Homophilic cell adhesion molecule that promotes axonal growth. May play a role in nerve regeneration and in the formation and function of other tissues. Widely expressed. In adult, higher expression in the bone marrow and peripheral blood lymphocytes, medium in the lung, lymph node, thyroid, uterus, thymus, spleen, prostate and skeletal muscle, lower in the liver, placenta, brain, heart and kidney. In embryo, higher expression in the thymus, heart and liver, lower in the spleen, lung, brain and kidney. By nerve injury; in Schwann cells. Belongs to the ninjurin family. Extended N-terminus.