Cadherins are a class of proteins which are expressed on the surface of cells. They play important roles in cell adhesion whereby they ensure cells within tissues are bound together. They are dependent on calcium (Ca²⁺) ions to function, hence their name. A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Cells in culture, stained for keratin (red) and DNA (green) The cell is the structural and functional unit of all living organisms, sometimes called the building blocks of life. ... Schematic of cell adhesion The study of cell adhesion is part of cell biology. ... General Name, Symbol, Number calcium, Ca, 20 Chemical series alkaline earth metals Group, Period, Block 2, 4, s Appearance silvery white Atomic mass 40. ... An ion is an atom or group of atoms with a net electric charge. ...

The cadherin superfamily includes cadherins, protocadherins, desmogleins and desmocollins, and more. Structurally, they share "cadherin repeats", which are the extracellular Ca²⁺ binding domains.

E-cadherin (epithelial) is probably the best understood cadherin. It consists of 5 cadherin repeats in the extracellular domain, one transmembrane domain, and an intracellular domain that binds beta-catenin. The intracellular domain contains a highly phosphorylated region vital to beta-catenin binding and therefore to E-cadherin function. Beta-catenin binds alpha-catenin, which binds to actin so that E-cadherin is joined to the cytoskeleton. Actin (red) profilin (blue) complex Actin is a globular protein that polymerizes helically forming actin filaments (or microfilaments), which like the other two components of the cellular cytoskeleton form a three-dimensional network inside an eukaryotic cell. ...

E-cadherin is first expressed in the 2-cell stage of mammalian development, and becomes phosphorylated by the 8-cell stage, where it causes compaction. In adult tissues, E-cadherin is expressed in epithelial tissues, where it is constantly regenerated with a 5 hour half-life on the cell surface. In zootomy, epithelium is a tissue composed of a layer of cells. ...

Loss of E-cadherin function/expression has been implicated in cancer progession and metastasis. E-cadherin downregulation causes increased invasiveness and cellular motility, allowing cancer cells to cross the basement membrane and invade surrounding tissues. When normal cells are damaged or old they undergo apoptosis; cancer cells, however, avoid apoptosis. ... Metastasis (Greek: change of the state) is the spread of cancer from its primary site to other places in the body. ... The basal lamina (previously called basement membrane) is a layer on which epithelium sits. ...

See also

• protocadherin

External Links

Online Textbook: "Molecular Biology of the Cell" by Bruce Alberts [1].