From the Guidelines
Desmosomes and hemidesmosomes are distinct cell junction structures that serve different functions, with desmosomes connecting adjacent cells and hemidesmosomes anchoring cells to the basement membrane, as highlighted in a recent study 1.
Key Differences
- Desmosomes connect adjacent cells to each other, forming strong adhesions between neighboring cells in tissues that experience mechanical stress, such as the skin and heart, and consist of cadherin proteins that interact in the extracellular space and connect to intermediate filaments via plaque proteins 1.
- Hemidesmosomes, on the other hand, anchor epithelial cells to the underlying basement membrane, containing integrin proteins that bind to laminin and connect to keratin intermediate filaments via plaque proteins 1.
Clinical Implications
- Disruption of these structures can lead to various diseases, including pemphigus, which is caused by autoimmune targeting of desmosomes, and certain forms of epidermolysis bullosa and pemphigoid, which are associated with hemidesmosome dysfunction 1.
- Understanding the differences between desmosomes and hemidesmosomes is crucial in diagnosing and treating diseases involving epithelial integrity and cell adhesion, as highlighted in a study on the management of bullous pemphigoid 1.
Structural Composition
- The epidermis, the outermost layer of the skin, is subdivided into several strata, including the stratum basale, which is joined by hemidesmosomes, and the stratum spinosum, which is composed of cells connected by desmosomes 1.
- The distinct structures and functions of desmosomes and hemidesmosomes are essential for maintaining tissue integrity and preventing disease, as emphasized in a study on the guidelines and definitions for research on epithelial-mesenchymal transition 1.
From the Research
Desmosomes
- Desmosomes are intercellular adhesive junctions of epithelial cells that contain two major transmembrane components, desmogleins (Dsg) and desmocollins, which are both cadherin-type cell-cell adhesion molecules 2
- Desmosomes provide mechanical strength to intercellular adhesion and are abundant in tissues subjected to significant mechanical stress, such as stratified epithelia and myocardium 3
- Desmosomal adhesion is based on the Ca(2+)-dependent, homo- and heterophilic transinteraction of cadherin-type adhesion molecules, and desmosomal cadherins are anchored to the intermediate filament cytoskeleton by adaptor proteins of the armadillo and plakin families 3
Hemidesmosomes
- There is no direct information available in the provided studies to describe hemidesmosomes and compare them to desmosomes
Comparison and Diseases
- Desmosomes are dynamic structures subjected to regulation and are targets of signalling pathways that control their molecular composition and adhesive properties, and disturbed desmosomal adhesion contributes to the pathogenesis of diseases such as pemphigus 3
- Pemphigus is a severe autoimmune-blistering disease of the skin and mucous membranes caused by autoantibodies reducing desmosomal adhesion between epithelial cells, and autoantibodies against desmogleins (Dsgs) 1 and 3 as well as desmocollin 3 have been shown to be pathogenic 4
- A detailed understanding of the molecular alterations causing desmosomal dysfunction has underpinned the development of novel diagnostic tools, with salient clinical implications for dentists and oral medicine practitioners because the majority of desmosomal diseases affect the oral cavity 5
- Desmosomes have been implicated in three main disease types: autoimmune diseases, congenital diseases that affect intracellular calcium channels, and congenital diseases that directly affect desmosomal structural components 6