Based on limited published evidence, CLDN22 (claudin 22) is a tight junction protein that plays a major role in obliterating intercellular space through calcium-independent cell-adhesion activity. It functions as a four-transmembrane protein containing the conserved WWCC motif characteristic of the claudin family 1. CLDN22 localizes to the plasma membrane and bicellular tight junctions, where it mediates protein binding and cell-cell adhesion. The gene is located on human chromosome 4.1 1.