Читать книгу Introduction to the Human Cell - Danton PhD O'Day - Страница 29

Because desmosomes show such precise localizations and since they appear to have a consistent structure, we tend to think of them as static and uninteresting structures. This is compounded by other issues: they are linked to tight cell adhesions which maintain tissue integrity in the gut and other areas. But detailed studies using immunolocalization of desmosomes show their localization varies markedly in different normal human tissues. More to the point, these patterns are different when these tissues are infected or diseased. This reorganization of desmosomes is most evident in certain cancers (e.g., pulmonary squamous cell carcinoma). Alterations in desmosomes also underlie various skin disorders. For example, pemphigus vulgaris is an autoimmune disorder causing painful sores and blisters on the skin and in the mouth. It has been shown that sufferers produce antibodies against desmoglein 1 and 3. The presence of these antibodies interferes with the formation and maintenance of desmosomes which are central to the integrity of epithelial layers. The result is a breakdown in the skin. This ailment can also show up in people treated with certain medications such as certain heart drugs (e.g., acetylcholinesterase inhibitors). Other skin disorders are also being found to show desmosomal disruption.

As with other intercellular junctions, the formation and breakdown of desmosomes has other implications to cells especially in signal transduction events that can regulate gene activity. The reason for this is that when proteins are freed from their proper locations, they are then available to do some of the other jobs they might also hold. As detailed above, this can be bad when too much of a specific protein is released by tissue damage or disease. Now let’s move on to discuss some of the specific proteins we’ve mentioned to understand more about how they function and play roles in human infections and diseases.