Epithelial cells exhibit a rich variety of molecular interconnections.
One of these is a very specific cell-membrane structure called the adherence junction . Primarily responsible for the junction is E-cadherin, a large protein that spans the membrane such that one end of the protein pokes out of the cell's surface, while the other end projects into the cell's interior. The internal portion hooks into the cell's interior protein skeleton, called the cytoskeleton . Recently, the proteins linking E-cadherin molecules to the cytoskeleton have been identified. These proteins are called catenins .