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Dynamic Ca2+-dependent stimulation of vesicle fusion by membrane-anchored synaptotagmin 1.

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.

SUBMITTER: Lee HK

PROVIDER: S-EPMC2994549 | biostudies-literature | 2010 May

REPOSITORIES: biostudies-literature

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Dynamic Ca2+-dependent stimulation of vesicle fusion by membrane-anchored synaptotagmin 1.

Lee Han-Ki HK Yang Yoosoo Y Su Zengliu Z Hyeon Changbong C Lee Tae-Sun TS Lee Hong-Won HW Kweon Dae-Hyuk DH Shin Yeon-Kyun YK Yoon Tae-Young TY

Science (New York, N.Y.) 20100501 5979

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 physi ...[more]

PMID: 20448186

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