 The cytoplasmic tail contains a PDZ-binding motif that allows it to bind to PDZ containing proteins and interact with them.It contains an Arginine-Glycine-Aspartic Acid (RGD) tripeptide sequence that enables cellular adhesion, through the binding of integrins or other RGD binding receptors that are present in the extracellular matrix (ECM).This RGD sequence on endoglin is the first RGD sequence identified on endothelial tissue.