Neuron
Volume 68, Issue 4, 18 November 2010, Pages 710-723
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Article
Bassoon Speeds Vesicle Reloading at a Central Excitatory Synapse

https://doi.org/10.1016/j.neuron.2010.10.026Get rights and content
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Summary

Sustained rate-coded signals encode many types of sensory modalities. Some sensory synapses possess specialized ribbon structures, which tether vesicles, to enable high-frequency signaling. However, central synapses lack these structures, yet some can maintain signaling over a wide bandwidth. To analyze the underlying molecular mechanisms, we investigated the function of the active zone core component Bassoon in cerebellar mossy fiber to granule cell synapses. We show that short-term synaptic depression is enhanced in Bassoon knockout mice during sustained high-frequency trains but basal synaptic transmission is unaffected. Fluctuation and quantal analysis as well as quantification with constrained short-term plasticity models revealed that the vesicle reloading rate was halved in the absence of Bassoon. Thus, our data show that the cytomatrix protein Bassoon speeds the reloading of vesicles to release sites at a central excitatory synapse.

Highlights

► Generation of a transgenic mouse line that lacks Bassoon ► Normal basal transmission at mossy fiber to granule cell synapses in Bassoon mutants ► Enhanced synaptic depression within milliseconds during high-frequency transmission ► Halved rate of vesicle reloading at active zones in Bassoon knockout mice

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