| Annotated protein: | Sodium/hydrogen exchanger. Gene symbol: SLC9A6. Taxonomy: Mus musculus (Mouse). Uniprot ID: B0QZV3 |
| antibody wiki: | |
| SynGO gene info: | SynGO data @ SLC9A6 |
| Ontology domain: | Biological Process |
| SynGO term: | regulation of postsynaptic membrane neurotransmitter receptor levels (GO:0099072) |
| Synapse type(s): | hippocampus, glutamatergic Schaffer collateral synapse (CA3->CA1) |
| Annotated paper: | Gao AYL, et al. "A Christianson syndrome-linked deletion mutation (Delta287ES288) in SLC9A6 impairs hippocampal neuronal plasticity" Neurobiol Dis. 2019 Oct;130:104490 PMID:31175985 |
| Figure(s): | Fig 4, 5 and S2 |
| Annotation description: | Fig 4A-C & TableS5: Endogenous WT NHE6 colocalizes strongly with the GluA1 subunit of AMPARs. However, this overlap is significantly attenuated in neurons expressing NHE6ΔES-mCh (SLC9A6 KO) and is accompanied by a significant decrease in GluA1 puncta at spines, indicating that the ΔES mutant deters the trafficking of GluA1 to excitatory synapses. Fig 4D-E: To investigate if the decrease in GluA1 levels in NHE6ΔES mutant is due to enhanced trafficking of GluA1 receptors to lysosomes, neurons were co-transfected with EGFP and influenza virus hemagglutinin (HA)-tagged constructs of NHE6 WT or ΔES to allow for double immunolabeling of the lysosomal marker LAMP1 and GluA1. Interestingly, in NHE6ΔES-HA-expressing cells, there was greater colocalization between LAMP1 and GluA1 compared to neurons expressing NHE6WT-HA. This finding implies that NHE6ΔES mutant preferentially targets GluA1 to lysosomal compartments rather than recycling endosomes. To investigate if NHE6ΔES mutant's role in AMPAR trafficking has an effect on glycine-mediated LTP, neurons were cotransfected with tdTomato (tdT) and N-terminal fused pH-sensitive superecliptic pHluorin (SEP)-GluA1 (sGluA1) alone, or with HA-tagged NHE6 WT or ΔES. Then they were subjected to a glycine-mediated chemical LTP (gly-ChemLTP) protocol to emulate NMDA receptor (NMDAR)-dependent LTP induction at Schaffer collateral-CA1 synapses in the hippocampus. Fig5A-C: 20 minutes following gly-ChemLTP induction in tdT control- and NHE6WT-HA-transfected neurons, a significant increase in the number of spines containing sGluA1 and upregulation of their puncta in the heads of these spines compared to unstimulated sister control cultures was observed. In contrast, gly-ChemLTP stimulation in NHE6ΔES-HA-expressing neurons did not show an increase in sGluA1 localization at spines or within the spine head compared to unstimulated controls. Fig S2A: To verify the NMDAR dependency of this protocol, additional sister NHE6WT-HA-expressing cultures were subjected to gly-ChemLTP supplemented with (RS)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid ((RS)-CPP), a potent NMDAR antagonist. As expected, these cells did not show an upregulation of sGluA1 puncta at spines or in spine heads. To summarise, NHE6ΔES mutant prevents GluA1 trafficking to spines and impairs the insertion of AMPARs at the cell surface following NMDAR-dependent LTP signifying a regulatory role in maintaining postsynaptic membrane AMPAR levels. |
| Evidence tracking, Biological System: | Cultured neurons |
| Evidence tracking, Protein Targeting: | Genetic transformation (eg; knockout, knockin, mutations) Antagonist / agonist Antibody (detection) |
| Evidence tracking, Experiment Assay: | Confocal Whole-cell patch clamp |
| Annotator(s): | Dnyanada Sahasrabudhe (ORCID:0000-0003-2916-7616) Guus Smit (ORCID:0000-0002-2286-1587) Matthijs Verhage (ORCID:0000-0002-2514-0216) |
| Lab: | Department of Functional Genomics, Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands |
| SynGO annotation ID: | 4101 |
| Dataset release (version): | 20231201 |
| View annotation as GO-CAM model: |  |