Gephyrin Interacts with the K-Cl Cotransporter KCC2 to Regulate Its Surface Expression and Function in Cortical Neurons
| Autor: | Sabine Lévi, Marion Russeau, Oana Vigy, Martial Séveno, Philippe Marin, Florian Donneger, Pauline Weinzettl, Sana Al Awabdh, Marie Goutierre, Imane Moutkine, Jean Christophe Poncer |
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| Rok vydání: | 2021 |
| Předmět: |
Male
Scaffold protein Dendritic spine Neurotransmission Synaptic Transmission Rats Sprague-Dawley Glutamatergic medicine Animals GABAergic Neurons Research Articles Cerebral Cortex Neurons Neocortex Symporters Gephyrin biology Chemistry General Neuroscience Cell Membrane Membrane Proteins Receptors GABA-A Actin cytoskeleton Rats Cell biology medicine.anatomical_structure Synapses biology.protein GABAergic |
| Zdroj: | J Neurosci |
| ISSN: | 1529-2401 0270-6474 |
| Popis: | The K+-Cl–cotransporter KCC2, encoded by theSlc12a5gene, is a neuron-specific chloride extruder that tunes the strength and polarity of GABAAreceptor-mediated transmission. In addition to its canonical ion transport function, KCC2 also regulates spinogenesis and excitatory synaptic function through interaction with a variety of molecular partners. KCC2 is enriched in the vicinity of both glutamatergic and GABAergic synapses, the activity of which in turn regulates its membrane stability and function. KCC2 interaction with the submembrane actin cytoskeleton via 4.1N is known to control its anchoring near glutamatergic synapses on dendritic spines. However, the molecular determinants of KCC2 clustering near GABAergic synapses remain unknown. Here, we used proteomics to identify novel KCC2 interacting proteins in the adult rat neocortex. We identified both known and novel candidate KCC2 partners, including some involved in neuronal development and synaptic transmission. These include gephyrin, the main scaffolding molecule at GABAergic synapses. Gephyrin interaction with endogenous KCC2 was confirmed by immunoprecipitation from rat neocortical extracts. We showed that gephyrin stabilizes plasmalemmal KCC2 and promotes its clustering in hippocampal neurons, mostly but not exclusively near GABAergic synapses, thereby controlling KCC2-mediated chloride extrusion. This study identifies gephyrin as a novel KCC2 anchoring molecule that regulates its membrane expression and function in cortical neurons.SIGNIFICANCE STATEMENTFast synaptic inhibition in the brain is mediated by chloride-permeable GABAAreceptors (GABAARs) and therefore relies on transmembrane chloride gradients. In neurons, these gradients are primarily maintained by the K/Cl cotransporter KCC2. Therefore, understanding the mechanisms controlling KCC2 expression and function is crucial to understand its physiological regulation and rescue its function in the pathology. KCC2 function depends on its membrane expression and clustering, but the underlying mechanisms remain unknown. We describe the interaction between KCC2 and gephyrin, the main scaffolding protein at inhibitory synapses. We show that gephyrin controls plasmalemmal KCC2 clustering and that loss of gephyrin compromises KCC2 function. Our data suggest functional units comprising GABAARs, gephyrin, and KCC2 act to regulate synaptic GABA signaling. |
| Databáze: | OpenAIRE |
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