Contactins mediate cell surface interactions during nervous system development. Has some neurite outgrowth-promoting activity. May be involved in synaptogenesis. Interacts with PTPRG. Expressed in the region of developing olfactory neurons. Isoform 2 is expressed in mature sensory cells of the vomeronasal neuroepithelium and at lower level in olfactory neuroepithelium. Expressed from 14 dpc at a time when developing axons reach the olfactory bulb. Belongs to the immunoglobulin superfamily. Contactin family.