EMBO J 30 21, 4479–4488 (2011); published online September 23 2011
NetrinG proteins and NetrinG ligands (NGLs) are adhesive ligand/receptor pairs that influence axon outgrowth and synaptogenesis. In humans, NetrinG mutations are correlated with developmental disorders of cognition, including schizophrenia and Rett syndrome. In this issue of The EMBO Journal, Seiradake et al (2011) report the crystal structures of NetrinGs and NGLs separately and in complex, revealing a remarkable modularity underlying the molecular specificity of NetrinG/NGL interactions.