Plays a major role in tight junction-specific obliteration of the intercellular space, through calcium-independent cell-adhesion activity. Expressed in all sensory epithelia of the inner ear vestibular organs, as well as in liver and kidney. At postnatal day 4, expression is apically located in the inner and outer hair cell region of the entire organ of Corti. By postnatal day 8, expression is highest in the supporting cells of the organ of Corti. Belongs to the claudin family.