Desmosomes

Desmosomes (Greek: desmos = connection; soma = body) are plate-like condensations on the lateral walls of cell membranes, which establish a tight connection between two cells like push buttons. Desmosomes occur mainly in cells with intense mechanical stress such as epithelial cells but also in some non-epithelial tissues (e.g. cardiac muscle) and improve mechanical cohesion by connecting the cell's own intermediate filaments with those of other cells.

In epithelial cells these are usually the keratin filaments (tonofilaments) and in cardiac muscle cells desmin filaments. As the intermediate filaments (see cytoskeleton below) continue throughout the cell, they link the desmosome to the cytoskeleton, stabilizing its location on the cell surface.

Protruding through the junction (plaque) are homotypically binding cadherins (desmoglein and desmocollin), which are also anchored in the cytoplasmic plate. They bind in the intercellular space with cadherins from other cells to establish a connection.

Autoantibodies against desmoglein (diseases of the pemphigus group) lead to destruction of the desmosomal adhesion between the cells and to the histological picture of acantholysis.

The intercellular space is partly slightly widened in the area of the desmosomes and filled with filamentous material (glycoproteins and mucopolysaccharides), similar to a putty substance. S.a.u. Hemidesmosomes.