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Updated: Jul 6, 2026

A Direct Force Probe for Measuring Mechanical Integration Between the Nucleus and the Cytoskeleton
Published on: July 29, 2018
Synaptotagmin modulation of fusion pore kinetics in regulated exocytosis of dense-core vesicles
C T Wang1, R Grishanin, C A Earles
1Department of Physiology, University of Wisconsin Medical School, University of Wisconsin, Madison, WI 53706, USA.
Abstract:
In the exocytosis of neurotransmitter, fusion pore opening represents the first instant of fluid contact between the vesicle lumen and extracellular space. The existence of the fusion pore has been established by electrical measurements, but its molecular composition is unknown. The possibility that synaptotagmin regulates fusion pores was investigated with amperometry to monitor exocytosis of single dense-core vesicles. Overexpression of synaptotagmin I prolonged the time from fusion pore opening to dilation, whereas synaptotagmin IV shortened this time. Both synaptotagmin isoforms reduced norepinephrine flux through open fusion pores. Thus, synaptotagmin interacts with fusion pores, possibly by associating with a core complex of membrane proteins and/or lipid.
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