The fate of synaptic vesicle components upon fusion

Abstract

Neurotransmitter release relies on the fusion of synaptic vesicles with the plasma membrane of synaptic boutons, which is followed by the recycling of vesicle components and formation of new vesicles. It is not yet clear whether upon fusion the vesicles persist as multimolecular patches in the plasma membrane, or whether they segregate into individual components. Evidence supporting each of these two models has been suggested in recent years. Using diffraction-unlimited imaging (stimulated emission depletion, or STED) of native synaptic vesicle proteins, we have proposed that vesicle proteins remain in clusters on the neuronal surface. These clusters do not appear to intermix. We discuss here these findings in the context of previous studies on synaptic vesicle fusion, and we propose a recycling model which accounts for most of the recent findings on the post-fusion fate of synaptic vesicle components.

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Figures and Tables

Figure 1 Scheme representing two possible cases upon fusion. (A) newly exocytosed vesicle components (red) intermix with components resident on the plasma membrane (black), leading to the endocytosis of intermixed vesicle components. (B) newly exocytosed vesicle components (red) stay clustered and endocytosed vesicles keep their identity, although both newly exocytosed and membrane-resident components are internalized in separate vesicles.

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