Adherens Junction

Interactions of structural proteins at an adherens junction . You can see how the cadherins are connected to actin filaments via various other proteins.

The term adherens junctions , a group of is adherens ( ger .: Adhering junctions ) are summarized. These include zonula adhaerens ( belt desmosome or adhesion belt ), fascia adhaerens (strip desmosome ) and punctum adhaerens (point desmosome) . The adherence connections create a connection between the actin filaments of two cells and thereby strengthen them mechanically.

description

The typical adherence connection occurs in epithelial cells , where an adhesion belt (Zonula Adhaerens) often forms directly below the tight junctions, whereas only point connections are often seen in all other tissues. The proteins involved in all adherence connections are cadherins (Ca ²⁺ dependent transmembrane proteins, which also play an important role in desmosomes ) which are connected to the actin cytoskeleton with various anchor proteins ( catenins , vinculin and α- actinin ). Cadherins are dimers and belong to the homotypic cell adhesion molecules , so they have a specific amino acid sequence for binding another cadherin from another cell for the formation of the cell-cell connection on the extracellular side of the plasma membrane .

In this way, the actin filaments of many cells are joined together to form a transcellular network that can contract with the help of myosin motor proteins. It is believed that this plays a fundamental role in the morphogenesis of animals (especially in the formation of the neural tube ).

It is also assumed that an adherence connection is necessary in order to later form a tight junction.

See also

• Cell contact Overview of the different types of cell contact
• Focal adhesion
• Hemidesmosome
• Gap Junction

Individual evidence

1. ↑ Geiger, B., Volk, T., & Volberg, T .: "Molecular Heterogeneity of Adherens Junctions." In: Journal of Cell Biology . 101, 1985; Pp. 1523-1531.

literature

• B. Alberts, et al .: Molecular Biology of the Cell. Garland Science, 4th edition, 2002, ISBN 0-815-34072-9 .
• Detlev Drenckhahn and Wolfgang Zenker (eds.): Benninghoff Anatomie Volume 1. 15th edition, Urban and Schwarzenberg, Vienna / Munich / Baltimore 1994, ISBN 3-541-00245-X .

photos

• For adherence connections see Figures 32-35
• Electron microscopic images of zonula adhaerens
• Electron microscopic images of the fascia adhaerens

Web links

• Université de Friborg, Département de Médecine: Intercellular connections (with drawings)
• Description of the adherence connections in the chapter "The interaction of desmosomes and adherence connections."