Abstract
Synaptic vesicle recycling is essential for maintaining efficient synaptic transmission. Detailed dissection of single-vesicle recycling still remains a major challenge. We have developed a fluorescent pH reporter that permits us to follow the fate of individual vesicles at hippocampal synapses after exocytosis. Here we show that, during low-frequency stimulation, single-vesicle fusion leads to two distinct vesicle internalizations, instead of one, as in general perception: one by a fast endocytosis pathway (∼3 s), the other by a slow endocytosis pathway (after 10 s). The exocytosed vesicular proteins are preferentially recaptured in both pathways. RNAi knockdown of clathrin inhibits both pathways. As stimulation frequency increases, the number of endocytosed vesicles begins to match antecedent exocytosis. Meanwhile, the slow endocytosis is accelerated and becomes the predominant pathway. These results reveal that two pathways of endocytosis are orchestrated during neuronal activity, establishing a highly efficient endocytosis at central synapses.
Original language | English (US) |
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Pages (from-to) | 397-411 |
Number of pages | 15 |
Journal | Neuron |
Volume | 61 |
Issue number | 3 |
DOIs | |
State | Published - Feb 12 2009 |
Funding
We thank Dr. Charles F. Stevens for providing laboratory space and experimental instruments to carry out this study and for his insightful advice throughout the work. We thank Dr. Wolfhard Almers for critical reading of the manuscript and insightful comments. The work was supported in part by the Howard Hughes Medical Institute and in part by NIH (S.F.H).
Keywords
- CELLBIO
- MOLNEURO
ASJC Scopus subject areas
- General Neuroscience