The Well-Networked Synapse

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Science  26 Oct 2001:
Vol. 294, Issue 5543, pp. 749
DOI: 10.1126/science.294.5543.749b

Neuronal function relies on precisely apposed synaptic contacts between the upstream cell, which releases transmitters via synaptic vesicle exocytosis, and the downstream cell, which harbors the receptors occupied by the transmitters. Recent studies have begun to lay a biochemical foundation for the interpretation of classical electron microscopic observations of networks of electron-dense material on the cytoplasmic surface of the presynaptic membrane. Phillips et al. describe the isolation of a “presynaptic particle web” from mammalian brain; this web consists of 50-nanometer particles within a mesh of thin (about 10-nm) fibrils, which is qualitatively similar to the well-studied, spectrin-based cytoskeletal structure of the erythrocyte and also to the “active zone material” at the neuromuscular junction. Proteins were identified as loosely or tightly associated, and these assignments were consistent with their known or suspected functional roles. The interaction of this web with the presynaptic cytomatrix, the substructure that is thought to help guide and mobilize synaptic vesicles (as Koushika et al. show for the protein Rim), is reminiscent of the fibrillar basket that guides export cargoes to and through the nuclear pore.—GJC

Neuron32, 63 (2001); Nature Neurosci.4, 997 (2001).

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