Desmosomes

Desmosomes are specialized cell junctions that are crucial for the adhesion between certain types of cells, particularly those subjected to mechanical stress, such as epithelial cells, myocardial cells, and others. They are also known as macula adherens. Desmosomes help maintain the structural integrity and cohesion of tissues in multicellular organisms.

Structure

Desmosomes are composed of three major components: the desmoglein and desmocollin (which are types of cadherin proteins), the plaque (a dense area inside the cell membrane where cadherins attach), and the intermediate filaments that connect to the plaque. These components work together to provide strong adhesion between cells. The cadherins extend into the intercellular space to bind with cadherins of adjacent cells, while the plaque and intermediate filaments anchor the junctions to the cytoskeleton of the cell, providing mechanical strength.

Function

The primary function of desmosomes is to resist shearing forces and maintain cellular cohesion within tissues that experience mechanical stress. This is particularly important in tissues such as the epidermis of the skin, where cells are constantly subjected to friction and stretching. In the heart, desmosomes are vital in maintaining the integrity of myocardial cells during the continuous and forceful contractions of the cardiac cycle.

Desmosomes also play a role in cell signaling, influencing pathways that regulate cell proliferation, differentiation, and apoptosis. This is significant in tissue repair and development.

Clinical Significance

Alterations or mutations in the genes encoding desmosomal proteins can lead to a variety of diseases, known as desmosomal diseases. These include skin disorders such as pemphigus vulgaris, which is characterized by blistering due to the loss of cell adhesion in the epidermis, and heart diseases like arrhythmogenic right ventricular cardiomyopathy (ARVC), where the weakening of myocardial cell adhesion leads to heart failure.

Research and Applications

Research on desmosomes has implications for understanding the pathogenesis of desmosomal diseases and developing therapeutic strategies. For instance, treatments targeting the molecular components of desmosomes are being explored for managing pemphigus vulgaris. Additionally, understanding desmosomal dynamics can aid in tissue engineering and the development of biomaterials designed to mimic the adhesive properties of natural tissues.

See Also

• Cell junction
• Epithelium
• Cadherin
• Pemphigus vulgaris
• Arrhythmogenic right ventricular cardiomyopathy