Molecular architecture of individual synaptic vesicles

ABSTRACT: Synaptic vesicles (SVs) perform neurotransmitter uptake inside the presynaptic neuron and their delivery to the synaptic cleft. The molecular composition of SVs was investigated, largely by proteomic analysis and fluorescent microscopy, and a model of an average SV was proposed. However, structural heterogeneity and molecular architecture of individual SVs are not yet well described. Here we used cryo-electron tomography (cryo-ET) to visualize morphological and molecular details of SVs isolated from native sources and inside synapses of cultured neurons. Surprisingly, a large fraction of the SV’s membrane did not show visible proteins. We describe several classes of small proteins on SVs' surface and long proteinaceous densities inside SVs. We identified large V-ATPases and determined their structure using subtomogram average (StA), and showed that it forms a complex with another membrane-embedded protein. Interestingly, V-ATPases were randomly distributed among the SVs irrespective of their sizes. We observed clathrin coats on a subpopulation of the SVs and partially assembled clathrin cages on isolated SVs and SVs inside cells. Finally, we describe non-vesicle-containing clathrin baskets, both from extracted SV preparations and within hippocampal neurons. Our analysis contributes to the understanding of the diversity of SVs and their molecular architecture.

INSTRUMENT(S): Orbitrap Fusion Lumos, Orbitrap Fusion

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Brain

SUBMITTER: Max Ruwolt  

LAB HEAD: Fan Liu

PROVIDER: PXD045356 | Pride | 2025-03-17

REPOSITORIES: Pride