SNARE

From The School of Biomedical Sciences Wiki
(Difference between revisions)
Jump to: navigation, search
Line 1: Line 1:
= <span style="line-height: 1.5em;" />SNARE Proteins<span style="line-height: 1.5em;" /><span style="line-height: 1.5em;" /> =
+
= SNARE Proteins =
  
<span style="line-height: 1.5em;">SNARE proteins (Soluble N-ethymaleimide- sensitive –factor attachment proteins) are [[Transmembrane proteins|transmembrane proteins]] that are involved in the catalysis of membrane fusion events within the cell by bringing [[Vesicles|vesicles]] together [[Cell_membranes|cell membranes]] and [[Organelle|organelle membranes]]<ref>Berg J., Tymoczko J and Stryer L. (2012) Biochemistry, 7th edition, New York: WH Freeman.</ref>. This process allows for efficient transport of substances ( the vesicles' cargo) within vesicles to their correct final location in the cell.</span><span style="line-height: 1.5em;" />
+
<span style="line-height: 1.5em;">SNARE proteins (Soluble N-ethymaleimide- sensitive –factor attachment proteins) are [[Transmembrane proteins|transmembrane proteins]] that are involved in the catalysis of membrane fusion events within the cell by bringing [[Vesicles|vesicles]] together [[Cell membranes|cell membranes]] and [[Organelle|organelle membranes]]<ref>Berg J., Tymoczko J and Stryer L. (2012) Biochemistry, 7th edition, New York: WH Freeman.</ref>. This process allows for efficient transport of substances ( the vesicles' cargo) within vesicles to their correct final location in the cell.</span>
  
SNAREs are present in organelle membranes and vesicles. There are two types of SNARE protein, v-SNARE ( vesicle SNARE) &nbsp;and t-SNARE (target membrane SNARE). They exist in complementary pairs of a t-SNARE atttched to the membrane of the target organelle and a v-SNARE on the membrane of the vesicle to be released<ref>Alberts B., Johnson A., Lewis J., Raff M., Roberts K., Walter P. (2008) Molecular Biology of The Cell, 5th Edition New York: Garland Science</ref>. The specific v-SNARE on the vesicle recognises the correct t-SNARE and binds to it; in doing so the vesicle is directed to its correct location in the cell. SNARES provide an “extra layer of specificity” to ensure efficient intracellular trafficking.<ref>Alberts B., Johnson A., Lewis J., Raff M., Roberts K., Walter P. (2008) Molecular Biology of The Cell, 5th Edition New York: Garland Science</ref>. This means that a specific v-SNARE will only bind to the specific t-SNARE due to its complementary shape therefore the vesicles are not directed to an incorrect location and the cell is able to use the vesicles' cargo in that specific location.&nbsp;
+
SNAREs are present in organelle membranes and vesicles. There are two types of SNARE protein, v-SNARE ( vesicle SNARE) &nbsp;and t-SNARE (target membrane SNARE). They exist in complementary pairs of a t-SNARE atttched to the membrane of the target organelle and a v-SNARE on the membrane of the vesicle to be released&nbsp;<ref>Alberts B., Johnson A., Lewis J., Raff M., Roberts K., Walter P. (2008) Molecular Biology of The Cell, 5th Edition New York: Garland Science</ref>. The specific v-SNARE on the vesicle recognises the correct t-SNARE and binds to it; in doing so the vesicle is directed to its correct location in the cell. SNARES provide an “extra layer of specificity” to ensure efficient intracellular trafficking.<ref>Alberts B., Johnson A., Lewis J., Raff M., Roberts K., Walter P. (2008) Molecular Biology of The Cell, 5th Edition New York: Garland Science</ref>. This means that a specific v-SNARE will only bind to the specific t-SNARE due to its complementary shape therefore the vesicles are not directed to an incorrect location and the cell is able to use the vesicles' cargo in that specific location.&nbsp;  
  
<br>Once the SNAREs are bound to each other a SNARE complex is formed and the helical domains of the t and v SNAREs wrap around eachother anchoring the vesicle and the [[Plasma membrane|Plasma membrane]]&nbsp;together . The v-SNARE consists of just one protein where as the t-SNARE consists of two or three and it is these proteins which bind together to form the four helix bundle to faclitate&nbsp;[[Exocytosis|Exocytosis]]&nbsp;&nbsp;<ref>Berg J., Tymoczko J and Stryer L. (2012) Biochemistry, 7th edition, New York: WH Freeman.</ref>.<br>  
+
== Fusion ==
 +
 
 +
Once the SNAREs are bound to each other a SNARE complex is formed and the helical domains of the t and v SNAREs wrap around eachother anchoring the vesicle and the [[Plasma membrane|Plasma membrane]]&nbsp;together . The v-SNARE consists of just one protein where as the t-SNARE consists of two or three and it is these proteins which bind together to form the four helix bundle to faclitate&nbsp;[[Exocytosis|Exocytosis]]&nbsp;&nbsp;<ref>Berg J., Tymoczko J and Stryer L. (2012) Biochemistry, 7th edition, New York: WH Freeman.</ref>. The energy needed to carry out exocytosis is thought to come from the energy freed when the membranes are pulled together and water is squeezed out. Fusion, however is not always an immediate process as it relies on an extracellular signal.<ref>Alberts B., Johnson A., Lewis J., Raff M., Roberts K., Walter P. (2008) Molecular Biology of The Cell, 5th Edition New York: Garland Science</ref><br>  
  
 
=== References  ===
 
=== References  ===
  
 
<references />
 
<references />

Revision as of 16:32, 25 November 2014

SNARE Proteins

SNARE proteins (Soluble N-ethymaleimide- sensitive –factor attachment proteins) are transmembrane proteins that are involved in the catalysis of membrane fusion events within the cell by bringing vesicles together cell membranes and organelle membranes[1]. This process allows for efficient transport of substances ( the vesicles' cargo) within vesicles to their correct final location in the cell.

SNAREs are present in organelle membranes and vesicles. There are two types of SNARE protein, v-SNARE ( vesicle SNARE)  and t-SNARE (target membrane SNARE). They exist in complementary pairs of a t-SNARE atttched to the membrane of the target organelle and a v-SNARE on the membrane of the vesicle to be released [2]. The specific v-SNARE on the vesicle recognises the correct t-SNARE and binds to it; in doing so the vesicle is directed to its correct location in the cell. SNARES provide an “extra layer of specificity” to ensure efficient intracellular trafficking.[3]. This means that a specific v-SNARE will only bind to the specific t-SNARE due to its complementary shape therefore the vesicles are not directed to an incorrect location and the cell is able to use the vesicles' cargo in that specific location. 

Fusion

Once the SNAREs are bound to each other a SNARE complex is formed and the helical domains of the t and v SNAREs wrap around eachother anchoring the vesicle and the Plasma membrane together . The v-SNARE consists of just one protein where as the t-SNARE consists of two or three and it is these proteins which bind together to form the four helix bundle to faclitate Exocytosis  [4]. The energy needed to carry out exocytosis is thought to come from the energy freed when the membranes are pulled together and water is squeezed out. Fusion, however is not always an immediate process as it relies on an extracellular signal.[5]

References

  1. Berg J., Tymoczko J and Stryer L. (2012) Biochemistry, 7th edition, New York: WH Freeman.
  2. Alberts B., Johnson A., Lewis J., Raff M., Roberts K., Walter P. (2008) Molecular Biology of The Cell, 5th Edition New York: Garland Science
  3. Alberts B., Johnson A., Lewis J., Raff M., Roberts K., Walter P. (2008) Molecular Biology of The Cell, 5th Edition New York: Garland Science
  4. Berg J., Tymoczko J and Stryer L. (2012) Biochemistry, 7th edition, New York: WH Freeman.
  5. Alberts B., Johnson A., Lewis J., Raff M., Roberts K., Walter P. (2008) Molecular Biology of The Cell, 5th Edition New York: Garland Science
Personal tools
Namespaces
Variants
Actions
Navigation
Toolbox