Tight-junction protein required for paracellular chloride transport in the kidney. Mediates recruitment of CLDN4 to tight junction in the kidney. Claudins play a major role in tight junction-specific obliteration of the intercellular space, through calcium-independent cell-adhesion activity. Directly interacts with TJP1/ZO-1, TJP2/ZO-2 and TJP3/ZO-3. Interacts with CLDN4. Interacts with KLHL3. Localizes to tight junctions in all 3 segments of the epididymis, in the caput found in the lateral margins of principal cells, and in the corpus at the interface between basal and principal cells. Expressed in the epididymis, mainly in the caput segment. Ubiquitinated by the BCR(KLHL3) E3 ubiquitin ligase complex in the kidney, leading to its degradation. A protein of the expected size has been detected by antibody binding and Western blot in at least one of the analyzed tissues or cells. Belongs to the claudin family.