Composition of isolated synaptic boutons reveals the amounts of vesicle trafficking proteins.
Level 5 - mechanism / opinion, no new human data
Bench research / in vitro quantitative proteomic and structural imaging study (Level 5).
PubMed 24876496 · doi:10.1126/science.1252884
What was done
The authors used an integrative structural and biochemical approach combining quantitative immunoblotting, mass spectrometry, electron microscopy, and super-resolution fluorescence microscopy on isolated synaptic boutons to quantify protein copy numbers, organelle metrics, and spatial localization, generating a 3D model of an average synapse containing approximately 300,000 proteins.
What was found
Copy numbers of proteins involved in the same step of synaptic vesicle recycling correlated closely. Across different trafficking steps, protein abundance varied over more than three orders of magnitude, ranging from about 150 copies for endosomal fusion proteins to more than 20,000 copies for exocytotic proteins.
Why it matters
This study provides an absolute quantitative blueprint and structural model of a synaptic bouton, defining the stoichiometry and dynamic range of the protein machinery driving neurotransmission.
Limits
The abstract does not state the biological origin of the tissue, number of replicates, or precise sample size. The generated 3D model represents an idealized average synapse, which may not capture functional heterogeneity across diverse neuronal subtypes or physiological states.
Cited by
- supports A single biological neuron in the human brain contains the entire human genome and traffics millions of proteins.