Thought to act as molecular guidance cue in cellular migration, and function appears to be mediated by interaction with roundabout homolog receptors. During neural development involved in axonal navigation at the ventral midline of the neural tube and projection of axons to different regions. SLIT1 and SLIT2 seem to be essential for midline guidance in the forebrain by acting as repulsive signal preventing inappropriate midline crossing by axons projecting from the olfactory bulb. In spinal cord development may play a role in guiding commissural axons once they reached the floor plate by modulating the response to netrin. In vitro, silences the attractive effect of NTN1 but not its growth-stimulatory effect and silencing requires the formation of a ROBO1-DCC complex. May be implicated in spinal cord midline post-crossing axon repulsion. In vitro, only commissural axons that crossed the midline responded to SLIT2. In the developing visual system appears to function as repellent for retinal ganglion axons by providing a repulsion that directs these axons along their appropriate paths prior to, and after passage through, the optic chiasm. In vitro, collapses and repels retinal ganglion cell growth cones. Seems to play a role in branching and arborization of CNS sensory axons, and in neuronal cell migration. Seems to be involved in regulating leukocyte migration (By similarity). Homodimer. Binds ROBO1 and ROBO2 with high affinity (By similarity). Interacts with GREM1. Detected at E20, between P0 and P10, and in adult in anterior olfactory nuclei, in cortex entorhinal region, hippocampal C3 and dentate gyrus, basal telencephalon septum, hypothalamus ventromedial and preoptic nuclei and dorsal thalamus medial habenula. Detected at E20 in cortex cortical plate. Detected between P0 and P10, and in adult basal telencephalon amygdaloid complex, and diencephalon pretectum optic tract nuclei. Contaminating sequence. Sequence of unknown origin in the C-terminal part.