Plays a major role in tight junction-specific obliteration of the intercellular space. (Microbial infection) Acts as a receptor for hepatitis C virus (HCV) entry into hepatic cells. Directly interacts with TJP1/ZO-1, TJP2/ZO-2 and TJP3/ZO-3 (By similarity). Interacts with CLDN1, CD81 and OCLN (PubMed:20375010). Expressed in the liver, in peripheral blood mononuclear cells and hepatocarcinoma cell lines. Belongs to the claudin family.