Figure 3.

Structure of tight junctions between 2 adjacent cells. (top) View of a tight junction, by transmission electron microscopy, of an ultrathin section of mouse epididymis reveals focal attachments of adjacent cells, known as ‘kissing points’ (arrows in the image on the right), where the intercellular space is obliterated. Scale bars, 200 nm. (bottom) Schematic representation of adjacent cells where integral membrane proteins of apposing cells obliterate the intercellular space at kissing points. Note that the TJ forms an apical ring around each joined cell. [Adapted with permission from: Mariano C, Sasaki H, Brites D, Brito DM (2011). A look at tricellulin and its role in tight junction formation and maintenance. Eur J Cell Biol 90:787-796. doi:10.1016/j.ejcb.2011.06.005. http://www.sciencedirect.com/science/article/pii/S0171933511001270].