Roundabout (Robo) receptors are a conserved family of four single pass transmembrane proteins¹. All members have multiple immunoglobulin-like domains in the extracellular N-terminal region, three extracellular fibronectin type II domains, and cytoplasmic conserved domains. Robos also undergo preoteolytic processing, important for their signaling process². They serve as receptors for Slit proteins, where upon activation lead to pleiotropic effects including axonal guidance¹, axonal repulsion^3,4, and neural migration⁵.

Slit/Robo signaling mainly prevents axons from migrating to inappropriate locations during the assembly of the nervous system⁶.

Robos are mainly expressed in the nervous system, but are also detected in vascular endothelial and muscle cells⁷. In non-neuronal tissues, Slit/Robo proteins are key oncogenes and tumor suppressors in various types of cancers. Robo1 expression is elevated in breast cancer and colorectal cancer, and has an overall oncogenic role¹.