May be involved in ER stress pathways with effects on lipid homeostasis and insulin secretion (PubMed:33863978, PubMed:23826244). With ILDR1 and LSR, involved in the maintain of the epithelial barrier function through the recruitment of MARVELD2/tricellulin to tricellular tight junctions (PubMed:23239027). Also functions as a B7-like protein family member expressed on immune cells and inflamed tissue and with T-cell inhibitory activity (PubMed:29431694). In the inner ear, may regulate alternative pre-mRNA splicing via binding to TRA2A, TRA2B and SRSF1 (PubMed:28785060). Interacts with MARVELD2 and OCLN (PubMed:23239027). Interacts with P4HB AND HSPA5; the interaction with HSPA5 stabilizes ILDR2 expression (PubMed:33863978). Interacts (via C-terminus) with TRA2A, TRA2B and SRSF1 (PubMed:28785060). Expressed in epithelial tissues, mainly in liver, kidney and colon. Steatotic liver with increased hepatic and circulating triglycerides and total cholesterol. Shows reduced expression of genes mediating synthesis and oxidation of hepatic lipids. Belongs to the immunoglobulin superfamily. LISCH7 family. It is uncertain whether Met-1 or Met-16 is the initiator.