title: A single vesicular glutamate transporter is sufficient to fill a synaptic vesicle.
abstract: Quantal size is the postsynaptic response to the release of a single synaptic vesicle and is determined in part by the amount of transmitter within that vesicle. At glutamatergic synapses, the vesicular glutamate transporter (VGLUT) fills vesicles with glutamate. While elevated VGLUT expression increases quantal size, the minimum number of transporters required to fill a vesicle is unknown. In Drosophila DVGLUT mutants, reduced transporter levels lead to a dose-dependent reduction in the frequency of spontaneous quantal release with no change in quantal size. Quantal frequency is not limited by vesicle number or impaired exocytosis. This suggests that a single functional unit of transporter is both necessary and sufficient to fill a vesicle to completion and that vesicles without DVGLUT are empty. Consistent with the presence of empty vesicles, at dvglut mutant synapses synaptic vesicles are smaller, suggesting that vesicle filling and/or transporter level is an important determinant of vesicle size.
authors.affiliation: Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Daniels
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Collins
authors.forename: Kaiyun
authors.initials: K
authors.lastname: Chen
authors.forename: Maria V
authors.initials: MV
authors.lastname: Gelfand
authors.forename: David E
authors.initials: DE
authors.lastname: Featherstone
authors.forename: Aaron
authors.initials: A
authors.lastname: DiAntonio
mesh_terms: D000818:Animals; D004330:Drosophila; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D009154:Mutation; D018408:Patch-Clamp Techniques; D013569:Synapses / Q000502:physiology / Q000648:ultrastructure; D013572:Synaptic Vesicles / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure; D050496:Vesicular Glutamate Transport Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D050496:Vesicular Glutamate Transport Proteins