Tight junctions (blue dots) between cells are connected areas of the plasma membrane that stitch cells together. Adherens junctions (red dots) join the actin filaments of neighboring cells together.

The lateral surfaces of epithelial cells also contain several other types of specialized junctions. Tight junctions form a seal between cells that is so strong that not even ions can pass across it.

At least three types of junctions are known ... succeeded in generating an epithelial cell line that specifically and completely lacks tight junction membrane proteins claudins and JAM-A, and ...