This protein is a cell adhesion molecule involved in neuron-neuron adhesion, neurite fasciculation, outgrowth of neurites, etc. Specifically involved in the development of optic fibres in the retina. Heterodimer of an alpha and a beta chain. Additional isoforms seem to exist. Retina and developing brain. Expressed in developing neural retina and embryonic brain tissue. Belongs to the immunoglobulin superfamily. L1/neurofascin/NgCAM family.