Probably plays a role in the formation and regulation of the tight junction (TJ) paracellular permeability barrier. Homodimer (By similarity). Interacts with TJP1/ZO1 and SPEF1 (By similarity). Localizes to the apical junction complex composed of tight and adherens junctions. Colocalizes with SPEF1 at sites of cell-cell contact in intestinal epithelial cells. Deletion of the TJP1/ZO1 interaction motif (ZIM) decreases but does not abolish colocalization with TJP1/ZO1. Belongs to the cingulin family.