A synaptotagmin suppressor screen indicates SNARE binding controls the timing and Ca²⁺ cooperativity of vesicle fusion
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elife-28409-v2.pdf
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Author(s)
Guan, Zhuo
Bykhovskaia, Maria
Jorquera, Ramon A
Sutton, Roger Bryan
Akbergenova, Yulia
Littleton, J Troy
Date Issued
September 2017
Journal
eLife
Publisher
eLife Sciences Publications, Ltd
Citation
Guan, Zhuo et al. “A synaptotagmin suppressor screen indicates SNARE binding controls the timing and Ca²⁺ cooperativity of vesicle fusion.” eLife 2017, 6 (September 2017): e28409 © Guan et al
Version
Final published version
Abstract
The synaptic vesicle Ca²⁺ sensor Synaptotagmin binds Ca²⁺ through its two C2 domains to trigger membrane interactions. Beyond membrane insertion by the C2 domains, other requirements for Synaptotagmin activity are still being elucidated. To identify key residues within Synaptotagmin required for vesicle cycling, we took advantage of observations that mutations in the C2B domain Ca²⁺-binding pocket dominantly disrupt release from invertebrates to humans. We performed an intragenic screen for suppressors of lethality induced by expression of Synaptotagmin C2B Ca ²⁺-binding mutants in Drosophila. This screen uncovered essential residues within Synaptotagmin that suggest a structural basis for several activities required for fusion, including a C2B surface implicated in SNARE complex interaction that is required for rapid synchronization and Ca²⁺ cooperativity of vesicle release. Using electrophysiological, morphological and computational characterization of these mutants, we propose a sequence of molecular interactions mediated by Synaptotagmin that promote Ca²⁺ activation of the synaptic vesicle fusion machinery.
MIT Department
Massachusetts Institute of Technology. Department of Biology
Massachusetts Institute of Technology. Department of Brain and Cognitive Sciences
Picower Institute for Learning and Memory
Terms of Use
Creative Commons Attribution 4.0 International License
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DOI of Published Version
https://doi.org/10.7554/eLife.28409
