Cell adhesion, ankyrin-binding protein which may be involved in neurite extension, axonal guidance, synaptogenesis, myelination and neuron-glial cell interactions. A number of isoforms are produced. There is one major 'early' isoform and multiple 'late' isoforms. Around 50 isoforms are found at different developmental stages. N-glycosylated and O-glycosylated. May be proteolytically cleaved at Arg-636. Belongs to the immunoglobulin superfamily. L1/neurofascin/NgCAM family.