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Quantitative analysis of the native presynaptic cytomatrix by cryoelectron tomography.

Fernández-Busnadiego R, Zuber B, Maurer UE, Cyrklaff M, Baumeister W, Lucic V - J. Cell Biol. (2010)

Bottom Line: The presynaptic terminal contains a complex network of filaments whose precise organization and functions are not yet understood.Docked synaptic vesicles did not make membrane to membrane contact with the active zone but were instead linked to it by tethers of different length.The formation of short tethers was inhibited by tetanus toxin, indicating that it depends on soluble N-ethyl-maleimide sensitive fusion protein attachment protein receptor complex assembly.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany.

ABSTRACT
The presynaptic terminal contains a complex network of filaments whose precise organization and functions are not yet understood. The cryoelectron tomography experiments reported in this study indicate that these structures play a prominent role in synaptic vesicle release. Docked synaptic vesicles did not make membrane to membrane contact with the active zone but were instead linked to it by tethers of different length. Our observations are consistent with an exocytosis model in which vesicles are first anchored by long (>5 nm) tethers that give way to multiple short tethers once vesicles enter the readily releasable pool. The formation of short tethers was inhibited by tetanus toxin, indicating that it depends on soluble N-ethyl-maleimide sensitive fusion protein attachment protein receptor complex assembly. Vesicles were extensively interlinked via a set of connectors that underwent profound rearrangements upon synaptic stimulation and okadaic acid treatment, suggesting a role of these connectors in synaptic vesicle mobilization and neurotransmitter release.

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Images of synaptic vesicle tethers. (A–D) Short (A and B; <5 nm) and long (C and D; >5 nm) synaptic vesicle tethers (white arrowheads) are shown. SC, synaptic cleft. Two consecutive 2.7-nm-thick tomographic slices are shown for each case. Bar, 50 nm.
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fig5: Images of synaptic vesicle tethers. (A–D) Short (A and B; <5 nm) and long (C and D; >5 nm) synaptic vesicle tethers (white arrowheads) are shown. SC, synaptic cleft. Two consecutive 2.7-nm-thick tomographic slices are shown for each case. Bar, 50 nm.

Mentions: Filaments of variable length (Fig. 5 and Fig. 6 C) tethered the majority of the synaptic vesicles in the proximal zone to the AZ in untreated, HTS, TeTx-treated synaptosomes, and organotypic slices, whereas tethering was significantly reduced for KCl and OA treatments (P < 0.001 by χ2 test; Fig. 6 A). All tethered vesicles were located in the proximal zone, and only rarely was there a direct contact between vesicle and cell membranes. Compared with untreated synapses, there was a significantly lower number of tethers per vesicle in the HTS-treated case (P < 0.001 by K-W test; Fig. 6 B), which is largely the result of the low number of vesicles having more than two tethers (P < 0.01 by χ2 test; Fig. S2 C).


Quantitative analysis of the native presynaptic cytomatrix by cryoelectron tomography.

Fernández-Busnadiego R, Zuber B, Maurer UE, Cyrklaff M, Baumeister W, Lucic V - J. Cell Biol. (2010)

Images of synaptic vesicle tethers. (A–D) Short (A and B; <5 nm) and long (C and D; >5 nm) synaptic vesicle tethers (white arrowheads) are shown. SC, synaptic cleft. Two consecutive 2.7-nm-thick tomographic slices are shown for each case. Bar, 50 nm.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2812849&req=5

fig5: Images of synaptic vesicle tethers. (A–D) Short (A and B; <5 nm) and long (C and D; >5 nm) synaptic vesicle tethers (white arrowheads) are shown. SC, synaptic cleft. Two consecutive 2.7-nm-thick tomographic slices are shown for each case. Bar, 50 nm.
Mentions: Filaments of variable length (Fig. 5 and Fig. 6 C) tethered the majority of the synaptic vesicles in the proximal zone to the AZ in untreated, HTS, TeTx-treated synaptosomes, and organotypic slices, whereas tethering was significantly reduced for KCl and OA treatments (P < 0.001 by χ2 test; Fig. 6 A). All tethered vesicles were located in the proximal zone, and only rarely was there a direct contact between vesicle and cell membranes. Compared with untreated synapses, there was a significantly lower number of tethers per vesicle in the HTS-treated case (P < 0.001 by K-W test; Fig. 6 B), which is largely the result of the low number of vesicles having more than two tethers (P < 0.01 by χ2 test; Fig. S2 C).

Bottom Line: The presynaptic terminal contains a complex network of filaments whose precise organization and functions are not yet understood.Docked synaptic vesicles did not make membrane to membrane contact with the active zone but were instead linked to it by tethers of different length.The formation of short tethers was inhibited by tetanus toxin, indicating that it depends on soluble N-ethyl-maleimide sensitive fusion protein attachment protein receptor complex assembly.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany.

ABSTRACT
The presynaptic terminal contains a complex network of filaments whose precise organization and functions are not yet understood. The cryoelectron tomography experiments reported in this study indicate that these structures play a prominent role in synaptic vesicle release. Docked synaptic vesicles did not make membrane to membrane contact with the active zone but were instead linked to it by tethers of different length. Our observations are consistent with an exocytosis model in which vesicles are first anchored by long (>5 nm) tethers that give way to multiple short tethers once vesicles enter the readily releasable pool. The formation of short tethers was inhibited by tetanus toxin, indicating that it depends on soluble N-ethyl-maleimide sensitive fusion protein attachment protein receptor complex assembly. Vesicles were extensively interlinked via a set of connectors that underwent profound rearrangements upon synaptic stimulation and okadaic acid treatment, suggesting a role of these connectors in synaptic vesicle mobilization and neurotransmitter release.

Show MeSH
Related in: MedlinePlus