SNARE Complexes and their Important Role with Vesicle Fusion and Docking SNARE complex’s play a role in all vesicle fusion within the cell including going from the endoplasmic reticulum to the golgi body and golgi body to lysosomes or to mitigate exocytosis of intracellular vesicles with the cellular membrane. The SNARE complex is made up of 2 classes of protiens that allow vesicle fusion called the v-snares and t-snares. The v-snares are found on the vesicle and include synaptobrevin. The t-snares are located on the target membrane and has two components called syntaxin and SNAP-25 (Karp, 2008). The SNARE proteins are fixed tightly within the vesicle and target membrane by transmembrane domains. When the target membrane and vesicle come into contact and dock with each other the SNARE motifs composed of four alpha helices interact with each other and make a strong interwoven linkage (Wu et al., 2012). The zipper hypothesis says that the linkage of the t-snare and v-snare start assembling from the vesicle membrane and continue to intertwine or “zipper” down to the target membrane (Knecht and Grubmüller, 2003). The alpha helices pull tightly to each other causing the membranes to come in close proximity and membrane fusion is stimulated. The paper, All three components of the neuronal SNARE complex to secretory vesicle docking, by Wu et al., wanted to know how synaptobrevin, SNAP-25, and syntaxin were involved with vesicle and target membrane docking. In the paper they performed a number of experiments to test how SNARE proteins contributed to docking. To determine if the v-snare synaptobrevin has a role to play in vesicle docking the amount of functional synaptobrevin was reduced via the addition of the neurotoxin botulinum (BoNT/d) which was labeled with an in-vector marker called DsRed into the cells. The neurotoxin botulinum (BoNT/d) cleaves the v-snare synaptobrevin. An Immunoblot experiment was performed to make sure the...
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