| 1997 |
GluR7 (GRIK3) and its splice variant GluR7b are functional kainate receptor subunits with unique pharmacological properties; glutamate exhibits ~10-fold lower potency for GluR7-mediated currents compared to other non-NMDA receptor channels, establishing GluR7 as a low-sensitivity glutamate receptor. |
Electrophysiology (whole-cell patch-clamp) in Xenopus oocytes and HEK cells expressing recombinant receptors |
Neuron |
High |
9390526
|
| 1999 |
GluK3 (GluR7) coassembles with GluK1 (GluR5) and GluK2 (GluR6) to form heteromeric kainate receptors; coassembly of GluK3 with GluK2 markedly decreases agonist response amplitude, demonstrating a dominant-negative-like modulatory role in heteromeric assemblies. |
Electrophysiology with selective agonists (ATPA, I-will) and rectification analysis in Xenopus oocytes; pharmacological dissection of subunit coassembly |
The Journal of neuroscience |
High |
10493729
|
| 2001 |
The functional differences between GluK3 (GluR7) and GluK2 (GluR6) ion channel properties are localized to the extracellular loop domain L3; specific point mutations in GluK3 restore measurable currents in Xenopus oocytes, and the C-terminal half of L3 determines relative agonist efficacies (glutamate vs. kainate), while the S1 portion of the agonist-binding domain governs the high EC50 for glutamate. |
Domain-swap chimeras and point mutagenesis expressed in Xenopus oocytes; electrophysiology |
The Journal of neuroscience |
High |
11160421
|
| 2007 |
GluK3 (GluR7) is an essential subunit of presynaptic kainate autoreceptors at hippocampal mossy fiber synapses; GluK3 knockout mice display markedly reduced short- and long-term synaptic potentiation, and presynaptic KARs are GluK2/GluK3 heteromers localized within synapses with low glutamate sensitivity and likely Ca2+-permeable properties. |
GluR7 knockout mice, electrophysiology at mossy fiber synapses, coassembly demonstrated by coexpression in HEK cells, immunolocalization |
Proceedings of the National Academy of Sciences of the United States of America |
High |
17620617
|
| 2005 |
Alternative splicing of GluK3 (GluR7) at the C-terminal domain (GluR7a vs. GluR7b) regulates surface expression; GluR7a is highly expressed at the plasma membrane via a stretch of positively charged amino acids, whereas GluR7b is mostly retained in the endoplasmic reticulum. GluR7a promotes surface expression of ER-retained subunit splice variants when assembled into heteromeric KARs. |
Live-cell imaging, surface biotinylation, and trafficking assays in cultured hippocampal neurons from wild-type and KAR mutant mice; ER retention analysis |
The Journal of biological chemistry |
High |
15805114
|
| 2008 |
UBP302, UBP310, and UBP316 effectively block recombinant homomeric GluK3 receptors but are ineffective against homomeric GluK2 or heteromeric GluK2/GluK3 receptors; GYKI 53655 (AMPA receptor antagonist) blocks GluK3-containing receptors at high concentrations and decreases short-term plasticity at mossy fiber synapses. |
Fast-application electrophysiology in HEK293 cells expressing recombinant receptors; field recordings at hippocampal mossy fiber synapses |
Neuropharmacology |
High |
18761361
|
| 2010 |
Crystal structures of GluK3 amino-terminal domain (ATD) reveal it crystallizes as a dimer with a strikingly different dimer assembly at the R1 interface compared to GluK5, while the R2 domain dimer assembly is similar to other non-NMDA iGluRs; extensive intramolecular contacts between R1 and R2 restrict domain movement compared to NMDA receptors, consistent with GluK4/GluK5 requiring obligate coassembly with GluK1-GluK3. |
X-ray crystallography of ATD |
Journal of molecular biology |
High |
20951142
|
| 2011 |
X-ray crystal structure of the GluK3 ligand-binding domain (LBD) in complex with glutamate at 1.6 Å resolution reveals a conserved glutamate binding mode; GluK3 shows slightly lower domain closure around glutamate compared to other kainate receptors, and its LBD is less stabilized through interlobe interactions than GluK1, contributing to faster desensitization kinetics; key residues distinguishing GluK3 binding site are Thr520, Ala691, Asn722, Leu736, and Thr742. |
X-ray crystallography of LBD in complex with (S)-glutamate |
Journal of structural biology |
High |
21907808
|
| 2011 |
Endocytosis of GluK3b controls its polarized trafficking; a dileucine motif on the cytoplasmic C-terminal domain of GluK3b drives clathrin- and dynamin2-dependent internalization followed by degradation in heterologous cells, hippocampal neurons, and dentate granule cells; GluK3b is differentially endocytosed in dendrites compared to axons, providing a mechanism for polarized KAR distribution. |
Live-cell imaging, surface biotinylation, dominant-negative dynamin2 and clathrin constructs, organotypic slice cultures |
The Journal of neuroscience |
High |
21832194
|
| 2012 |
Zinc potentiates GluK3 currents at 10–100 μM by reducing desensitization; a specific zinc-binding site is formed at the base of the LBD dimer interface by a GluK3-specific residue Asp759 together with conserved His762 and Asp730 from the partner subunit; zinc stabilizes the labile GluK3 dimer interface to slow desensitization; GluK2/GluK3 tetramers are assembled as pairs of heterodimeric LBDs. |
Crystallography of LBD, site-directed mutagenesis, whole-cell electrophysiology (kinetic analysis and desensitization mutants) |
Neuron |
High |
23141068
|
| 2019 |
Cryo-EM structures of GluK3 in desensitized and resting/closed states reveal that antagonist-bound GluK3 traps a resting state with only two LBD domains in dimeric arrangement; N-linked glycans at the interface of GluK3 ATD and LBD mediate inter-domain interactions that modulate receptor gating properties, with mutational analysis identifying putative N-glycan interacting residues. |
Single-particle cryo-electron microscopy; site-directed mutagenesis; functional electrophysiology |
Scientific reports |
High |
31311973
|
| 2020 |
SEZ6 controls glycosylation and cell surface localization of GluK2/GluK3-containing kainate receptors; loss of SEZ6 reduces surface levels of GluK2/3 in primary neurons and reduces kainate-evoked currents in CA1 neurons; mechanistically, SEZ6 prevents HNK-1 glycan modification of GluK2/3, interacts with GluK2 through its ectodomain, and promotes post-ER transport of GluK2 in the secretory pathway. |
Co-immunoprecipitation, surface biotinylation, whole-cell electrophysiology in hippocampal slices, in vitro and in vivo SEZ6 KO models |
The EMBO journal |
High |
32567721
|
| 2020 |
Cryo-EM of full-length GluK3 in apo-state and in complex with agonist kainate or antagonist UBP301 reveals receptor transitions between desensitized and closed states; a 'non-classical' conformation of the neurotransmitter-binding domain is observed in the closed state, distinct from AMPA and other kainate receptors; molecular dynamics simulations show Asp759 influences LBD dimer stability, with lower dimer stability explaining faster desensitization and low agonist sensitivity of GluK3. |
Cryo-electron microscopy; molecular dynamics simulations |
International journal of biological macromolecules |
High |
32006583
|
| 2024 |
GluK3 KO mice in pure C57BL/6N background display anxiolytic-like behavior and reduced dopamine D2 receptor (D2R) expression in the striatum, with alteration in D2R-induced anxiety; biochemical studies confirm that GluK3 subunits do not coassemble with GluK4 or GluK5 subunits in mouse cortex. |
Genetic KO mice, behavioral assays, co-immunoprecipitation/biochemical fractionation |
Scientific reports |
Medium |
38402313
|
| 2024 |
Crystal structure of H523A-mutated GluK3 LBD dimer identifies binding sites for BPAM344 (positive allosteric modulator), zinc, sodium, and chloride ions at the dimer interface; molecular dynamics simulations implicate Asp761, Asp790, and Glu797 in zinc ion binding; cryo-EM of full-length GluK3 with glutamate and BPAM344 shows a dimer-of-dimers arrangement. |
X-ray crystallography; molecular dynamics simulations; cryo-electron microscopy; fluorescence-based functional assays |
The FEBS journal |
High |
38145505
|
| 2026 |
Neto1 and Neto2 auxiliary subunits differentially regulate GluK3 gating kinetics: both slow desensitization and relieve polyamine block, but Neto1 accelerates and Neto2 decelerates recovery from desensitization; Neto2 acts synergistically with zinc to produce profound facilitation of peak GluK3 currents; the D759G mutation at the LBD dimer interface zinc-binding site unmasks a secondary inhibitory zinc-binding site; cryo-EM confirms D759G promotes a more compact LBD arrangement. |
Whole-cell electrophysiology; site-directed mutagenesis (D759G); cryo-electron microscopy |
Communications biology |
High |
41680489
|
| 1994 |
Human GluK3 (EAA5) expressed in COS-1 cells binds kainate with a dissociation constant of ~2.72 nM, ~20-30 fold higher affinity than rat GluR7; a Ser310Ala variation at position 310 in the extracellular N-terminal region was identified, originally attributed to RNA editing but later reclassified as a genomic polymorphism. |
Ligand binding studies with transfected COS-1 cell membranes; cDNA cloning and sequencing |
Receptors & channels |
Medium |
7719709
|
| 2000 |
The human GluK3 Ser310Ala variant is a genomic single nucleotide polymorphism (T/G at position 928), not RNA editing; whole-cell patch-clamp in HEK-293 cells expressing the two isoforms detected no differences in receptor activation or desensitization, indicating the polymorphism does not affect basic channel function. |
Patch-clamp electrophysiology in HEK-293 cells; allele-specific expression analysis in human brain tissue |
The Journal of neuroscience |
Medium |
11124978
|