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Synaptic vesicles interchange their membrane proteins with a large surface reservoir during recycling.

TitleSynaptic vesicles interchange their membrane proteins with a large surface reservoir during recycling.
Publication TypeJournal Article
Year of Publication2006
AuthorsFernandez-Alfonso T, Kwan R, Ryan TA
Date Published2006 Jul 20
KeywordsAnimals, Cell Membrane, Cells, Cultured, Endocytosis, Exocytosis, Membrane Proteins, Nerve Tissue Proteins, Rats, Rats, Sprague-Dawley, Surface Properties, Synaptic Vesicles, Vesicle-Associated Membrane Protein 2

During recycling of synaptic vesicles (SVs), the retrieval machinery faces the challenge of recapturing SV proteins in a timely and precise manner. The significant dilution factor that would result from equilibration of vesicle proteins with the much larger cell surface would make recapture by diffusional encounter with the endocytic retrieval machinery unlikely. If SV proteins exchanged with counterparts residing at steady state on the cell surface, the dilution problem would be largely avoided. In this scenario, during electrical activity, endocytosis would be driven by the concentration of a pre-existing pool of SVs residing on the axonal or synaptic surface rather than the heavily diluted postfusion vesicular pool. Using both live cell imaging of endogenous synaptotagmin Ia (sytIa) as well as pHluorin-tagged sytIa and VAMP-2, we show here that synaptic vesicle proteins interchange with a large pool on the cell axonal surface whose concentration is approximately 10-fold lower than that in SVs.

Alternate JournalNeuron
PubMed ID16846853
Grant ListR01 NS036942 / NS / NINDS NIH HHS / United States