Related Experiment Video
Updated: May 21, 2026
11:02
Presynaptically Silent Synapses Studied with Light Microscopy
Published on: January 4, 2010
Coordinated Pre- and Postsynaptic Protein Dynamics Underlie Rapid Sema4D-Induced Inhibitory Synapse Assembly
Zachary Pranske1, Suzanne Paradis2
1Department of Biology, Brandeis University, Waltham, Massachusetts 02454.
Eneuro
|May 19, 2026
Summary
Semaphorin 4D (Sema4D) rapidly synchronizes inhibitory synapse assembly in neurons. This study reveals a presynapse-first model where Sema4D coordinates protein dynamics for rapid GABAergic synapse formation.
Area of Science:
- Neuroscience
- Cell Biology
- Synaptic Plasticity
Background:
- Inhibitory synapse formation mechanisms are poorly understood due to asynchronous molecular events.
- Resolving the spatiotemporal dynamics of synaptogenesis has been challenging.
Purpose of the Study:
- To investigate the molecular events underlying inhibitory synapse assembly.
- To utilize Semaphorin 4D (Sema4D) to synchronize and observe GABAergic synapse formation in real-time.
- To elucidate the coordination of pre- and postsynaptic protein dynamics during synapse assembly.
Main Methods:
- Utilized Semaphorin 4D (Sema4D) to induce rapid, selective GABAergic synapse formation in cultured hippocampal neurons.
- Employed two-channel live imaging to observe pre- and postsynaptic protein dynamics.
- Analyzed the mobility and colocalization of key synaptic proteins like GAD65, gephyrin, and GABAARγ2 subunits.
Main Results:
- Sema4D treatment increased presynaptic GAD65-containing bouton mobility within 20 minutes.
- Postsynaptic gephyrin scaffolds were mobilized locally and proximity-dependently.
- GABAARγ2 subunits were recruited to gephyrin scaffolds prior to presynaptic alignment, suggesting scaffold priming.
- Observed new colocalization events indicating gephyrin or GABAAR clustering can nucleate postsynaptic assembly.
Conclusions:
- Sema4D coordinates pre- and postsynaptic protein dynamics with spatiotemporal precision to assemble inhibitory synapses within minutes.
- A presynapse-first model is supported, with postsynaptic scaffolds primed for receptor capture.
- Findings provide insights into inhibitory synapse assembly and potential implications for neurodevelopmental disorders.
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