Tight junctions

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= <span class="Apple-style-span" style="font-size: 13px; ">Tight junctions are those which link cells together; an example of this is epithelial cells to prevent the lipid and protein domains from interacting. &nbsp;They are located between the lateral membranes of cells. &nbsp;This linking means that the cells can form a tissue, for example, the [[Skin|skin]] consists of many layers of [[Epitheial Cells|epithelial cells]] which hold together due to the tight junctions between the cells.</span> =
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Tight junctions are those which link cells together; an example of this is [[Epithelial cells|epithelial cells]] to prevent the [[Lipid|lipid]] and [[Protein domain|protein domains]] from interacting. &nbsp;They are located between the lateral membranes of [[Cells|cells]]. &nbsp;This linking means that the cells can form a tissue, for example, the [[Skin|skin]] consists of many layers of [[Epitheial Cells|epithelial cells]] which hold together due to the tight junctions between the cells.  
  
== Function of Tight Junctions  ==
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=== Function of Tight Junctions  ===
  
Tight junctions are thought to prevent interaction between lipid and proteins laterally across the two domains of the [[Cell membrane|membrane]]. &nbsp;It is also a barrier to prevent certain molecules from leaving the [[Basolateral membrane|basolateral]] side or entering via the [[Apical membrane|apical]] side of the cells. &nbsp;  
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Tight junctions are a type of [[Endothelial Cell-Cell Junction]], responsible for&nbsp;preventing interaction between lipid and proteins laterally across the two&nbsp;[[Cell membrane|membrane]]<span style="line-height: 19.9200000762939px;">&nbsp;</span><span style="line-height: 19.9200000762939px;">domains o</span><span style="line-height: 1.5em;">f neighbouring cells</span><span style="line-height: 1.5em;">. &nbsp;It is also a barrier to prevent certain </span>[[Molecule|molecules]]<span style="line-height: 1.5em;"> from leaving the </span>[[Basolateral membrane|basolateral]]<span style="line-height: 1.5em;"> side or entering via the </span>[[Apical membrane|apical]]<span style="line-height: 1.5em;"> side of the cells, helping to keep the cell polarized<ref>Alberts, B. (2014). Essential cell biology. 4th ed. New York: Garland Pub., p.702.</ref>. Additionally, the apical and basolateral surfaces' separate functions are preserved by the prevention of movement of integral membrane proteins between the surfaces, acheived by the tight junction 'barrier'<ref>Bernd K. Epithelial Cells: Tight Junctions (and other cellular connections); 2010. [cited 16/10/17];
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Available from: http://www.bio.davidson.edu/bernd/Lab/EpithelialInfoWeb/Tight%20Junctions.html</ref>.</span><br>
  
There have been several studies which have provided evidence that there is interaction of the two domains in the absence of tight junctions. For example, sphingomyelin, which is lipophilic, is labelled with bodipy and inserted into the apical membrane of the epithelial cell. &nbsp;In the presence of the tight junctions the sphingomyelin will remain in the apical membrane and not interact with the basolateral surfaces. &nbsp;However, if the tight junctions are disrupted then the sphingomyelin is seen to move to the basolateral membranes thus suggesting that the tight junctions are the reason for the maintanance of the cells [[Polarity|polarity]]. &nbsp;These results are analysed using confocal imaging.
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There have been several studies which have provided evidence that there is interaction of the two domains in the absence of tight junctions. For example, [[Sphingomyelin|sphingomyelin]], which is [[Lipophilic|lipophilic]], is labelled with bodipy and inserted into the apical membrane of the [[Epithelial cell|epithelial cell]]. &nbsp;In the presence of the tight junctions the sphingomyelin will remain in the [[Apical membrane|apical membrane]] and not interact with the [[Basolateral membrane|basolateral]] surfaces. &nbsp;However, if the tight junctions are disrupted then the sphingomyelin is seen to move to the basolateral membranes thus suggesting that the tight junctions are the reason for the maintanance of the cells [[Polarity|polarity]]. These results are analysed using [[Confocal imaging|confocal imaging]].  
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=== References  ===
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<references /><br>

Latest revision as of 19:09, 16 October 2017

Tight junctions are those which link cells together; an example of this is epithelial cells to prevent the lipid and protein domains from interacting.  They are located between the lateral membranes of cells.  This linking means that the cells can form a tissue, for example, the skin consists of many layers of epithelial cells which hold together due to the tight junctions between the cells.

Function of Tight Junctions

Tight junctions are a type of Endothelial Cell-Cell Junction, responsible for preventing interaction between lipid and proteins laterally across the two membrane domains of neighbouring cells.  It is also a barrier to prevent certain molecules from leaving the basolateral side or entering via the apical side of the cells, helping to keep the cell polarized[1]. Additionally, the apical and basolateral surfaces' separate functions are preserved by the prevention of movement of integral membrane proteins between the surfaces, acheived by the tight junction 'barrier'[2].

There have been several studies which have provided evidence that there is interaction of the two domains in the absence of tight junctions. For example, sphingomyelin, which is lipophilic, is labelled with bodipy and inserted into the apical membrane of the epithelial cell.  In the presence of the tight junctions the sphingomyelin will remain in the apical membrane and not interact with the basolateral surfaces.  However, if the tight junctions are disrupted then the sphingomyelin is seen to move to the basolateral membranes thus suggesting that the tight junctions are the reason for the maintanance of the cells polarity. These results are analysed using confocal imaging.

References

  1. Alberts, B. (2014). Essential cell biology. 4th ed. New York: Garland Pub., p.702.
  2. Bernd K. Epithelial Cells: Tight Junctions (and other cellular connections); 2010. [cited 16/10/17]; Available from: http://www.bio.davidson.edu/bernd/Lab/EpithelialInfoWeb/Tight%20Junctions.html

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