Adherens junction

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Adherens Junctions are a type of intracellular junction, linking the actin cytoskeleton of cells together[1]. They are points of attachment that help to provide strength and respond to mechanical pressure changes[2]. This kind of junctions are specialized for adhesions between cell and extracellular matrix, as well as adhesions between cells. Most easily seen in epithelial cells, an example of adherens junctions in the body is in cardiac muscle as the association with the actin cytoskeleton enables the contraction and expansion of the heart[3]

Structure 

Adherens junctions are cadherin-mediated adhesive junctions that interact with actin[4].  The space between adjacent membranes at adherens junctions is about 20-25 nm[5]. In epithelial cells, adherens junctions form a continuous belt that surrounds the cell at the apical end of the lateral membrane. Also, adherens junctions share similarities to Desmosomes and Hemi-desmosomes, due to the fact they contain both cadherin and integrin which are transmembrane linkers used in the others[6]. Accordingly, this creates a connection to adjacent cells and extracellular matrix.

The adherens junctions are contsructed from Cadherin proteins, 5 Cadherin molecules are bound together and stabilised by Ca2+ ions. These chain extend beyond the plasma membrane into the extracellular matrix and bind to cadherins on neighbouring cells[7]. The binding to actin is faciliated by Catenin intercellular adaptor proteins[8]

References 

  1. Alberts, Bruce, Molecular Biology of the Cell, 6th Edition, New York, Garland Science, Taylor and Francis Group, 2015.
  2. Alberts, Bruce, Molecular Biology of the Cell, 6th Edition, New York, Garland Science, Taylor and Francis Group, 2015.
  3. John W. Kimball, ‘Junctions Between Cells’, 02/03/15, [cited 17/11/18], available from http://www.biology-pages.info/J/Junctions.html
  4. Wayne M. Becker, Lewis J. Kleinsmith, Jeff Hardin, Gregory Paul Bertoni (2009), The World of the Cell, Pearson International Edition, 7th Edition, P.485
  5. Wayne M. Becker, Lewis J. Kleinsmith, Jeff Hardin, Gregory Paul Bertoni (2009), The World of the Cell, Pearson International Edition, 7th Edition, P.485
  6. Alberts, Bruce, Molecular Biology of the Cell, 6th Edition, New York, Garland Science, Taylor and Francis Group, 2015.
  7. Green KJ, Getsios S, Troyanovsky S, and Godsel LM. Intercellular junction assembly, dynamics and homeostasis, Cold Spring Harb Perspect Biol, 2010 Feb.
  8. Jacqueline M. Benjamin, W. James Nelson, Bench to bedside and back again: molecular mechanisms of α- catenin function and roles of Tumorigenesis, Semin Cancer Biol, 2008 Feb, 18: 01: 53-64.
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