F11R （CD321） is a member of the immunoglobulin superfamily. F11R has a role in epithelial tight junction formation. Tight junctions exemplify one type of cell-to-cell adhesion in epithelial or endothelial cell sheets， establishing continuous seals around cells and acting as a physical barrier to thwart solutes and water from passing easily through the paracellular space. F11R protein can function as a receptor for reovirus， or as a ligand for the integrin LFA1， involved in leukocyte transmigration， or a platelet receptor.
