Cingulin [G6]

A protein component of the submembrane plaque of tight junctions (TJ), contains globular and coiled-coil domains and interacts in vitro with several TJ and cytoskeletal proteins, including the PDZ protein ZO-1. Deletion of the ZO-1 interaction motif (ZIM) decreases but does not abolish colocalization with ZO-1. Diffusion of solutes is prevented across certain barriers by the formation of tight junction seals. Occludin and Cingulin interact with other proteins to direct the formation and regulation of tight junctions. Cingulin binding has also been shown to inhibit RhoA activation and signaling with increased Cingulin expression in confluent cells, causing downregulation of RhoA by inhibiting GEF-H1/Lfc. Probably plays a role in the formation and regulation of the tight junction (TJ) paracellular permeability barrier. Localized on the cytoplasmic face of tight junctions of polarized epithelia and some endothelia. Expressed in pancreas, kidney, liver, bladder, small intestine and lung, but not in skeletal muscle, placenta, brain or heart.