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Updated: Jul 11, 2026

Preparation of Synaptoneurosomes from Mouse Cortex using a Discontinuous Percoll-Sucrose Density Gradient
Published on: September 17, 2011
The presynaptic particle web: ultrastructure, composition, dissolution, and reconstitution
G R Phillips1, J K Huang, Y Wang
1The Corinne Goldsmith Dickinson Center for Multiple Sclerosis, Department of Neurology and The Fishberg Research Center for Neurobiology, New York, NY 10029, USA.
Abstract:
We report the purification of a presynaptic "particle web" consisting of approximately 50 nm pyramidally shaped particles interconnected by approximately 100 nm spaced fibrils. This is the "presynaptic grid" described in early EM studies. It is completely soluble above pH 8, but reconstitutes after dialysis against pH 6. Interestingly, reconstituted particles orient and bind PSDs asymmetrically. Mass spectrometry of purified web components reveals major proteins involved in the exocytosis of synaptic vesicles and in membrane retrieval. Our data support the idea that the CNS synaptic junction is organized by transmembrane adhesion molecules interlinked in the synaptic cleft, connected via their intracytoplasmic domains to the presynaptic web on one side and to the postsynaptic density on the other. The CNS synaptic junction may therefore be conceptualized as a complicated macromolecular scaffold that isostatically bridges two closely aligned plasma membranes.
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