Homodimer and heterodimers. Expressed in the root endodermis and flowers. Accumulates exclusively in the root endodermis at a late developmental stage. Strongly expressed in endodermal cells overlaying lateral root primordia and later in a collar of endodermal cells at the base of the emerged lateral root. Also expressed in the floral organ abscission zone in cells that detach along with the shed organs. Belongs to the Casparian strip membrane proteins (CASP) family.