Maintains epithelial barrier function by recruiting MARVELD2/tricellulin to tricellular tight junctions (tTJs) (PubMed:23239027). Crucial for normal hearing by maintaining the structural and functional integrity of tTJs, which are critical for the survival of auditory neurosensory HCs. Mediates fatty acids and lipoproteins-stimulated CCK/cholecystokinin secretion in the small intestine. In the inner ear, may regulate alternative pre-mRNA splicing via binding to TRA2A, TRA2B and SRSF1 (By similarity). Homooligomer (PubMed:15381095). Interacts with MARVELD2 and OCLN; the interaction is required to recruit MARVELD2 to tricellular contacts (PubMed:23239027). Interacts (via C-terminus) with TRA2A, TRA2B and SRSF1 (By similarity). Mainly expressed in prostate and to a lower extent in testis, pancreas, kidney, heart and liver. The disease is caused by variants affecting the gene represented in this entry. Belongs to the immunoglobulin superfamily. LISCH7 family.