So there are different types of claudine proteins. Now, what exactly are the functions of the tight junction connection? So there are two major functions. Notice that each side of the cell, let's say, on the lumen side, contains a certain type of integral proteins or certain types of integral proteins. And the basilateral side, this side also contains its share of different types of integral proteins, proteins that basically allow the passageway of different types of ions and molecules. And what the Thai junctions do.