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Published on: September 3, 2014
Differential roles of postsynaptic density-93 isoforms in regulating synaptic transmission
Juliane M Krüger1, Plinio D Favaro, Mingna Liu
1European Neuroscience Institute, 37077 Göttingen, Germany, Göttingen Graduate School for Neurosciences and Molecular Biosciences, 37077 Göttingen, Germany, Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02319, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany, International Max Planck Research School for Neuroscience, 37077 Göttingen, Germany, Bioanalytics, Department of Clinical Chemistry, 37075 Göttingen, Germany, and Department of Neuroscience, University of Pittsburgh, Pennsylvania 15260.
The scaffolding protein PSD-93, with its six isoforms, is crucial for maintaining excitatory synaptic transmission strength. Different PSD-93 isoforms fine-tune signaling to meet varying synaptic demands during development.
Area of Science:
- Neuroscience
- Molecular Biology
- Synaptic Plasticity
Background:
- Discs large (DLG)-membrane-associated guanylate kinase (MAGUK) proteins scaffold signaling pathways in glutamatergic synapses.
- Postsynaptic density-93 (PSD-93) is a highly variable MAGUK with six N-terminal isoforms, leading to uncertainty about its specific synaptic roles.
Purpose of the Study:
- To elucidate the precise synaptic function of PSD-93 by characterizing its six N-terminal isoforms.
- To investigate how PSD-93 isoforms regulate excitatory synaptic transmission strength at different developmental stages.
Main Methods:
- Quantification of all six PSD-93 isoforms in mouse hippocampus.
- Individual examination of PSD-93 isoforms in hippocampal synapses using molecular manipulations (overexpression, knockdown, knockout).
- Biochemical assays and slice electrophysiology in rat and mouse models.
Main Results:
- PSD-93 is essential for maintaining excitatory synaptic transmission strength across different developmental synaptic states.
- The six PSD-93 isoforms differentially regulate synaptic strength, impacting α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor synapses (active and inactive).
- Activity-dependent modulations of synaptic transmission are influenced by specific PSD-93 isoforms.
Conclusions:
- Alternative combinations of PSD-93 isoforms and DLG-MAGUK paralogs provide a flexible mechanism for fine-tuning synaptic signaling scaffolds.
- These adaptable scaffolds adjust to specific synaptic requirements, thereby regulating synaptic transmission efficacy.
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