Desmosomes

junctions that specifically allow for the influx and efflux of specific ions and molecules within these systems.

The tight junctions are considered extremely tight in situations like the blood-brain barrier, which separates the central nervous system or CNS from the rest of the circulation. There are similar proteins in the retina, which allow for a strong barrier in the eye. Other impermeable states exist in the bladder and skin.

When the tight junctions become dysregulated by inflammation or disease, this can lead to neuroinflammation, diarrhea, leaky gut syndrome, gastritis, irritable bowel syndrome, dermatitis, kidney disease, and even metastatic cancer.

DESMOSOMES

Desmosomes are also referred to as maculae adherens. This means “adhering spot” in Latin. It is a cell to cell adhesion that are seen on the sides of cells. They are relatively strong and are found in tissues that are under certain kinds of mechanical stress, such as bladder tissue, GI tissues, cardiac muscle, and other types of epithelia.

These are made from cadherin proteins, keratin intermediate filaments and linker proteins, which are collectively referred to as desmosome-intermediate filament complexes. Figure 22 shows what a desmosome looks like:

Figure 22.