Roundabout family

The Roundabout (Robo) family of proteins are single-pass transmembrane receptors that are highly conserved across many branches of the animal kingdom, from C. elegans to humans. They were first discovered in Drosophila, through a mutant screen for genes involved in axon guidance. The Drosophila roundabout mutant was named after its phenotype, which resembled the circular traffic junctions (see roundabout). The Robo receptors are most well known for their role in the development of the nervous system, where they have been shown to respond to secreted Slit ligands. One well-studied example is the requirement for Slit-Robo signaling in regulation of axonal midline crossing. Slit-Robo signaling is also critical for many neurodevelopmental processes including formation of the olfactory tract, the optic nerve, and motor axon fasciculation. In addition, Slit-Robo signaling contributes to cell migration and the development of other tissues such as the lung, kidney, liver, muscle and breast. Mutations in Robo genes have been linked to multiple neurodevelopmental disorders in humans.