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Cell Rep. 2017 Aug 8;20(6):1348-1359. doi: 10.1016/j.celrep.2017.07.040.

The Presynaptic v-ATPase Reversibly Disassembles and Thereby Modulates Exocytosis but Is Not Part of the Fusion Machinery.

Author information

1
Department of Cellular Biophysics, Institute of Medical Physics and Biophysics, University of Münster, Robert-Koch-Str. 31, 48149 Münster, Germany.
2
Department of Cellular Biophysics, Institute of Medical Physics and Biophysics, University of Münster, Robert-Koch-Str. 31, 48149 Münster, Germany. Electronic address: kahms@uni-muenster.de.
3
Department of Cellular Biophysics, Institute of Medical Physics and Biophysics, University of Münster, Robert-Koch-Str. 31, 48149 Münster, Germany; IZKF Münster and Cluster of Excellence EXC 1003, Cells in Motion (CiM), Münster, Germany. Electronic address: klingauf@uni-muenster.de.

Abstract

Vacuolar H+-ATPase (v-ATPase) is a multi-subunit complex comprising two domains: the cytosolic V1 domain catalyzing ATP hydrolysis and the membranous V0 sector translocating protons across membranes. In addition to proton pumping, a direct function of the V0 proteolipid ring in membrane fusion has been proposed for yeast vacuolar fusion and synaptic vesicle exocytosis in Drosophila. Here, we show in cultured hippocampal neurons that in recycling synaptic vesicles, v-ATPases are only transiently assembled in a pH-dependent fashion during the tightly coupled cycle of exo-endocytosis. Upon locking v-ATPase in an assembled state by saliphenylhalamide, we observed use- and time-dependent release depression for stimuli exceeding release of primed vesicles but no abrogation of exocytosis. Thus, the membranous V0 sector is not part of the exocytotic fusion machinery. Instead, v-ATPase modulates release upstream of docking to favor fusion of fully filled synaptic vesicles.

KEYWORDS:

exocytosis; fusion machinery; reversible disassembly; synaptic vesicle recycling; v-ATPase

PMID:
28793259
DOI:
10.1016/j.celrep.2017.07.040
[Indexed for MEDLINE]
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