May play a role in the formation and regulation of the tight junction (TJ) paracellular permeability barrier. It is able to induce adhesion when expressed in cells lacking tight junctions. (Microbial infection) Acts as a coreceptor for hepatitis C virus (HCV) in hepatocytes. Interacts with TJP1/ZO1 (PubMed:19017651). Interacts with VAPA (PubMed:10523508). Interacts with CLDN1, CLDN6, CLDN9, CLDN11, CLDN12 and CLDN17 (PubMed:20375010). Interacts with PLSCR1 (PubMed:21806988). Interacts with LSR, ILDR1 and ILDR2 (PubMed:23239027). Localized at tight junctions of both epithelial and endothelial cells. Highly expressed in kidney. Not detected in testis. The C-terminal is cytoplasmic and is important for interaction with ZO-1. Sufficient for the tight junction localization. Involved in the regulation of the permeability barrier function of the tight junction (By similarity). The first extracellular loop participates in an adhesive interaction. Dephosphorylated by PTPRJ. The tyrosine phosphorylation on Tyr-398 and Tyr-402 reduces its ability to interact with TJP1. Phosphorylation at Ser-490 also attenuates the interaction with TJP1. The disease is caused by variants affecting the gene represented in this entry. Belongs to the ELL/occludin family. Occludin entry