing brain. Robo2 is also a receptor protein for the ligand Slit1, with these receptor-ligand interactions being necessary for proper ganglion formation.
Although primarily known for involvement in neuronal signalling, Slit/Robo signalling is involved in cell proliferation and cell mortality in a range of cell and tissue types.