SNARE

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<span style="line-height: 1.5em;" />SNARE Proteins<span style="line-height: 1.5em;" /><span style="line-height: 1.5em;" />

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.<span style="line-height: 1.5em;" />

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. 


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].

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.
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