Plays a role in neuronal development and polarity, as well as in axon growth and guidance, neuronal growth cone collapse and cell migration. Necessary for signaling by class 3 semaphorins and subsequent remodeling of the cytoskeleton. May play a role in endocytosis (By similarity). Homotetramer, and heterotetramer with CRMP1, DPYSL3, DPYSL4 or DPYSL5. Interacts through its C-terminus with the C-terminus of CYFIP1/SRA1. Interacts with HTR4. Interacts with CLN6. Interacts with MICALL1 (By similarity). Tightly but non-covalently associated with membranes. Phosphorylation by DYRK2 at Ser-522 is required for subsequent phosphorylation by GSK3B. Phosphorylation at Thr-514 by GSK3B abolishes tubulin-binding leading to destabilization of microtubule assembly in axons and neurodegeneration (By similarity). Belongs to the metallo-dependent hydrolases superfamily. Hydantoinase/dihydropyrimidinase family. Lacks most of the conserved residues that are essential for binding the metal cofactor and hence for dihydropyrimidinase activity. Its enzyme activity is therefore unsure.