title: Clathrin/AP-2 mediate synaptic vesicle reformation from endosome-like vacuoles but are not essential for membrane retrieval at central synapses.
abstract: Neurotransmission depends on presynaptic membrane retrieval and local reformation of synaptic vesicles (SVs) at nerve terminals. The mechanisms involved in these processes are highly controversial with evidence being presented for SV membranes being retrieved exclusively via clathrin-mediated endocytosis (CME) from the plasma membrane or via ultrafast endocytosis independent of clathrin. Here we show that clathrin and its major adaptor protein 2 (AP-2) in addition to the plasma membrane operate at internal endosome-like vacuoles to regenerate SVs but are not essential for membrane retrieval. Depletion of clathrin or conditional knockout of AP-2 result in defects in SV reformation and an accumulation of endosome-like vacuoles generated by clathrin-independent endocytosis (CIE) via dynamin 1/3 and endophilin. These results together with theoretical modeling provide a conceptual framework for how synapses capitalize on clathrin-independent membrane retrieval and clathrin/AP-2-mediated SV reformation from endosome-like vacuoles to maintain excitability over a broad range of stimulation frequencies.
authors.affiliation: Leibniz Institut für Molekulare Pharmakologie (FMP) & Freie Universität Berlin, Robert-Roessle-Straße 10, 13125 Berlin, Germany; Charite Universitätsmedizin, NeuroCure Cluster of Excellence, Virchowweg 6, 10117 Berlin, Germany.
authors.forename: Natalia L
authors.initials: NL
authors.lastname: Kononenko
authors.affiliation: Leibniz Institut für Molekulare Pharmakologie (FMP) & Freie Universität Berlin, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Dmytro
authors.initials: D
authors.lastname: Puchkov
authors.affiliation: Leibniz Institut für Molekulare Pharmakologie (FMP) & Freie Universität Berlin, Robert-Roessle-Straße 10, 13125 Berlin, Germany; Charite Universitätsmedizin, NeuroCure Cluster of Excellence, Virchowweg 6, 10117 Berlin, Germany.
authors.forename: Gala A
authors.initials: GA
authors.lastname: Classen
authors.affiliation: Leibniz Institut für Molekulare Pharmakologie (FMP) & Freie Universität Berlin, Robert-Roessle-Straße 10, 13125 Berlin, Germany; Charite Universitätsmedizin, NeuroCure Cluster of Excellence, Virchowweg 6, 10117 Berlin, Germany.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Walter
authors.affiliation: Leibniz Institut für Molekulare Pharmakologie (FMP) & Freie Universität Berlin, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Arndt
authors.initials: A
authors.lastname: Pechstein
authors.affiliation: Leibniz Institut für Molekulare Pharmakologie (FMP) & Freie Universität Berlin, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Linda
authors.initials: L
authors.lastname: Sawade
authors.affiliation: Leibniz Institut für Molekulare Pharmakologie (FMP) & Freie Universität Berlin, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Natalie
authors.initials: N
authors.lastname: Kaempf
authors.affiliation: Charite Universitätsmedizin, NeuroCure Cluster of Excellence, Virchowweg 6, 10117 Berlin, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Trimbuch
authors.affiliation: Leibniz Institut für Molekulare Pharmakologie (FMP) & Freie Universität Berlin, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Dorothea
authors.initials: D
authors.lastname: Lorenz
authors.affiliation: Charite Universitätsmedizin, NeuroCure Cluster of Excellence, Virchowweg 6, 10117 Berlin, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Rosenmund
authors.affiliation: Leibniz Institut für Molekulare Pharmakologie (FMP) & Freie Universität Berlin, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Tanja
authors.initials: T
authors.lastname: Maritzen
authors.affiliation: Leibniz Institut für Molekulare Pharmakologie (FMP) & Freie Universität Berlin, Robert-Roessle-Straße 10, 13125 Berlin, Germany; Charite Universitätsmedizin, NeuroCure Cluster of Excellence, Virchowweg 6, 10117 Berlin, Germany. Electronic address: haucke@fmp-berlin.de.
authors.forename: Volker
authors.initials: V
authors.lastname: Haucke
mesh_terms: D033962:Adaptor Protein Complex 2 / Q000235:genetics / Q000502:physiology*; D000818:Animals; D002966:Clathrin / Q000235:genetics / Q000502:physiology*; D003034:Coated Pits, Cell-Membrane / Q000502:physiology* / Q000648:ultrastructure; D034281:Dynamins / Q000378:metabolism; D004705:Endocytosis; D011992:Endosomes / Q000502:physiology / Q000648:ultrastructure; D006624:Hippocampus / Q000502:physiology* / Q000648:ultrastructure; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008962:Models, Theoretical; D009474:Neurons / Q000502:physiology / Q000648:ultrastructure; D051381:Rats; D013569:Synapses / Q000502:physiology* / Q000648:ultrastructure; D013572:Synaptic Vesicles / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D033962:Adaptor Protein Complex 2; D002966:Clathrin; D034281:Dynamins