TJP1 is a protein located on a cytoplasmic membrane surface of intercellular tight junctions. TJP1 may be involved in signal transduction at cell-cell junctions.This gene encodes a protein located on a cytoplasmic membrane surface of intercellular tight junctions. The encoded protein may be involved in signal transduction at cell-cell junctions. Two transcript variants encoding distinct isoforms have been identified for this gene.