Cell adhesion in desmosomes

A desmosome (also known as macula adherens (Latin for adhering spot ) is a cell structure specialized for cell-to-cell adhesion. Desmosomes, a type of junctional complex, are localized spot-like adhesions randomly arranged on the lateral sides of plasma membranes. They are molecular complexes of cell adhesion proteins and linking proteins that attach the cell surface adhesion proteins to intracellular keratin cytoskeletal filaments. The cell adhesion proteins of the desmosome are members of the cadherin family of cell adhesion molecules. They are transmembrane proteins that bridge the space between adjacent epithelial cells by way of homophilic binding of their extracellular domains to other desmosomal cadherins on the adjacent cell. On the cytoplasmic side of the plasma membrane is a disk-like structure (attachment plaque) composed of very dense materials. The main desmosomal linking proteins, desmoplakins and pakoglobins, bind to the intracellular domain of cadherins and form a connecting bridge to the cytoskeleton. Diagram of desmosomal adhesion. ... Diagram of desmosomal adhesion. ... Cells in culture, stained for keratin (red) and DNA (green). ... Schematic of cell adhesion The study of cell adhesion is part of cell biology. ... A cell junction is a structure within a tissue of a multicellular organism. ... Microscopy of keratin filaments inside cells. ... The eukaryotic cytoskeleton. ... Cadherins are a class of proteins which are expressed on the surface of cells. ... NIGGGGGGGGAAAAAAAAAAAAAAAA PLEASE A transmembrane protein is an integral membrane protein that spans from the internal to the external surface of the biological membrane or lipid bilayer in which it is embedded. ... In zootomy, epithelium is a tissue composed of a layer of cells. ... The eukaryotic cytoskeleton. ...

Desmosomes help to resist shearing forces and are found in simple and stratified squamous epithelium. The intercellular space is very wide (about 30nm).

Blistering diseases

If the desmosomes connecting adjacent epithelial cells of the skin are not functioning correctly, layers of the skin can pull apart and allow abnormal movements of fluid within the skin, resulting in blisters and other tissue damage. Blistering diseases such as Pemphigus vulgaris can be due to genetic defects in desmosomal proteins or due to an autoimmune response. These patients are often found to have antibodies that bind to the desmosomal cadherins and disrupt the desmosomes. For alternate meanings see skin (disambiguation). ... Pemphigus is an autoimmune disorder that causes blistering and raw sores on skin and mucous membranes. ... Genetics (from the Greek genno γεννώ= give birth) is the science of genes, heredity, and the variation of organisms. ... Autoimmune diseases arise from an overactive immune response of the body against substances and tissues normally present in the body. ... Schematic of antibody binding to an antigen An antibody or immunoglobulin is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects like bacteria and viruses. ...

Hemidesmosomes

When visualized by electron microscopy, hemidesmosomes are similar in appearance to desmosomes. Rather than linking two cells, hemidesmosomes attach one cell to the extracellular matrix. Rather than using cadherins, hemidesmosomes use integrin cell adhesion proteins. Hemidesmosomes are asymmetrical and are found in epithelial cells connecting the basal face to other cells. Hemidesmosomes (HD) are very small stud- or rivet-like structures on the inner basal surface of keratinocytes in the epidermis of skin. ... In biology, extracellular matrix (ECM) is any material part of a tissue that is not part of any cell. ... Cadherins are a class of proteins which are expressed on the surface of cells. ... An integrin, or integrin receptor, is an integral membrane protein in the plasma membrane of cells. ...

References

• Green KJ and Jones JC. (1996). "Desmosomes and hemidesmosomes: structure and function of molecular components". The FASEB Journal 10 (8): 871-81. Full text online
• Desmosomes Connect Intermediate Filaments from Cell to Cell in Molecular Biology of the Cell by Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts and Peter Walter (2002) Published by Garland Science. ISBN 0-8153-4072-9

External links

• Histology at luc.edu