AI Article Synopsis
- In neurons, synaptotagmin 1 (Syt1) helps synaptic vesicles fuse with the plasma membrane in response to rising Ca2+ levels, but previous lab tests hadn't fully mimicked this process.
- Using an in vitro fusion assay, researchers discovered that Syt1 anchored to the membrane boosts both the sensitivity to Ca2+ and the speed of fusion.
- However, the effectiveness of Syt1 decreases when Ca2+ levels exceed normal physiological levels, indicating its role as a presynaptic Ca2+ sensor that regulates neurotransmitter release probability.
Article Abstract
In neurons, synaptotagmin 1 (Syt1) is thought to mediate the fusion of synaptic vesicles with the plasma membrane when presynaptic Ca2+ levels rise. However, in vitro reconstitution experiments have failed to recapitulate key characteristics of Ca2+-triggered membrane fusion. Using an in vitro single-vesicle fusion assay, we found that membrane-anchored Syt1 enhanced Ca2+ sensitivity and fusion speed. This stimulatory activity of membrane-anchored Syt1 dropped as the Ca2+ level rose beyond physiological levels. Thus, Syt1 requires the membrane anchor to stimulate vesicle fusion at physiological Ca2+ levels and may function as a dynamic presynaptic Ca2+ sensor to control the probability of neurotransmitter release.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2994549 | PMC |
| http://dx.doi.org/10.1126/science.1187722 | DOI Listing |
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