Netrin-G1 ligand (NGL1) is a transmembrane protein containing leucine-rich repeat (LRR) and immunoglobulin (Ig) domains that specifically interact with netrin-G1 through its LRR region. Whereas netrin-G1 is expressed highly in mouse thalamic axons, NGL1 is most abundant in the striatum and the cerebral cortex. NGL1 is implicated in facilitating axonal growth of the vertebrate CNS. Membrane-bound netrin-G1 acts as an axonal receptor, whereas the LRR-containing transmembrane protein NGL1 acts as a ligand in promoting the growth of thalamic axons.