title: Synaptic Vesicle Endocytosis Occurs on Multiple Timescales and Is Mediated by Formin-Dependent Actin Assembly.
abstract: Neurotransmission is based on the exocytic fusion of synaptic vesicles (SVs) followed by endocytic membrane retrieval and the reformation of SVs. Recent data suggest that at physiological temperature SVs are internalized via clathrin-independent ultrafast endocytosis (UFE) within hundreds of milliseconds, while other studies have postulated a key role for clathrin-mediated endocytosis (CME) of SV proteins on a timescale of seconds to tens of seconds. Here we demonstrate using cultured hippocampal neurons as a model that at physiological temperature SV endocytosis occurs on several timescales from less than a second to several seconds, yet, is largely independent of clathrin. Clathrin-independent endocytosis (CIE) of SV membranes is mediated by actin-nucleating formins such as mDia1, which are required for the formation of presynaptic endosome-like vacuoles from which SVs reform. Our results resolve previous discrepancies in the field and suggest that SV membranes are predominantly retrieved via CIE mediated by formin-dependent actin assembly.
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany.
authors.forename: Tolga
authors.initials: T
authors.lastname: Soykan
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany.
authors.forename: Natalie
authors.initials: N
authors.lastname: Kaempf
authors.affiliation: Doshisha University, Graduate School of Brain Science, Kyoto 610-0394, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sakaba
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany.
authors.forename: Dennis
authors.initials: D
authors.lastname: Vollweiter
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany; Freie Universität Berlin, Faculty of Biology, Chemistry and Pharmacy, 14195 Berlin, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Goerdeler
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany.
authors.forename: Dmytro
authors.initials: D
authors.lastname: Puchkov
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, 10117 Berlin, Germany; CECAD Research Center, University of Cologne, 50931 Cologne, Germany.
authors.forename: Natalia L
authors.initials: NL
authors.lastname: Kononenko
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany; Freie Universität Berlin, Faculty of Biology, Chemistry and Pharmacy, 14195 Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, 10117 Berlin, Germany. Electronic address: haucke@fmp-berlin.de.
authors.forename: Volker
authors.initials: V
authors.lastname: Haucke
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D002966:Clathrin / Q000378:metabolism; D004705:Endocytosis / Q000502:physiology*; D011992:Endosomes / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism; D008822:Mice, Transgenic; D009435:Synaptic Transmission / Q000502:physiology; D013572:Synaptic Vesicles / Q000378:metabolism*
chemical_list: D000199:Actins; D002352:Carrier Proteins; D002966:Clathrin
keywords: actin; calyx of Held; clathrin; endocytosis; formin; hippocampus; kinetics; neurotransmission; recycling; synaptic vesicles