May control axon guidance across the CNS (PubMed:28859078). Prevents the delivery of ROBO1 at the cell surface and down-regulates its expression (PubMed:28859078). Interacts (via cytoplasmic domain) with WW domain-containing proteins MAGI1, MAGI3, NEDD4, NEDD4L, WWTR1/TAZ and YAP1. Widely expressed with highest levels in kidney. Gamma-carboxyglutamate residues are formed by vitamin K dependent carboxylation. These residues are essential for the binding of calcium. Belongs to the commissureless family.