title: Formation of an endophilin-Ca2+ channel complex is critical for clathrin-mediated synaptic vesicle endocytosis.
abstract: A tight balance between synaptic vesicle exocytosis and endocytosis is fundamental to maintaining synaptic structure and function. Calcium influx through voltage-gated Ca2+ channels is crucial in regulating synaptic vesicle exocytosis. However, much less is known about how Ca2+ regulates vesicle endocytosis or how the endocytic machinery becomes enriched at the nerve terminal. We report here a direct interaction between voltage-gated Ca2+ channels and endophilin, a key regulator of clathrin-mediated synaptic vesicle endocytosis. Formation of the endophlin-Ca2+ channel complex is Ca2+ dependent. The primary Ca2+ binding domain resides within endophilin and regulates both endophilin-Ca2+ channel and endophilin-dynamin complexes. Introduction into hippocampal neurons of a dominant-negative endophilin construct, which constitutively binds to Ca2+ channels, significantly reduces endocytosis-mediated uptake of FM 4-64 dye without abolishing exocytosis. These results suggest an important role for Ca2+ channels in coordinating synaptic vesicle recycling by directly coupling to both exocytotic and endocytic machineries.
authors.affiliation: Department of Pharmacology, University of Pennsylvania School of Medicine, 3620 Hamilton Walk, Philadelphia, PA 19104, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Chen
authors.forename: Lunbin
authors.initials: L
authors.lastname: Deng
authors.forename: Yuka
authors.initials: Y
authors.lastname: Maeno-Hikichi
authors.forename: Meizan
authors.initials: M
authors.lastname: Lai
authors.forename: Shaohua
authors.initials: S
authors.lastname: Chang
authors.forename: Gong
authors.initials: G
authors.lastname: Chen
authors.forename: Ji-fang
authors.initials: JF
authors.lastname: Zhang
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D002966:Clathrin / Q000378:metabolism*; D034281:Dynamins / Q000378:metabolism; D004594:Electrophysiology; D004705:Endocytosis / Q000502:physiology*; D006801:Humans; D046911:Macromolecular Substances; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D017729:Presynaptic Terminals / Q000378:metabolism; D017434:Protein Structure, Tertiary; D051381:Rats; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D009435:Synaptic Transmission; D013572:Synaptic Vesicles / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015220:Calcium Channels; D002352:Carrier Proteins; D002966:Clathrin; D046911:Macromolecular Substances; D011993:Recombinant Fusion Proteins; C107640:SH3GL2 protein, human; D034281:Dynamins; D002118:Calcium