Contactins mediate cell surface interactions during nervous system development. Participates in oligodendrocytes generation by acting as a ligand of NOTCH1. Its association with NOTCH1 promotes NOTCH1 activation through the released notch intracellular domain (NICD) and subsequent translocation to the nucleus. Involved in motor coordination (By similarity). Interacts with PTPRG. Expressed in nervous system. Highly expressed in cerebellum. Expressed at intermediate level in thalamus, subthalamic nucleus. Weakly expressed in corpus callosum, caudate nucleus and spinal cord. Belongs to the immunoglobulin superfamily. Contactin family.