Gephyrin-Lacking PV Synapses on Neocortical Pyramidal Neurons
Gephyrin has long been thought of as a master regulator for inhibitory synapses, acting as a scaffold to organize γ-aminobutyric acid type A receptors (GABA<sub>A</sub>Rs) at the post-synaptic density. Accordingly, gephyrin immunostaining has been used as an indicator of inhibitory synap...
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MDPI AG
2021-09-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/22/18/10032 |
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| author | Dika A. Kuljis Kristina D. Micheva Ajit Ray Waja Wegner Ryan Bowman Daniel V. Madison Katrin I. Willig Alison L. Barth |
| author_facet | Dika A. Kuljis Kristina D. Micheva Ajit Ray Waja Wegner Ryan Bowman Daniel V. Madison Katrin I. Willig Alison L. Barth |
| author_sort | Dika A. Kuljis |
| collection | DOAJ |
| description | Gephyrin has long been thought of as a master regulator for inhibitory synapses, acting as a scaffold to organize γ-aminobutyric acid type A receptors (GABA<sub>A</sub>Rs) at the post-synaptic density. Accordingly, gephyrin immunostaining has been used as an indicator of inhibitory synapses; despite this, the pan-synaptic localization of gephyrin to specific classes of inhibitory synapses has not been demonstrated. Genetically encoded fibronectin intrabodies generated with mRNA display (FingRs) against gephyrin (Gephyrin.FingR) reliably label endogenous gephyrin, and can be tagged with fluorophores for comprehensive synaptic quantitation and monitoring. Here we investigated input- and target-specific localization of gephyrin at a defined class of inhibitory synapse, using Gephyrin.FingR proteins tagged with EGFP in brain tissue from transgenic mice. Parvalbumin-expressing (PV) neuron presynaptic boutons labeled using Cre- dependent synaptophysin-tdTomato were aligned with postsynaptic Gephyrin.FingR puncta. We discovered that more than one-third of PV boutons adjacent to neocortical pyramidal (Pyr) cell somas lack postsynaptic gephyrin labeling. This finding was confirmed using correlative fluorescence and electron microscopy. Our findings suggest some inhibitory synapses may lack gephyrin. Gephyrin-lacking synapses may play an important role in dynamically regulating cell activity under different physiological conditions. |
| first_indexed | 2024-03-10T07:36:05Z |
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| id | doaj.art-c0f141e351d54fbd83f5aed9b9e283b4 |
| institution | Directory Open Access Journal |
| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-10T07:36:05Z |
| publishDate | 2021-09-01 |
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| series | International Journal of Molecular Sciences |
| spelling | doaj.art-c0f141e351d54fbd83f5aed9b9e283b42023-11-22T13:31:28ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672021-09-0122181003210.3390/ijms221810032Gephyrin-Lacking PV Synapses on Neocortical Pyramidal NeuronsDika A. Kuljis0Kristina D. Micheva1Ajit Ray2Waja Wegner3Ryan Bowman4Daniel V. Madison5Katrin I. Willig6Alison L. Barth7Center for the Neural Basis of Cognition, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USADepartment of Molecular and Cellular Physiology, Stanford University, Palo Alto, CA 94304, USACenter for the Neural Basis of Cognition, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USAOptical Nanoscopy in Neuroscience, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, 37075 Göttingen, GermanyCenter for the Neural Basis of Cognition, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USADepartment of Molecular and Cellular Physiology, Stanford University, Palo Alto, CA 94304, USAOptical Nanoscopy in Neuroscience, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, 37075 Göttingen, GermanyCenter for the Neural Basis of Cognition, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USAGephyrin has long been thought of as a master regulator for inhibitory synapses, acting as a scaffold to organize γ-aminobutyric acid type A receptors (GABA<sub>A</sub>Rs) at the post-synaptic density. Accordingly, gephyrin immunostaining has been used as an indicator of inhibitory synapses; despite this, the pan-synaptic localization of gephyrin to specific classes of inhibitory synapses has not been demonstrated. Genetically encoded fibronectin intrabodies generated with mRNA display (FingRs) against gephyrin (Gephyrin.FingR) reliably label endogenous gephyrin, and can be tagged with fluorophores for comprehensive synaptic quantitation and monitoring. Here we investigated input- and target-specific localization of gephyrin at a defined class of inhibitory synapse, using Gephyrin.FingR proteins tagged with EGFP in brain tissue from transgenic mice. Parvalbumin-expressing (PV) neuron presynaptic boutons labeled using Cre- dependent synaptophysin-tdTomato were aligned with postsynaptic Gephyrin.FingR puncta. We discovered that more than one-third of PV boutons adjacent to neocortical pyramidal (Pyr) cell somas lack postsynaptic gephyrin labeling. This finding was confirmed using correlative fluorescence and electron microscopy. Our findings suggest some inhibitory synapses may lack gephyrin. Gephyrin-lacking synapses may play an important role in dynamically regulating cell activity under different physiological conditions.https://www.mdpi.com/1422-0067/22/18/10032synapsesparvalbumingephyrinintrabodyGABA<sub>A</sub> receptorssynaptophysin |
| spellingShingle | Dika A. Kuljis Kristina D. Micheva Ajit Ray Waja Wegner Ryan Bowman Daniel V. Madison Katrin I. Willig Alison L. Barth Gephyrin-Lacking PV Synapses on Neocortical Pyramidal Neurons International Journal of Molecular Sciences synapses parvalbumin gephyrin intrabody GABA<sub>A</sub> receptors synaptophysin |
| title | Gephyrin-Lacking PV Synapses on Neocortical Pyramidal Neurons |
| title_full | Gephyrin-Lacking PV Synapses on Neocortical Pyramidal Neurons |
| title_fullStr | Gephyrin-Lacking PV Synapses on Neocortical Pyramidal Neurons |
| title_full_unstemmed | Gephyrin-Lacking PV Synapses on Neocortical Pyramidal Neurons |
| title_short | Gephyrin-Lacking PV Synapses on Neocortical Pyramidal Neurons |
| title_sort | gephyrin lacking pv synapses on neocortical pyramidal neurons |
| topic | synapses parvalbumin gephyrin intrabody GABA<sub>A</sub> receptors synaptophysin |
| url | https://www.mdpi.com/1422-0067/22/18/10032 |
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