Desmosomien

Desmosomes are a type of cell–cell junction that provide strong adhesion between neighboring cells, particularly in tissues that experience mechanical stress, such as the epidermis and cardiac muscle. They help distribute and resist tensile forces, contributing to tissue integrity during stretching and movement.

Structurally, desmosomes consist of transmembrane cadherin proteins—desmogleins (DSG) and desmocollins (DSC)—which mediate extracellular adhesive interactions in a calcium-dependent manner. On the cytoplasmic side, the cadherins connect to dense plaques containing plakoglobin (gamma-catenin) and plakophilins, which in turn bind desmoplakin. Desmoplakin anchors intermediate filaments (keratin in epithelia, desmin in heart) to the desmosome, linking the cell surface to the cytoskeleton.

Desmosomes are part of the macula adherens class of junctions and are often found concentrated at points of strong cell contact. Their arrangement with intermediate filaments, rather than actin, gives cells and tissues substantial mechanical resilience. Assembly and disassembly are dynamic processes regulated by calcium levels, phosphorylation, and cytoskeletal remodeling, allowing tissue remodeling and repair.

Clinical relevance includes autoimmune and genetic disorders. Autoimmune pemphigus vulgaris and foliaceus target desmogleins, leading to loss of cell adhesion and blistering. Hereditary mutations in desmosomal genes (such as DSG2, DSC2, DSP, PKP2, JUP) are associated with skin disorders and arrhythmogenic cardiomyopathy, which can cause cardiac dysfunction and arrhythmias.

Desmosomes differ from hemidesmosomes, which anchor epithelial cells to the basement membrane, and from adherens junctions, which link to actin filaments; desmosomes provide robust connections to intermediate filaments for tensile strength.