The secreted Slit repellents and their Roundabout (Robo) receptors were originally identified as important axon guidance molecules. The SLIT-ROBO interaction has been found to be involved in the regulation of cell migration, cell death and angiogenesis and, as such, has a pivotal role during the development of other tissues such as the lung, kidney, liver and breast []. There are four Robo homologues in vertebrates (Robo1-4).Robo1 and Robo2 are known to play a crucial role in axon guidance [, ]. They overlap to cooperate in guiding longitudinal axons, but each isoform has specialised functions in spinal commissural axon guidance [, ]. Robo1 prevents axonal stalling after crossing []. Robo1 may also be involved in lung []and heart development [, ].Deregulation of Robo is implicated in several neuropathological conditions and cancers [].
