May play a role in the formation and regulation of the tight junction (TJ) paracellular permeability barrier. Interacts with TJP1/ZO1. Interacts with VAPA. Interacts with CLDN1, CLDN6, CLDN9, CLDN11, CLDN12 and CLDN17. Interacts with PLSCR1. Interacts with LSR, ILDR1 and ILDR2. 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). Dephosphorylated by PTPRJ. Belongs to the ELL/occludin family.