P2X-mediated AMPA receptor internalization and synaptic depression is controlled by two CaMKII phosphorylation sites on GluA1 in hippocampal neurons.
Plasticity at excitatory synapses can be induced either by synaptic release of glutamate or the release of gliotransmitters such as ATP. Recently, we showed that postsynaptic P2X2 receptors activated by ATP released from astrocytes downregulate synaptic AMPAR, providing a novel mechanism by which glial cells modulate synaptic activity. ATP- and lNMDA-induced depression in the CA1 region of the hippocampus are additive, suggesting distinct molecular pathways. AMPARs are homo-or hetero-tetramers composed of GluA1-A4. Here, we first show that P2X2-mediated AMPAR inhibition is dependent on the subunit composition of AMPAR. GluA3 homomers are insensitive and their presence in heteromers alters P2X-mediated inhibition. Using a mutational approach, we demonstrate that the two CaMKII phosphorylation sites S567 and S831 located in the cytoplasmic Loop1 and C-terminal tail of GluA1 subunits, respectively, are critical for P2X2-mediated AMPAR inhibition recorded from co-expressing Xenopus oocytes and removal of surface AMPAR at synapses of hippocampal neurons imaged by the super-resolution dSTORM technique. Finally, using phosphorylation site-specific antibodies, we show that P2X-induced depression in hippocampal slices produces a dephosphorylation of the GluA1 subunit at S567, contrary to NMDAR-mediated LTD. These findings indicate that GluA1 phosphorylation of S567 and S831 is critical for P2X2-mediated AMPAR internalization and ATP-driven synaptic depression.
Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France.|CNRS, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France.
Johan-Till
JT
Pougnet
Univ. de Bordeaux, Institut Interdisciplinaire des Neurosciences, UMR 5297, F-33000 Bordeaux, France.|CNRS, Institut Interdisciplinaire des Neurosciences, UMR 5297, F-33000 Bordeaux, France.
Benjamin
B
Compans
Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France.|CNRS, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France.
Audrey
A
Martinez
Univ. de Bordeaux, Institut Interdisciplinaire des Neurosciences, UMR 5297, F-33000 Bordeaux, France.|CNRS, Institut Interdisciplinaire des Neurosciences, UMR 5297, F-33000 Bordeaux, France.|Bordeaux Imaging Center, UMS 3420-US4 CNRS, INSERM, Université de Bordeaux, Bordeaux, France.
Daniel
D
Choquet
Univ. de Bordeaux, Institut Interdisciplinaire des Neurosciences, UMR 5297, F-33000 Bordeaux, France.|CNRS, Institut Interdisciplinaire des Neurosciences, UMR 5297, F-33000 Bordeaux, France.
Eric
E
Hosy
Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France.|CNRS, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France.
Eric
E
Boué-Grabot
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism*; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D006624:Hippocampus / Q000502:physiology*; D006801:Humans; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D018091:Receptors, AMPA / Q000378:metabolism*; D058476:Receptors, Purinergic P2X2 / Q000378:metabolism*; D013569:Synapses / Q000378:metabolism*; D014981:Xenopus
D000255:Adenosine Triphosphate; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D018091:Receptors, AMPA; D058476:Receptors, Purinergic P2X2