Contactins mediate cell surface interactions during nervous system development. Has some neurite outgrowth-promoting activity in the cerebral cortical neurons but not in hippocampal neurons. Probably involved in neuronal activity in the auditory system (By similarity). Interacts with PTPRG. Expressed in brain and kidney and at very low level in placenta. Not expressed in other tissues. In brain, it is highly expressed in the occipital lobe, amygdala, cerebral cortex, frontal lobe, thalamus and temporal lobe. Expressed at moderate level in the cerebellum, substantia nigra, putamen, medulla and hippocampus. Weakly expressed in the spinal cord and caudate nucleus. Weakly or not expressed in the corpus callosum. Belongs to the immunoglobulin superfamily. Contactin family. Truncated C-terminus.