Formation of an endophilin-Ca2+ channel complex is critical for clathrin-mediated synaptic vesicle endocytosis.
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.
Chen
Yuan
Y
Department of Pharmacology, University of Pennsylvania School of Medicine, 3620 Hamilton Walk, Philadelphia, PA 19104, USA.
Deng
Lunbin
L
Maeno-Hikichi
Yuka
Y
Lai
Meizan
M
Chang
Shaohua
S
Chen
Gong
G
Zhang
Ji-fang
JF
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
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