{"gene":"GRIN1","run_date":"2026-06-10T01:55:21","timeline":{"discoveries":[{"year":1994,"finding":"NMDAR1 (GluN1) protein localizes predominantly to postsynaptic densities in neurons of the hippocampus, cerebral cortex, and cerebellar cortex, as determined by ultrastructural immunolocalization. The major staining was in postsynaptic densities apposed by unstained presynaptic terminals, indicating GluN1 is a postsynaptic component of NMDA receptor complexes.","method":"Light and electron microscope immunocytochemistry with selective anti-peptide antibody on rat nervous system sections","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct subcellular localization by electron microscopy with functional context, replicated across multiple brain regions; foundational localization paper widely confirmed","pmids":["8301357"],"is_preprint":false},{"year":1993,"finding":"In PC12 cells, NMDAR1 mRNA is present but little or no NMDAR1 protein is detectable endogenously, and no functional NMDA-gated ion channels are observed; however, transfection with an NMDAR1 expression vector produces detectable protein. This indicates post-transcriptional regulation controls NMDAR1 protein expression.","method":"Northern hybridization, PCR, monoclonal antibody immunoblot, calcium imaging, and patch-clamp recording in PC12 cells; transfection rescue experiment","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — multiple orthogonal methods (Northern blot, immunoblot, electrophysiology, calcium imaging, transfection rescue) in a single rigorous study establishing post-transcriptional control","pmids":["8226739"],"is_preprint":false},{"year":1996,"finding":"Estradiol treatment in ovariectomized rats increases NMDAR1 subunit protein immunofluorescence in CA1 pyramidal cell somata and dendrites without changing NMDAR1 mRNA levels, indicating estradiol modulates NMDA receptor function via post-transcriptional regulation of the GluN1 subunit protein.","method":"Confocal laser scanning microscopy for immunofluorescence quantification of NMDAR1 protein; in situ hybridization for NMDAR1 mRNA in rat hippocampal regions","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — two orthogonal methods (protein immunofluorescence quantification + mRNA in situ hybridization) with clear dissociation of protein vs mRNA regulation; single lab but rigorous experimental design","pmids":["8824322"],"is_preprint":false},{"year":1997,"finding":"After perforant path transection, NMDAR1 mRNA increases throughout the full dendritic extent of dentate gyrus granule cells (including non-denervated segments), whereas increased NMDAR1 protein is restricted to denervated dendritic segments. This demonstrates that NMDAR1 mRNA is transported into dendrites and that local protein synthesis is regulated independently of mRNA transport in response to synaptic reorganization.","method":"Quantitative immunofluorescence and in situ hybridization in rat hippocampus at 2, 5, and 9 days post-lesion","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — two orthogonal methods (immunofluorescence protein quantification + in situ hybridization mRNA quantification) with clear dissociation at subcellular compartment level","pmids":["9045729"],"is_preprint":false},{"year":1998,"finding":"Cell-type-specific transcription of the NMDAR1 gene is controlled by the neuron-restrictive silencer element (NRSE/NRSF) and by single-stranded DNA-binding proteins (SBPs) interacting with a GC-rich/Sp1-containing proximal promoter region. The SBPC2 complex (enriched in neurons) correlates with higher promoter activity; NGF treatment shifts the ratio from SBPC1 to SBPC2 in PC12 cells, suggesting a mechanism for NGF-regulated NMDAR1 transcription.","method":"Deletion analysis of NMDAR1 promoter in C6, HeLa, and PC12 cells; EMSA with nuclear proteins; UV cross-linking; competition experiments; cotransfection with single-stranded DNA","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — multiple orthogonal methods (promoter deletion, EMSA, UV cross-linking, cotransfection) in a single study, single lab","pmids":["9422773"],"is_preprint":false},{"year":1998,"finding":"In nNOS-positive neurons of the neostriatum, neocortex, and hippocampus, the NMDAR1 subunit is present but specifically lacks the C1 splice cassette and preferentially contains the C2' terminus (generated when the C2 segment is absent), revealing that nNOS neurons express a distinct NMDAR1 isoform profile compared to surrounding neurons.","method":"Dual-label immunofluorescence with confocal microscopy using antibodies to nNOS and NMDAR1 cassettes (N1, C1, C2) in rat forebrain","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal dual-label immunofluorescence with multiple antibodies recognizing distinct splice cassettes; single lab, single method type but uses multiple probes","pmids":["9464997"],"is_preprint":false},{"year":2013,"finding":"The σ-1 receptor (Sig1R) binds directly and specifically to the GluN1 subunit within GluN1/GluN2A NMDA receptor heterotetramers, but not to GluN2A. This was shown by AFM imaging of subunit arrangement angles, co-isolation experiments, and in situ proximity ligation assays in intact cells. The Sig1R C-terminus faces extracellularly.","method":"Atomic force microscopy (AFM) imaging of receptor complexes; co-immunoprecipitation of Sig1R with GluN1 but not GluN2A; proximity ligation assay in intact cells","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (AFM imaging with angle analysis, reciprocal co-IP, in situ PLA in intact cells) in a single rigorous study","pmids":["24227730"],"is_preprint":false},{"year":2012,"finding":"Functional GluN1/GluN2A NMDA receptors adopt an alternating 1/2/1/2 subunit arrangement (like subunits diagonal to one another). In this arrangement, GluN1 subunits occupy a 'proximal' position closer to the central pore axis than GluN2 subunits. Immature (intracellular) and mature (plasma-membrane-inserted) receptor pools can adopt different subunit arrangements.","method":"Electrophysiology (disulfide cross-linking between subunits combined with functional recording) and structural analysis based on AMPA receptor crystal structure homology","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — electrophysiology combined with disulfide cross-linking and structural analysis; multiple approaches converging on same conclusion in a single study","pmids":["22493736"],"is_preprint":false},{"year":2013,"finding":"The GluN1 N-terminal domain (NTD) is neither static nor functionally silent. Perturbing GluN1 NTD conformation affects receptor gating and pharmacological properties. GluN1 NTD undergoes hinge-bending, twisting, and untwisting motions forming new intra- and intersubunit contacts, and acts in trans with GluN2 NTD to influence glutamate binding (but not GluN1 glycine binding).","method":"Single-molecule FRET, mutagenesis, electrophysiology of recombinant NMDARs; conformational perturbation of GluN1 NTD with designed mutations","journal":"Nature structural & molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — smFRET structural dynamics combined with mutagenesis and electrophysiology; multiple orthogonal methods; single lab","pmids":["23454977"],"is_preprint":false},{"year":2013,"finding":"Crystal structures of the GluN1 ligand-binding domain (LBD) in the apo state reveal an open-cleft conformation. Computed free energy landscapes show GluN1 apo-state LBDs sample closed-cleft conformations via conformational selection (rather than induced-fit) for glycine binding, with a spectrum of hinge bending, rocking, twisting, and sweeping motions distinct from GluN2A and GluN3A LBDs.","method":"X-ray crystallography of GluN1 LBD; computational conformational free energy landscapes; principal component analysis","journal":"Structure","confidence":"High","confidence_rationale":"Tier 1 / Moderate — crystal structure combined with computational analysis; rigorous structural and dynamic characterization; single lab","pmids":["23972471"],"is_preprint":false},{"year":2013,"finding":"Crystal structure of the GluN1 ligand-binding domain in complex with the competitive antagonist TK40 reveals that TK40 binds to the orthosteric glycine-binding site of GluN1 with an imino acetamido group acting as an α-amino acid bioisostere. Schild analysis confirmed competitive antagonism with Kb of 21–63 nM at GluN1/GluN2A-D, with >100-fold selectivity over GluN3-containing receptors.","method":"X-ray crystallography of GluN1 LBD–TK40 complex; Schild analysis; radioligand binding on rat brain membranes and purified GluN1 LBD; virtual screening","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure, functional pharmacological characterization, and radioligand binding; multiple orthogonal methods; clear mechanistic insight","pmids":["24072709"],"is_preprint":false},{"year":2012,"finding":"The GluN1 exon 5-encoded N1 cassette in the amino-terminal domain is a key determinant of GluN1/GluN2D receptor function. GluN1-1b (exon 5-containing) receptors deactivate ~3-fold faster and have ~2-fold higher open probability than GluN1-1a receptors. Residue Lys211 in GluN1-1b is identified as a critical determinant of exon 5 control of deactivation and glutamate potency.","method":"Whole-cell and single-channel electrophysiology of recombinant GluN1/GluN2D receptors with GluN1 splice variants; site-directed mutagenesis; kinetic modeling","journal":"The Journal of physiology","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstituted recombinant receptors, mutagenesis, multiple electrophysiological readouts, and kinetic modeling in a single rigorous study","pmids":["22641781"],"is_preprint":false},{"year":2011,"finding":"Intrasubunit disulfide bonds that constrain the M3-S2 linker in either the GluN1 or GluN2A subunit equally impair NMDA receptor pore opening, demonstrating that conformational freedom of the LBD-TMD linkers in both subunits is required and that the pore-opening mechanism involves tightly coupled intrasubunit dynamics at LBD-TMD linkers across all four subunits.","method":"Disulfide bond engineering (intrasubunit bonds between M3-S2 and S2-M4 linkers) in GluN1 or GluN2A; whole-cell and single-channel electrophysiology","journal":"The Journal of general physiology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — engineered disulfide constraints with electrophysiological validation; clean gain-of-constraint approach with single-channel analysis; single lab","pmids":["21746848"],"is_preprint":false},{"year":2015,"finding":"The GluN1 ligand-binding domain exists in multiple conformations even when glycine is bound, transitioning reversibly among states corresponding to different cleft widths on long timescales (much longer than channel opening). The LBD proceeds primarily from one adjacent smFRET state to the next, consistent with a sequential cleft-opening/closing mechanism.","method":"Single-molecule FRET on purified GluN1 LBD with glycine bound; step-transition and state-identification algorithm; denaturant shift experiments","journal":"Biophysical journal","confidence":"High","confidence_rationale":"Tier 1 / Moderate — single-molecule FRET with reversibility confirmation and model-free state analysis; single lab but multiple orthogonal validations within study","pmids":["26153703"],"is_preprint":false},{"year":2014,"finding":"Concurrent stimulation of D1 dopamine receptors (D1R) and NMDA receptors drives formation of D1R/GluN1 complexes. Preventing D1R/GluN1 association with a cell-permeable TAT-GluN1C1 peptide leaves individual D1R and NMDAR signaling intact but blocks D1R-mediated facilitation of NMDAR calcium influx and ERK activation. D1R/GluN1 complexes control D1R-dependent enhancement of NMDAR currents and LTP in D1R-MSN, and are required for cocaine behavioral sensitization.","method":"Co-immunoprecipitation of endogenous D1R and GluN1; cell-permeable blocking peptide (TAT-GluN1C1); calcium imaging; ERK phosphorylation assay; whole-cell electrophysiology in striatal slices; in vivo behavioral sensitization","journal":"Molecular psychiatry","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (co-IP, peptide disruption, Ca2+ imaging, ERK signaling, electrophysiology, behavior); all converge on same conclusion; single lab but comprehensive","pmids":["25070539"],"is_preprint":false},{"year":2018,"finding":"Neurofilament light (NFL) protein interacts with GluN1 (NMDAR1) at synapses. NFL knockout reduces dendritic spines and GluN1 protein levels, elevates ubiquitin-dependent turnover of GluN1, increases hippocampal glutamate (by MRS), and depresses LTP. NFL+/- mice (at levels matching schizophrenia) show milder but similar NMDAR-related synaptic and behavioral deficits, indicating NFL stabilizes GluN1 at synapses.","method":"Co-immunoprecipitation of NFL and GluN1; NFL knockout and heterozygous mouse models; immunofluorescence; MRS; electrophysiology (LTP); behavioral tests","journal":"Translational psychiatry","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal co-IP plus loss-of-function mouse genetics with multiple orthogonal functional readouts (protein levels, ubiquitination, MRS, LTP, behavior)","pmids":["30143609"],"is_preprint":false},{"year":2014,"finding":"Triheteromeric GluN1/GluN2A/GluN2B NMDA receptors have glutamate deactivation kinetics and pharmacological sensitivity to subunit-selective antagonists (ifenprodil, CP-101,606, TCN-201) and Zn2+ that are distinct from diheteromeric GluN1/GluN2A and GluN1/GluN2B receptors. The ifenprodil binding site geometry differs in triheteromers compared to GluN1/GluN2B diheteromers.","method":"Selective cell-surface expression of recombinant triheteromeric receptors using a dominant-negative subunit strategy; whole-cell voltage-clamp electrophysiology; pharmacological characterization","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 1 / Strong — novel expression strategy to isolate triheteromers, combined with comprehensive electrophysiology and pharmacology; rigorous controls; important mechanistic paper","pmids":["24607230"],"is_preprint":false},{"year":2019,"finding":"GluN1/GluN3A receptors are functionally expressed in adult mouse medial habenula neurons and are activated by glycine alone (not glutamate). Glial cells tune neuronal activity via GluN1/GluN3A receptors; reducing GluN1/GluN3A levels in the MHb prevented place-aversion conditioning, demonstrating a role for these glycine-gated NMDAR subtype in control of aversive behavior.","method":"Electrophysiology in adult mouse brain slices with CGP-78608 to unmask GluN1/GluN3A currents; viral knockdown in medial habenula; conditioned place aversion behavioral test","journal":"Science","confidence":"High","confidence_rationale":"Tier 2 / Strong — electrophysiology in native adult tissue combined with in vivo loss-of-function and behavioral readout; landmark finding of native GluN1/GluN3A function","pmids":["31601771"],"is_preprint":false},{"year":2018,"finding":"GluN1/GluN3A receptors can be unmasked by CGP-78608 (which blocks GluN1 glycine site to prevent desensitization) and modulated by an endogenous GluN3A disulfide bond that controls redox sensitivity, agonist sensitivity, and gating kinetics. Under reducing conditions, ambient glycine is sufficient to tonically activate GluN1/GluN3A receptors in hippocampal neurons.","method":"Whole-cell voltage-clamp electrophysiology in HEK cells and hippocampal slices; redox manipulation; pharmacology with CGP-78608","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — reconstituted recombinant receptors plus native tissue electrophysiology; pharmacological and redox mechanistic dissection; multiple orthogonal approaches","pmids":["30425244"],"is_preprint":false},{"year":2019,"finding":"GluN1 alternative splicing controls nonionotropic (metabotropic) signaling by NMDARs. Glycine priming (binding to GluN1 glycine site without channel opening) induces receptor internalization only in GluN1 isoforms lacking the N1 cassette (exon 5); N1-containing isoforms block this nonionotropic signaling. C-terminal cassettes (C1, C2, C2') each permit glycine signaling. This was confirmed in CA1 pyramidal neurons (glycine priming present) vs. interneurons (glycine priming absent due to N1 expression).","method":"Recombinant receptor electrophysiology; engineered mouse knockin lines (GluN1 obligatorily containing or lacking N1 cassette); NMDAR internalization assays; electrophysiology in hippocampal CA1 pyramidal neurons and interneurons","journal":"Proceedings of the National Academy of Sciences","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — recombinant + in vivo knockin models + native neuron electrophysiology; multiple orthogonal approaches; single lab but comprehensive","pmids":["34187890"],"is_preprint":false},{"year":2019,"finding":"GluN1 exon 5 (N1 cassette) inclusion/exclusion controls LTP magnitude and spatial memory performance. Mice lacking the N1 cassette (GluN1a) show significantly enhanced hippocampal LTP and faster learning with better spatial memory compared to mice obligatorily expressing exon 5 (GluN1b), despite no differences in basal synaptic transmission.","method":"Generation of GluN1a (exon 5 knockout) and GluN1b (obligatory exon 5 expression) knockin mice; hippocampal slice LTP recordings; Morris water maze; novel object recognition behavioral tests","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vivo genetic knockin models combined with electrophysiology and multiple behavioral paradigms; rigorous controls and comparison between two engineered lines","pmids":["31875540"],"is_preprint":false},{"year":2021,"finding":"Cryo-EM structures of human GluN1-GluN2A NMDA receptor at ~4 Å reveal: competitive antagonists bound at GluN1 and GluN2A LBDs; a positive allosteric modulator shortens the distance between LBDs and TMD, stretching the gate open; the 'foot-in-the-door' blocker 9-aminoacridine binds within the LBD-TMD linker region (not the conventional TMD vestibule), providing molecular insights into crosstalk between LBDs and TMD during activation, inhibition, and allosteric transitions.","method":"Cryo-electron microscopy of full-length human GluN1-GluN2A NMDA receptor in complex with distinct ligands/modulators","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 1 / Moderate — high-resolution cryo-EM structures in multiple ligand states; single lab but structural evidence directly reveals mechanism; landmark structural paper","pmids":["34186027"],"is_preprint":false},{"year":2022,"finding":"Cryo-EM structures of human GluN1-GluN2C and GluN1-GluN2D NMDARs reveal unique inter-subunit and domain arrangements of GluN2C NMDARs, distinct from GluN2D. The GluN2C PAM (PYD-106) binding pocket is defined by these unique arrangements. Triheteromeric GluN1-2A-2C structure is also resolved.","method":"Single-particle cryo-electron microscopy of agonist-bound human GluN1-GluN2C, GluN1-GluN2A-GluN2C (triheteromeric), and GluN1-GluN2D receptors","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 1 / Moderate — multiple cryo-EM structures of distinct GluN2 subtypes; direct structural determination of allosteric modulator binding pocket; single lab but rigorous structural study","pmids":["36309015"],"is_preprint":false},{"year":2024,"finding":"Cryo-EM structures of GluN1/GluN3A NMDA receptors bound to antagonist (CNQX) and agonist (glycine) reveal a 1-3-1-3 heterotetrameric subunit arrangement. Glycine binding induces an unprecedented orientation shift in GluN3A subunits. Site-directed disruption of the unique glycine-bound subunit interface mitigates desensitization, establishing a structural basis for GluN3A-specific desensitization.","method":"Cryo-electron microscopy of GluN1/GluN3A NMDA receptors in agonist- and antagonist-bound states; site-directed mutagenesis of subunit interface with functional electrophysiology","journal":"Science advances","confidence":"High","confidence_rationale":"Tier 1 / Strong — cryo-EM structures in two functional states combined with mutagenesis validation; defines 1-3-1-3 arrangement and desensitization mechanism","pmids":["38598639"],"is_preprint":false},{"year":2013,"finding":"Specificity protein 4 (Sp4) functionally regulates transcription of GluN1, GluN2A, and GluN2B NMDA receptor subunit genes, operating complementarily and in parallel with NRF-1 and NRF-2. Sp1 and Sp3 do not regulate these subunits. Sp4 operates in a complementary and concurrent manner with NRF-1/NRF-2 to couple energy metabolism with neuronal activity at the transcriptional level.","method":"Promoter-reporter assays; ChIP; EMSA; siRNA knockdown; transfection in neurons and non-neuronal cells","journal":"Biochimica et biophysica acta","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple transcriptional methods (promoter-reporter, ChIP, EMSA, siRNA) in a single lab study","pmids":["23871830"],"is_preprint":false},{"year":2014,"finding":"Sp4 transcription factor activates transcription of Nwk2 (Nervous Wreck 2/Fchsd1), which in turn mediates Sp4-dependent regulation of cell surface expression of GluN1 (NR1) and dendrite patterning. Acute Sp4 depletion reduces surface but not total NR1; this is rescued by Nwk2 expression. Identifies a Sp4-Nwk2-NR1 pathway regulating NMDAR trafficking and neuronal morphogenesis.","method":"Promoter-luciferase reporter assays; siRNA knockdown of Sp4 and Nwk2 in cerebellar granule neurons; rescue experiments; surface vs. total NR1 quantification by immunostaining; dendrite morphology analysis","journal":"Developmental neurobiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reporter assays, knockdown with defined phenotypic readouts (surface NR1, dendrite number), rescue experiment; single lab","pmids":["25045015"],"is_preprint":false},{"year":2023,"finding":"KCTD13 (a substrate adaptor for Cullin3-E3 ubiquitin ligase) facilitates lysine-48-linked polyubiquitination of GluN1 at lysine 860, targeting it for degradation via the ubiquitin-proteasome pathway. KCTD13 knockdown in hippocampus reduces surface glutamate receptor expression, impairs glutamate synaptic transmission, and enhances seizure susceptibility; overexpression has the opposite effect.","method":"Co-immunoprecipitation to identify GluN1 as KCTD13 substrate; ubiquitination assay specifying K48-linkage; site-directed mutagenesis to identify K860 ubiquitination site; hippocampal knockdown/overexpression by viral vectors; electrophysiology; seizure susceptibility assays in TLE mouse model","journal":"Cell death and differentiation","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — identifies writer (KCTD13/Cullin3), modification (K48 ubiquitination), site (K860), and functional consequence (proteasomal degradation, altered surface expression, seizure threshold); multiple orthogonal methods","pmids":["37142655"],"is_preprint":false},{"year":2016,"finding":"De novo GRIN1 mutations clustering in transmembrane segments cause loss of NMDA receptor channel function with a dominant-negative effect (heterozygous mutations in transmembrane domains). Homozygous GRIN1 mutations (missense and truncation) also cause severe neurodevelopmental phenotypes. Functional characterization in Xenopus oocytes confirmed loss of channel function of varying severity.","method":"Two-electrode voltage-clamp in Xenopus oocytes expressing mutant GluN1 subunits; structural mapping of mutations onto 3D models; clinical genetics","journal":"Neurology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional electrophysiology in Xenopus oocytes for multiple variants; single expression system; mechanistic classification as dominant-negative loss-of-function","pmids":["27164704"],"is_preprint":false},{"year":2017,"finding":"The de novo GluN1-G620R mutation causes ~2-fold decrease in glutamate and glycine potency, strong decrease in Mg2+ block sensitivity, and significant reduction of current responses; GluN1-G620R/GluN2B complexes show significantly reduced delivery to the cell surface. This combination of trafficking defect and functional loss-of-function underlies the patient's neurodevelopmental phenotype.","method":"Electrophysiology (whole-cell patch-clamp) of GluN1-G620R/GluN2A and GluN1-G620R/GluN2B in HEK cells; surface trafficking assay (cell-surface biotinylation/immunofluorescence)","journal":"Journal of human genetics","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — electrophysiology combined with trafficking assay; two subunit combinations tested; clear mechanistic dissection of a pathogenic variant","pmids":["28228639"],"is_preprint":false},{"year":2021,"finding":"The recurrent de novo GluN1-M641I variant causes enhanced agonist potency and reduced Mg2+ block of NMDARs. These gain-of-function properties confer increased sensitivity to NMDAR channel blockers memantine, ketamine, and dextromethorphan compared to wild-type. Addition of memantine to the patient's treatment significantly reduced seizure burden.","method":"Two-electrode voltage-clamp in Xenopus oocytes and whole-cell recording in HEK cells; beta-lactamase reporter assay for surface expression; FDA-approved drug screening","journal":"Annals of clinical and translational neurology","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — electrophysiology in two expression systems plus drug screening with patient-level clinical validation; gain-of-function mechanism established","pmids":["34227748"],"is_preprint":false},{"year":2018,"finding":"GRIN1 mutations associated with polymicrogyria (clustering in the S2 ligand-binding domain region and adjacent M3 helix) significantly alter receptor activity in vitro. Three mutations increased agonist potency while one reduced proton inhibition—a gain-of-function profile distinct from loss-of-function seen in previous GRIN1 mutations.","method":"Two-electrode voltage-clamp and whole-cell voltage-clamp electrophysiology of mutant GluN1-containing receptors in Xenopus oocytes and transfected cells; whole-exome sequencing","journal":"Brain","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — electrophysiology in two expression systems characterizing multiple variants; mechanistic gain-of-function classification with agonist potency and proton inhibition assays","pmids":["29365063"],"is_preprint":false},{"year":2020,"finding":"Protocadherin 7 (PCDH7) interacts with the N-terminal domain of GluN1 (identified by unbiased screen of ~1,500 transmembrane proteins using purified GluN1-NTD bait). PCDH7 overexpression reduces synaptic NMDAR currents and induces dendritic structural changes; PCDH7 knockdown has opposing effects on dendritic morphology.","method":"Protein interaction screen using purified GluN1-NTD as bait against ~1,500 transmembrane proteins; primary neuron overexpression and knockdown; whole-cell electrophysiology; dendritic morphology analysis","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — unbiased interaction screen + functional validation in neurons with electrophysiology and morphology readouts; single lab; interaction binding confirmed but mechanism of NMDAR modulation not fully resolved","pmids":["32616769"],"is_preprint":false},{"year":2019,"finding":"Structural features of the glycine-binding site in GluN1 (and GluN3A) correlate with forward trafficking of NMDARs to the cell surface. Mutations in the GluN1 glycine-binding site alter surface delivery in both cell lines and primary hippocampal neurons, establishing that the glycine-binding site structure regulates receptor trafficking beyond just ligand binding.","method":"Site-directed mutagenesis of glycine-binding site residues; immunofluorescence and flow cytometry-based surface expression assays in HEK cells and primary rat hippocampal neurons","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — mutagenesis combined with surface expression quantification in two cell systems; single lab; clear mechanistic link between binding site structure and trafficking","pmids":["31444392"],"is_preprint":false},{"year":2022,"finding":"The pathogenic GluN1-N650K variant increases surface expression of GluN1/GluN2A and GluN1/GluN2B receptors (but not GluN1/GluN3A), enhances agonist potency, decreases conductance and open probability, and alters sensitivity to channel blockers memantine and ketamine. The K650 residue is located in the pore region; GluN1-N650K/GluN2B does not form functional receptors.","method":"Microscopy-based surface expression assays in HEK cells and hippocampal neurons; whole-cell patch-clamp electrophysiology; pharmacological profiling; excitotoxicity assays","journal":"Neuropharmacology","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — electrophysiology combined with trafficking assays and pharmacology in two cell systems; comprehensive mechanistic characterization of a single pathogenic variant","pmids":["36341805"],"is_preprint":false},{"year":2014,"finding":"In mice with selective Grin1 deletion in CRF neurons (especially in the CeA), fear memory acquisition and retention are enhanced without affecting fear extinction, exploration, or pain sensitivity. Amygdala Gria1 and Creb1 were elevated after fear conditioning in mutants, linking NMDAR function in CRF-CeA neurons to fear memory circuitry via AMPAR and CREB pathways.","method":"CRF-Cre × floxed Grin1 mice; CeA-targeted lentiviral Cre delivery; fear conditioning; RT-PCR for Gria1 and Creb1","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — cell-type-specific genetic knockout with behavioral readouts and molecular correlates; single lab; pathway placement via epistasis","pmids":["25340785"],"is_preprint":false},{"year":2022,"finding":"Platelet lineage-specific knockout of Grin1 (Pf4-Grin1-/- mice) causes defects in megakaryopoiesis, thrombopoiesis, and platelet function: reduced platelet counts, impaired platelet activation and spreading, reduced Ca2+ responses, and prolonged bleeding time. GluN1 deletion impairs F-actin and α-tubulin reorganization in megakaryocytes and reduces proplatelet formation, indicating NMDAR regulates PPF through MK-ECM interaction and cytoskeletal reorganization.","method":"Cre-loxP platelet lineage-specific Grin1 knockout; platelet function assays; calcium imaging; actin/tubulin immunofluorescence; colony and proplatelet formation assays; tail bleeding time; immune thrombocytopenia model","journal":"Blood","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vivo genetic model with comprehensive functional readouts (platelet counts, Ca2+ signaling, cytoskeletal analysis, bleeding time, colony formation); multiple orthogonal methods","pmids":["35245376"],"is_preprint":false},{"year":2017,"finding":"Anti-GluN1-S2 antibody (targeting the glycine-binding region of GluN1) inhibits human platelet activation, aggregation, and thrombus formation. The antibody epitope maps to α-helix H within the GluN1 glycine-binding clamshell; computational modeling predicts antibody binding impairs channel opening. This establishes GluN1 glycine-binding site function in platelet NMDARs that regulate thrombus formation.","method":"Platelet aggregation assays; thrombus formation under flow; epitope mapping by mutagenesis; crystal structure-based computational modeling; rat vaccination model","journal":"Platelets","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional antibody inhibition assays with epitope mapping and structural modeling; single lab; mechanism inferred from antibody binding site","pmids":["28277064"],"is_preprint":false},{"year":2024,"finding":"Transcription factor TFAP2A positively regulates Grin1 gene expression, as confirmed by dual-luciferase reporter assay. In satellite glial cells of the DRG, Tfap2a knockdown reduces Grin1 expression; Grin1 knockdown in DRG alleviates neuropathic pain. Tfap2a siRNA also reduces NMDA-induced proinflammatory cytokine upregulation in primary SGCs.","method":"Dual-luciferase reporter assay for TFAP2A regulation of Grin1 promoter; siRNA knockdown in vivo (intrathecal) and in primary SGCs; RT-PCR and immunostaining; pain behavioral tests","journal":"Biochemical pharmacology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reporter assay establishes transcriptional regulation; in vivo knockdown with behavioral readout; in vitro cellular confirmation; single lab","pmids":["39009095"],"is_preprint":false},{"year":2018,"finding":"Properties of triheteromeric GluN1/GluN1-1a/GluN1-1b/GluN2A and GluN1-1a/GluN1-1b/GluN2B receptors are intermediate between diheteromeric GluN1-1a/GluN1-1a/GluN2 and GluN1-1b/GluN1-1b/GluN2 receptors. A single copy of GluN3 pore residues strongly attenuates Mg2+ block and Ca2+ permeability; GluN1 and GluN2 pore residues contribute asymmetrically to Mg2+ block.","method":"FRET and FLIM to confirm triheteromeric assembly; selective surface expression strategy; whole-cell electrophysiology; pharmacological characterization; site-directed mutagenesis of pore residues","journal":"Molecular pharmacology","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — FRET/FLIM for assembly confirmation + electrophysiology + mutagenesis; rigorous demonstration of triheteromeric assembly and functional characterization","pmids":["29483146"],"is_preprint":false},{"year":2014,"finding":"GluN2 subunit is most likely directly responsible for the NMDA channel activation gate, while GluN1 assumes a role of more global control over gating conformational changes in GluN2. Specific mutations in the A7 residue of the SYTANLAAF motif in GluN1 (but not GluN2) result in channels with markedly enhanced affinity for both glycine and NMDA and can be activated by NMDA alone, suggesting GluN1 globally regulates GluN2 gating via this intersubunit interaction.","method":"Whole-cell patch-clamp electrophysiology; site-directed mutagenesis of SYTANLAAF motif A7 residue in GluN1 and GluN2; kinetic analysis of binding and unbinding rates","journal":"Pflugers Archiv","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — mutagenesis combined with detailed kinetic electrophysiology; single lab; mechanistic dissection of GluN1 vs GluN2 contributions to gating","pmids":["25339225"],"is_preprint":false},{"year":1995,"finding":"The human GRIN1 gene is composed of 21 exons distributed over ~31 kb on chromosome 9q34.3-qter. Exons 4, 20, and 21 are subject to alternative splicing (identical in sequence to rat alternatively spliced exons), indicating all eight NMDAR1 isoforms found in rat are also expressed in human brain. The promoter contains two copies of the even-skipped homeodomain recognition sequence, implicating homeobox protein control of developmental expression.","method":"Cosmid cloning and sequencing of human GRIN1 gene; FISH mapping to chromosome 9q34.3-qter; computer analysis of pre-mRNA secondary structure and promoter elements","journal":"Gene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct gene structure determination by sequencing and FISH; promoter element identification by sequence analysis; single lab; structural genomics establishes basis for splice isoform diversity","pmids":["7622053"],"is_preprint":false},{"year":2016,"finding":"Protons (extracellular acidification) potentiate GluN1/GluN3A receptor currents with half-maximal effect in the physiological pH range by slowing desensitization and accelerating recovery from desensitization. This modulation is mediated by residues at the heterodimer interface of the ligand-binding domain (GluN1 LBD interface with GluN3A).","method":"Whole-cell voltage-clamp of recombinant GluN1/GluN3A in HEK cells; site-directed mutagenesis of LBD interface residues; rapid solution exchange","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — mutagenesis identifies critical residues + electrophysiology characterizes mechanism; single lab; specific mechanistic assignment to LBD heterodimer interface","pmids":["27000430"],"is_preprint":false},{"year":2017,"finding":"GluN1 C-terminal alternatively spliced cassettes control steady-state activity level and pharmacological sensitivity (to zinc and protons) of GluN1/GluN3A receptors. Phosphorylation status of sites specific to certain GluN1 variants also modulates GluN1/GluN3A channel activity, indicating C-terminal domain splicing confers cell-specific and activity-dependent regulation.","method":"Whole-cell electrophysiology of recombinant GluN1 splice variants assembled with GluN3A in HEK293 cells; pharmacological characterization; phosphorylation state manipulation","journal":"Neuropharmacology","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — electrophysiology with defined splice variants and pharmacological tools; single lab; establishes role of C-terminal domain in receptor regulation","pmids":["28365212"],"is_preprint":false},{"year":2023,"finding":"The GluN1(Y668H) variant (associated with neurodevelopmental disorder) severely impairs surface expression of GluN1/GluN2A receptors, enhances sensitivity to glycine and glutamate by an order of magnitude, impairs Mg2+ block, reduces blocker (memantine/ketamine/MK-801) potency, and allows activation by either agonist alone. Single-channel recordings show this variant opens to multiple conductance levels more frequently than wild-type, revealing Y668 as a critical locus coupling receptor gating to ion channel conductance.","method":"Whole-cell and single-channel patch-clamp electrophysiology in HEK293 cells; surface expression assay; pharmacological profiling; primary hippocampal neuron recordings","journal":"Epilepsia","confidence":"High","confidence_rationale":"Tier 1 / Moderate — single-channel + whole-cell electrophysiology + surface expression assays; identifies specific structural locus (Y668) coupling gating to conductance; multiple readouts in single study","pmids":["37734923"],"is_preprint":false},{"year":2020,"finding":"EU1180-438, a negative allosteric modulator selective for GluN1/GluN3 receptors over GluN1/GluN2 NMDARs, inhibits GluN1/GluN3A currents in a voltage-independent, glycine concentration-independent manner. Site-directed mutagenesis identifies structural determinants of EU1180-438 activity near a short pre-M1 helix of GluN3 subunits. Non-stationary fluctuation analysis estimates native GluN1/GluN3A channel conductance at ~6.1 pS.","method":"Whole-cell electrophysiology of recombinant GluN1/GluN3 and GluN1/GluN2 receptors in HEK cells; native hippocampal CA1 neuron recordings; site-directed mutagenesis; non-stationary fluctuation analysis","journal":"Neuropharmacology","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — mutagenesis identifies binding site + functional characterization in recombinant and native systems + biophysical single-channel analysis; multiple orthogonal approaches","pmids":["32389749"],"is_preprint":false},{"year":2024,"finding":"α2δ-1 (a voltage-gated calcium channel regulatory subunit) interacts with NMDAR1 to form a complex that regulates NMDAR expression in the hypothalamus. Co-immunoprecipitation confirmed α2δ-1/NMDAR1 interaction. In α2δ-1 gene-knockout PC12 cells, quercetin had no effect on NMDAR1 expression, demonstrating the functional dependence of NMDAR1 regulation on α2δ-1.","method":"Co-immunoprecipitation; Western blot; immunofluorescence; α2δ-1 gene knockout in PC12 cells with NMDAR1 expression measurement; CUMS rat model","journal":"CNS neuroscience & therapeutics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP of interaction combined with functional gene-knockout validation; single lab; shows α2δ-1 dependence of NMDAR1 regulation","pmids":["38615365"],"is_preprint":false}],"current_model":"GluN1 (GRIN1) is the obligatory glycine-binding subunit of all NMDA receptor complexes, assembling as two GluN1 subunits with two GluN2 (or GluN3) subunits in an alternating 1/2/1/2 tetrameric arrangement at postsynaptic densities; the GluN1 N-terminal domain undergoes dynamic conformational changes that allosterically regulate GluN2-dependent gating, its ligand-binding domain (LBD) uses a conformational selection mechanism for glycine and undergoes multiple equilibrium conformations even when occupied, and its exon-5-encoded N1 cassette and C-terminal splice cassettes tune channel kinetics, open probability, nonionotropic (glycine-only) signaling, and allosteric modulation; GluN1 expression is controlled post-transcriptionally by mechanisms including NFL-dependent stabilization against ubiquitin-proteasomal degradation (with KCTD13 as an E3 adaptor ubiquitinating K860), transcriptionally by Sp4 (via Nwk2) and TFAP2A, and the receptor complex is directly bound by σ-1 receptor (at GluN1) and forms functional complexes with D1 dopamine receptors and α2δ-1 that regulate calcium influx, ERK signaling, and plasticity; beyond canonical glutamatergic synapses, GluN1/GluN3A receptors activated by glycine alone operate in adult brain regions (medial habenula, hippocampal CA1 neurons) to control aversive behavior and excitability, and NMDA receptors containing GluN1 are also functional in megakaryocytes where they regulate proplatelet formation through Ca2+ signaling and cytoskeletal reorganization."},"narrative":{"mechanistic_narrative":"GRIN1 encodes GluN1, the obligatory subunit of NMDA receptor complexes localized to postsynaptic densities of neurons throughout the hippocampus, cortex, and cerebellum [PMID:8301357]. Functional receptors assemble as alternating 1/2/1/2 tetramers in which GluN1 occupies the pore-proximal position relative to GluN2 [PMID:22493736], and GluN1 also forms 1-3-1-3 arrangements with GluN3A [PMID:38598639]. Within the complex GluN1 supplies the glycine-binding ligand-binding domain (LBD), whose apo state samples closed-cleft conformations by conformational selection and continues to transition among multiple cleft widths even when glycine is bound [PMID:23972471, PMID:26153703]; its N-terminal domain is conformationally dynamic and acts allosterically in trans to influence GluN2-dependent glutamate binding and gating [PMID:23454977]. GluN1 exerts global control over channel gating—mutations in its SYTANLAAF gating motif permit activation by NMDA alone [PMID:25339225]—and conformational freedom of its LBD-TMD linkers is required for pore opening, as revealed by cryo-EM structures defining how LBD-TMD crosstalk drives activation, allosteric potentiation, and channel block [PMID:21746848, PMID:34186027]. GluN1 alternative splicing tunes receptor behavior: the exon-5 N1 cassette accelerates deactivation, raises open probability, gates nonionotropic glycine-primed internalization, and sets the magnitude of hippocampal LTP and spatial learning [PMID:22641781, PMID:34187890, PMID:31875540], while C-terminal cassettes regulate GluN1/GluN3A activity and pharmacology [PMID:28365212]. GluN1/GluN3A receptors gated by glycine alone operate in adult medial habenula and CA1 neurons to control aversive behavior and excitability [PMID:31601771, PMID:30425244]. GluN1 abundance and surface delivery are controlled post-transcriptionally—neurofilament light stabilizes GluN1 against ubiquitin-proteasomal turnover [PMID:30143609], the Cullin3 adaptor KCTD13 drives K48-linked polyubiquitination at K860 to set surface receptor levels and seizure threshold [PMID:37142655]—and transcriptionally by Sp4 (via Nwk2) and TFAP2A [PMID:23871830, PMID:25045015, PMID:39009095]. GluN1 is directly bound by the σ-1 receptor, partners with D1 dopamine receptors to couple to ERK signaling and plasticity, and associates with α2δ-1, PCDH7, and protons that modulate gating and trafficking [PMID:24227730, PMID:25070539, PMID:38615365, PMID:32616769, PMID:27000430]. De novo GRIN1 mutations cause severe neurodevelopmental disorders through either dominant-negative loss of channel function or gain-of-function alterations in agonist potency, Mg2+ block, and trafficking [PMID:27164704, PMID:34227748, PMID:29365063, PMID:37734923]. Beyond the nervous system, GluN1-containing NMDA receptors in megakaryocytes regulate proplatelet formation through Ca2+ signaling and cytoskeletal reorganization [PMID:35245376, PMID:28277064].","teleology":[{"year":1994,"claim":"Establishing where GluN1 acts answered whether it is a synaptic receptor component, placing it at the postsynaptic membrane of central neurons.","evidence":"Ultrastructural immunocytochemistry on rat nervous system sections","pmids":["8301357"],"confidence":"High","gaps":["Did not resolve subunit stoichiometry or partner subunits","No functional measurement at characterized synapses"]},{"year":1995,"claim":"Defining the human GRIN1 gene structure established the genomic basis for the eight splice isoforms and implicated developmental promoter control.","evidence":"Cosmid cloning, sequencing, and FISH mapping of human GRIN1","pmids":["7622053"],"confidence":"Medium","gaps":["Functional consequences of individual isoforms not tested","Homeodomain promoter control inferred from sequence, not assayed"]},{"year":1998,"claim":"Identifying NRSE/NRSF, single-stranded DNA-binding proteins, and later Sp4/Nwk2 and TFAP2A answered how GluN1 transcription is restricted to neurons and coupled to activity and signaling.","evidence":"Promoter deletion, EMSA, ChIP, reporter assays, and siRNA across cell systems and DRG/SGCs","pmids":["9422773","23871830","25045015","39009095"],"confidence":"Medium","gaps":["Relative contribution of each factor in vivo unresolved","Sp4-Nwk2 surface-trafficking link characterized only in cerebellar granule neurons"]},{"year":1997,"claim":"Dissociating mRNA from protein regulation showed GluN1 expression is dominated by post-transcriptional and local-synthesis control rather than transcript abundance.","evidence":"Parallel immunofluorescence and in situ hybridization in PC12 cells, estradiol-treated rats, and lesioned hippocampus","pmids":["8226739","8824322","9045729"],"confidence":"High","gaps":["Molecular machinery of local translation not identified","Did not pinpoint the post-transcriptional checkpoint"]},{"year":2013,"claim":"Defining GluN1 LBD and NTD dynamics answered how the glycine site engages ligand and how the N-terminal domain allosterically tunes gating.","evidence":"X-ray crystallography, smFRET, computational free-energy landscapes, mutagenesis, and electrophysiology of recombinant receptors","pmids":["23972471","23454977","26153703","24072709"],"confidence":"High","gaps":["Link between isolated-domain dynamics and full-length channel gating inferred","Functional role of long-lived intermediate cleft states unresolved"]},{"year":2012,"claim":"Establishing the 1/2/1/2 arrangement and the requirement for LBD-TMD linker freedom answered how GluN1 is positioned in the tetramer and how it transmits force to the pore.","evidence":"Disulfide cross-linking with functional recording and structural homology modeling","pmids":["22493736","21746848"],"confidence":"High","gaps":["Mature vs immature arrangement differences not structurally resolved at the time","Inter-subunit gating coupling detail limited to engineered constraints"]},{"year":2014,"claim":"Showing GluN1 globally controls GluN2 gating and characterizing triheteromers clarified the division of labor among subunits in activation and pharmacology.","evidence":"SYTANLAAF mutagenesis with kinetic analysis; dominant-negative and FRET/FLIM triheteromer expression strategies with pharmacology","pmids":["25339225","24607230","29483146"],"confidence":"High","gaps":["Native abundance of specific triheteromers in vivo not quantified","Structural basis of asymmetric pore contributions resolved later"]},{"year":2013,"claim":"Identifying direct binding of σ-1 receptor and D1 dopamine receptors to GluN1 answered how the receptor is allosterically and signal-transductively coupled to other receptor systems.","evidence":"AFM imaging, co-IP, proximity ligation, blocking peptide, Ca2+/ERK assays, slice electrophysiology, and behavior","pmids":["24227730","25070539"],"confidence":"High","gaps":["Stoichiometry and structural interface of these complexes unresolved","Whether σ-1 and D1R compete or co-occupy GluN1 not addressed"]},{"year":2016,"claim":"Functional characterization of de novo GRIN1 variants answered how mutations cause disease, distinguishing dominant-negative loss-of-function from gain-of-function mechanisms.","evidence":"Two-electrode and whole-cell voltage-clamp of variants in oocytes/HEK cells with trafficking and pharmacological profiling, plus clinical genetics","pmids":["27164704","28228639","29365063","34227748","37734923","36341805"],"confidence":"High","gaps":["Genotype-to-phenotype prediction across the variant spectrum incomplete","In vivo neuronal consequences of each variant not modeled"]},{"year":2018,"claim":"Discovering native glycine-gated GluN1/GluN3A receptors and their structural basis answered whether GluN1 supports non-canonical signaling in adult brain.","evidence":"Native and recombinant electrophysiology with CGP-78608, redox manipulation, proton modulation, selective NAMs, viral knockdown, behavior, and cryo-EM","pmids":["30425244","31601771","27000430","32389749","28365212","38598639"],"confidence":"High","gaps":["Endogenous ligands and physiological triggers in vivo only partly defined","Cell-type distribution of GluN3A-containing receptors incompletely mapped"]},{"year":2018,"claim":"Identifying NFL, KCTD13, PCDH7, α2δ-1, and glycine-site structure as regulators answered how GluN1 protein stability and surface delivery are controlled.","evidence":"Co-IP, ubiquitination assays with site mapping, interaction screen, knockout/knockdown mouse and cell models with electrophysiology and trafficking readouts","pmids":["30143609","37142655","32616769","38615365","31444392"],"confidence":"High","gaps":["Integration of these regulators into a single trafficking pathway unresolved","PCDH7 and α2δ-1 mechanisms of NMDAR modulation not fully resolved"]},{"year":2021,"claim":"Cryo-EM of full-length human GluN1-GluN2A/C/D and GluN1/GluN3A receptors answered how ligands, allosteric modulators, and blockers act on the assembled receptor.","evidence":"Single-particle cryo-EM in multiple ligand and subunit states with mutagenesis validation","pmids":["34186027","36309015","38598639"],"confidence":"High","gaps":["Dynamic gating transitions inferred from static states","Triheteromeric receptor structures resolved for limited subunit combinations"]},{"year":2022,"claim":"Platelet-lineage Grin1 deletion answered whether GluN1 has a non-neuronal function, revealing a role in megakaryopoiesis and proplatelet formation.","evidence":"Cre-loxP lineage-specific knockout, platelet function and Ca2+ assays, cytoskeletal imaging, antibody inhibition, and bleeding-time measurement","pmids":["35245376","28277064"],"confidence":"High","gaps":["Subunit composition of megakaryocyte NMDARs not defined","Upstream activating ligand in platelet lineage unclear"]},{"year":null,"claim":"How the many regulators of GluN1 abundance, splicing, and partner assembly are integrated to set receptor composition at specific synapses in vivo remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unified model linking transcriptional, post-transcriptional, and trafficking control","Spatiotemporal logic of isoform and GluN2/GluN3 partner selection unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[11,39,16,43]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[8,39]},{"term_id":"GO:0005215","term_label":"transporter activity","supporting_discovery_ids":[35,38]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,7,28,33]}],"pathway":[{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[0,17,20]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[14,6]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[27,29,30,43]},{"term_id":"R-HSA-109582","term_label":"Hemostasis","supporting_discovery_ids":[35,36]}],"complexes":["NMDA receptor (GluN1/GluN2)","GluN1/GluN3A receptor","postsynaptic density","D1R/GluN1 complex"],"partners":["GRIN2A","GRIN3A","SIGMAR1","DRD1","NEFL","KCTD13","PCDH7","CACNA2D1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q05586","full_name":"Glutamate receptor ionotropic, NMDA 1","aliases":["Glutamate [NMDA] receptor subunit zeta-1","N-methyl-D-aspartate receptor subunit NR1","NMD-R1","hNR1"],"length_aa":938,"mass_kda":105.4,"function":"Component of N-methyl-D-aspartate (NMDA) receptors (NMDARs) that function as heterotetrameric, ligand-gated cation channels with high calcium permeability and voltage-dependent block by Mg(2+) (PubMed:21376300, PubMed:26875626, PubMed:26919761, PubMed:28126851, PubMed:28228639, PubMed:36959261, PubMed:7679115, PubMed:7681588, PubMed:7685113). NMDARs participate in synaptic plasticity for learning and memory formation by contributing to the long-term potentiation (LTP) (PubMed:26875626). Channel activation requires binding of the neurotransmitter L-glutamate to the GluN2 subunit, glycine or D-serine binding to the GluN1 subunit, plus membrane depolarization to eliminate channel inhibition by Mg(2+) (PubMed:21376300, PubMed:26875626, PubMed:26919761, PubMed:27164704, PubMed:28095420, PubMed:28105280, PubMed:28126851, PubMed:28228639, PubMed:36959261, PubMed:38538865, PubMed:7679115, PubMed:7681588, PubMed:7685113). NMDARs mediate simultaneously the potassium efflux and the influx of calcium and sodium (By similarity). Each GluN2 or GluN3 subunit confers differential attributes to channel properties, including activation, deactivation and desensitization kinetics, pH sensitivity, Ca2(+) permeability, and binding to allosteric modulators (PubMed:26875626, PubMed:26919761, PubMed:36309015, PubMed:38598639)","subcellular_location":"Cell membrane; Postsynaptic cell membrane; Postsynaptic density membrane; Synaptic cell membrane","url":"https://www.uniprot.org/uniprotkb/Q05586/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/GRIN1","classification":"Not Classified","n_dependent_lines":1,"n_total_lines":1208,"dependency_fraction":0.0008278145695364238},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/GRIN1","total_profiled":1310},"omim":[{"mim_id":"619814","title":"DEVELOPMENTAL AND EPILEPTIC ENCEPHALOPATHY 101; DEE101","url":"https://www.omim.org/entry/619814"},{"mim_id":"618306","title":"PROLINE-RICH PROTEIN 7; PRR7","url":"https://www.omim.org/entry/618306"},{"mim_id":"617820","title":"NEURODEVELOPMENTAL DISORDER WITH OR WITHOUT HYPERKINETIC MOVEMENTS AND SEIZURES, AUTOSOMAL RECESSIVE; NDHMSR","url":"https://www.omim.org/entry/617820"},{"mim_id":"616690","title":"CENTROSOMAL PROTEIN, 104-KD; CEP104","url":"https://www.omim.org/entry/616690"},{"mim_id":"614795","title":"1-@ACYLGLYCEROL-3-PHOSPHATE O-ACYLTRANSFERASE 4; AGPAT4","url":"https://www.omim.org/entry/614795"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"brain","ntpm":215.2}],"url":"https://www.proteinatlas.org/search/GRIN1"},"hgnc":{"alias_symbol":["GluN1","NR1"],"prev_symbol":["NMDAR1"]},"alphafold":{"accession":"Q05586","domains":[{"cath_id":"3.40.50.2300","chopping":"21-114_277-334","consensus_level":"high","plddt":87.3249,"start":21,"end":334},{"cath_id":"3.40.50.2300","chopping":"143-273_349-373","consensus_level":"high","plddt":90.69,"start":143,"end":373},{"cath_id":"3.40.190.10","chopping":"398-532","consensus_level":"high","plddt":89.4225,"start":398,"end":532},{"cath_id":"3.40.190.10","chopping":"534-547_660-758","consensus_level":"medium","plddt":91.0427,"start":534,"end":758},{"cath_id":"1.10.287.70","chopping":"559-585_600-656","consensus_level":"high","plddt":86.7213,"start":559,"end":656}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q05586","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q05586-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q05586-F1-predicted_aligned_error_v6.png","plddt_mean":82.88},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=GRIN1","jax_strain_url":"https://www.jax.org/strain/search?query=GRIN1"},"sequence":{"accession":"Q05586","fasta_url":"https://rest.uniprot.org/uniprotkb/Q05586.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q05586/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q05586"}},"corpus_meta":[{"pmid":"8301357","id":"PMC_8301357","title":"Light and electron microscope distribution of the NMDA receptor subunit NMDAR1 in the rat nervous system using a selective anti-peptide antibody.","date":"1994","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/8301357","citation_count":802,"is_preprint":false},{"pmid":"8613793","id":"PMC_8613793","title":"Drugs of abuse and stress increase the expression of GluR1 and NMDAR1 glutamate receptor subunits in the rat ventral tegmental area: common adaptations among cross-sensitizing agents.","date":"1996","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/8613793","citation_count":372,"is_preprint":false},{"pmid":"8824322","id":"PMC_8824322","title":"Differential regulation of NMDAR1 mRNA and protein by estradiol in the rat hippocampus.","date":"1996","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/8824322","citation_count":317,"is_preprint":false},{"pmid":"24607230","id":"PMC_24607230","title":"Distinct functional and pharmacological properties of Triheteromeric GluN1/GluN2A/GluN2B NMDA receptors.","date":"2014","source":"Neuron","url":"https://pubmed.ncbi.nlm.nih.gov/24607230","citation_count":260,"is_preprint":false},{"pmid":"27164704","id":"PMC_27164704","title":"Delineating the GRIN1 phenotypic spectrum: A distinct genetic NMDA receptor encephalopathy.","date":"2016","source":"Neurology","url":"https://pubmed.ncbi.nlm.nih.gov/27164704","citation_count":147,"is_preprint":false},{"pmid":"8226739","id":"PMC_8226739","title":"Expression of endogenous NMDAR1 transcripts without receptor protein suggests post-transcriptional control in PC12 cells.","date":"1993","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/8226739","citation_count":145,"is_preprint":false},{"pmid":"9832144","id":"PMC_9832144","title":"Expression of NMDAR1, GluR1, GluR7, and KA1 glutamate receptor mRNAs is decreased in frontal cortex of \"neuroleptic-free\" schizophrenics: evidence on reversible up-regulation by typical neuroleptics.","date":"1998","source":"Journal of neurochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/9832144","citation_count":145,"is_preprint":false},{"pmid":"9045729","id":"PMC_9045729","title":"Differential subcellular regulation of NMDAR1 protein and mRNA in dendrites of dentate gyrus granule cells after perforant path transection.","date":"1997","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/9045729","citation_count":95,"is_preprint":false},{"pmid":"12610658","id":"PMC_12610658","title":"Evidence that the N-methyl-D-aspartate subunit 1 receptor gene (GRIN1) confers susceptibility to bipolar disorder.","date":"2003","source":"Molecular psychiatry","url":"https://pubmed.ncbi.nlm.nih.gov/12610658","citation_count":90,"is_preprint":false},{"pmid":"15841096","id":"PMC_15841096","title":"An association study of the N-methyl-D-aspartate receptor NR1 subunit gene (GRIN1) and NR2B subunit gene (GRIN2B) in schizophrenia with universal DNA microarray.","date":"2005","source":"European journal of human genetics : EJHG","url":"https://pubmed.ncbi.nlm.nih.gov/15841096","citation_count":86,"is_preprint":false},{"pmid":"24227730","id":"PMC_24227730","title":"The σ-1 receptor interacts directly with GluN1 but not GluN2A in the GluN1/GluN2A NMDA receptor.","date":"2013","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/24227730","citation_count":84,"is_preprint":false},{"pmid":"30425244","id":"PMC_30425244","title":"Unmasking GluN1/GluN3A excitatory glycine NMDA receptors.","date":"2018","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/30425244","citation_count":83,"is_preprint":false},{"pmid":"23972471","id":"PMC_23972471","title":"Conformational analysis of NMDA receptor GluN1, GluN2, and GluN3 ligand-binding domains reveals subtype-specific characteristics.","date":"2013","source":"Structure (London, England : 1993)","url":"https://pubmed.ncbi.nlm.nih.gov/23972471","citation_count":83,"is_preprint":false},{"pmid":"31601771","id":"PMC_31601771","title":"Control of aversion by glycine-gated GluN1/GluN3A NMDA receptors in the adult medial habenula.","date":"2019","source":"Science (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/31601771","citation_count":83,"is_preprint":false},{"pmid":"29365063","id":"PMC_29365063","title":"De novo mutations in GRIN1 cause extensive bilateral polymicrogyria.","date":"2018","source":"Brain : a journal of neurology","url":"https://pubmed.ncbi.nlm.nih.gov/29365063","citation_count":78,"is_preprint":false},{"pmid":"25864721","id":"PMC_25864721","title":"GRIN1 mutations cause encephalopathy with infantile-onset epilepsy, and hyperkinetic and stereotyped movement disorders.","date":"2015","source":"Epilepsia","url":"https://pubmed.ncbi.nlm.nih.gov/25864721","citation_count":74,"is_preprint":false},{"pmid":"28228639","id":"PMC_28228639","title":"GRIN1 mutation associated with intellectual disability alters NMDA receptor trafficking and function.","date":"2017","source":"Journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/28228639","citation_count":68,"is_preprint":false},{"pmid":"11844485","id":"PMC_11844485","title":"Age-related changes in GluR2 and NMDAR1 glutamate receptor subunit protein immunoreactivity in corticocortically projecting neurons in macaque and patas monkeys.","date":"2002","source":"Brain research","url":"https://pubmed.ncbi.nlm.nih.gov/11844485","citation_count":67,"is_preprint":false},{"pmid":"25070539","id":"PMC_25070539","title":"D1R/GluN1 complexes in the striatum integrate dopamine and glutamate signalling to control synaptic plasticity and cocaine-induced responses.","date":"2014","source":"Molecular psychiatry","url":"https://pubmed.ncbi.nlm.nih.gov/25070539","citation_count":65,"is_preprint":false},{"pmid":"9464997","id":"PMC_9464997","title":"NMDAR1 glutamate receptor subunit isoforms in neostriatal, neocortical, and hippocampal nitric oxide synthase neurons.","date":"1998","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/9464997","citation_count":62,"is_preprint":false},{"pmid":"23454977","id":"PMC_23454977","title":"Allosteric signaling and dynamics of the clamshell-like NMDA receptor GluN1 N-terminal domain.","date":"2013","source":"Nature structural & molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/23454977","citation_count":61,"is_preprint":false},{"pmid":"31541561","id":"PMC_31541561","title":"Functional and pharmacological properties of triheteromeric GluN1/2B/2D NMDA receptors.","date":"2019","source":"The Journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/31541561","citation_count":59,"is_preprint":false},{"pmid":"34186027","id":"PMC_34186027","title":"Gating mechanism and a modulatory niche of human GluN1-GluN2A NMDA receptors.","date":"2021","source":"Neuron","url":"https://pubmed.ncbi.nlm.nih.gov/34186027","citation_count":57,"is_preprint":false},{"pmid":"22641781","id":"PMC_22641781","title":"GluN1 splice variant control of GluN1/GluN2D NMDA receptors.","date":"2012","source":"The Journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/22641781","citation_count":56,"is_preprint":false},{"pmid":"29258835","id":"PMC_29258835","title":"The GluN1/GluN2B NMDA receptor and metabotropic glutamate receptor 1 negative allosteric modulator has enhanced neuroprotection in a rat subarachnoid hemorrhage model.","date":"2017","source":"Experimental neurology","url":"https://pubmed.ncbi.nlm.nih.gov/29258835","citation_count":52,"is_preprint":false},{"pmid":"9422773","id":"PMC_9422773","title":"Single-stranded DNA-binding proteins and neuron-restrictive silencer factor participate in cell-specific transcriptional control of the NMDAR1 gene.","date":"1998","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/9422773","citation_count":50,"is_preprint":false},{"pmid":"30143609","id":"PMC_30143609","title":"Neurofilament light interaction with GluN1 modulates neurotransmission and schizophrenia-associated behaviors.","date":"2018","source":"Translational psychiatry","url":"https://pubmed.ncbi.nlm.nih.gov/30143609","citation_count":47,"is_preprint":false},{"pmid":"33612107","id":"PMC_33612107","title":"Anti-NMDAR encephalitis induced in mice by active immunization with a peptide from the amino-terminal domain of the GluN1 subunit.","date":"2021","source":"Journal of neuroinflammation","url":"https://pubmed.ncbi.nlm.nih.gov/33612107","citation_count":45,"is_preprint":false},{"pmid":"28133447","id":"PMC_28133447","title":"GluN1 and GluN2A NMDA Receptor Subunits Increase in the Hippocampus during Memory Consolidation in the Rat.","date":"2017","source":"Frontiers in behavioral neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/28133447","citation_count":45,"is_preprint":false},{"pmid":"31875540","id":"PMC_31875540","title":"Control of Long-Term Synaptic Potentiation and Learning by Alternative Splicing of the NMDA Receptor Subunit GluN1.","date":"2019","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/31875540","citation_count":45,"is_preprint":false},{"pmid":"36309015","id":"PMC_36309015","title":"Structural insights into assembly and function of GluN1-2C, GluN1-2A-2C, and GluN1-2D NMDARs.","date":"2022","source":"Molecular cell","url":"https://pubmed.ncbi.nlm.nih.gov/36309015","citation_count":42,"is_preprint":false},{"pmid":"20204507","id":"PMC_20204507","title":"Expression of the hippocampal NMDA receptor GluN1 subunit and its splicing isoforms in schizophrenia: postmortem study.","date":"2010","source":"Neurochemical research","url":"https://pubmed.ncbi.nlm.nih.gov/20204507","citation_count":40,"is_preprint":false},{"pmid":"37248111","id":"PMC_37248111","title":"Excitatory GluN1/GluN3A glycine receptors (eGlyRs) in brain signaling.","date":"2023","source":"Trends in neurosciences","url":"https://pubmed.ncbi.nlm.nih.gov/37248111","citation_count":39,"is_preprint":false},{"pmid":"7689684","id":"PMC_7689684","title":"Quantitation of NMDA receptor (NMDAR1) mRNA levels in the adult and developing rat CNS.","date":"1993","source":"Brain research. Molecular brain research","url":"https://pubmed.ncbi.nlm.nih.gov/7689684","citation_count":39,"is_preprint":false},{"pmid":"21919190","id":"PMC_21919190","title":"Association of GRIN1 and GRIN2A-D with schizophrenia and genetic interaction with maternal herpes simplex virus-2 infection affecting disease risk.","date":"2011","source":"American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/21919190","citation_count":39,"is_preprint":false},{"pmid":"21746848","id":"PMC_21746848","title":"Local constraints in either the GluN1 or GluN2 subunit equally impair NMDA receptor pore opening.","date":"2011","source":"The Journal of general physiology","url":"https://pubmed.ncbi.nlm.nih.gov/21746848","citation_count":36,"is_preprint":false},{"pmid":"32389749","id":"PMC_32389749","title":"Negative allosteric modulation of GluN1/GluN3 NMDA receptors.","date":"2020","source":"Neuropharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/32389749","citation_count":34,"is_preprint":false},{"pmid":"31512412","id":"PMC_31512412","title":"Rett and Rett-like syndrome: Expanding the genetic spectrum to KIF1A and GRIN1 gene.","date":"2019","source":"Molecular genetics & genomic medicine","url":"https://pubmed.ncbi.nlm.nih.gov/31512412","citation_count":34,"is_preprint":false},{"pmid":"24172336","id":"PMC_24172336","title":"A combinatorial approach of Proteomics and Systems Biology in unravelling the mechanisms of acute kidney injury (AKI): involvement of NMDA receptor GRIN1 in murine AKI.","date":"2013","source":"BMC systems biology","url":"https://pubmed.ncbi.nlm.nih.gov/24172336","citation_count":32,"is_preprint":false},{"pmid":"17728671","id":"PMC_17728671","title":"Possible association between genetic variants at the GRIN1 gene and schizophrenia with lifetime history of depressive symptoms in a German sample.","date":"2007","source":"Psychiatric genetics","url":"https://pubmed.ncbi.nlm.nih.gov/17728671","citation_count":32,"is_preprint":false},{"pmid":"29483146","id":"PMC_29483146","title":"Properties of Triheteromeric N-Methyl-d-Aspartate Receptors Containing Two Distinct GluN1 Isoforms.","date":"2018","source":"Molecular pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/29483146","citation_count":31,"is_preprint":false},{"pmid":"7622053","id":"PMC_7622053","title":"Cloning and structure of the gene encoding the human N-methyl-D-aspartate receptor (NMDAR1).","date":"1995","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/7622053","citation_count":31,"is_preprint":false},{"pmid":"9138725","id":"PMC_9138725","title":"Quantitative localization of NMDAR1 receptor subunit immunoreactivity in inferotemporal and prefrontal association cortices of monkey and human.","date":"1997","source":"Brain research","url":"https://pubmed.ncbi.nlm.nih.gov/9138725","citation_count":31,"is_preprint":false},{"pmid":"7707878","id":"PMC_7707878","title":"Distribution of NMDAR1 receptor subunit mRNA and [125I]MK-801 binding in the hypothalamus of intact, castrate and castrate-DHTP treated male rats.","date":"1995","source":"Brain research. Molecular brain research","url":"https://pubmed.ncbi.nlm.nih.gov/7707878","citation_count":31,"is_preprint":false},{"pmid":"38615365","id":"PMC_38615365","title":"Quercetin alleviates chronic unpredictable mild stress-induced depression-like behavior by inhibiting NMDAR1 with α2δ-1 in rats.","date":"2024","source":"CNS neuroscience & therapeutics","url":"https://pubmed.ncbi.nlm.nih.gov/38615365","citation_count":30,"is_preprint":false},{"pmid":"34227748","id":"PMC_34227748","title":"Recurrent seizure-related GRIN1 variant: Molecular mechanism and targeted therapy.","date":"2021","source":"Annals of clinical and translational neurology","url":"https://pubmed.ncbi.nlm.nih.gov/34227748","citation_count":30,"is_preprint":false},{"pmid":"8041510","id":"PMC_8041510","title":"NMDA receptor (NMDAR1) expression in the rat hippocampus after forebrain ischemia.","date":"1994","source":"Neuroscience letters","url":"https://pubmed.ncbi.nlm.nih.gov/8041510","citation_count":30,"is_preprint":false},{"pmid":"22493736","id":"PMC_22493736","title":"An alternating GluN1-2-1-2 subunit arrangement in mature NMDA receptors.","date":"2012","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/22493736","citation_count":30,"is_preprint":false},{"pmid":"19861419","id":"PMC_19861419","title":"GRIN1 regulates micro-opioid receptor activities by tethering the receptor and G protein in the lipid raft.","date":"2009","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/19861419","citation_count":28,"is_preprint":false},{"pmid":"15383322","id":"PMC_15383322","title":"Role of the metabotropic P2Y(4) receptor during hypoglycemia: cross talk with the ionotropic NMDAR1 receptor.","date":"2004","source":"Experimental cell research","url":"https://pubmed.ncbi.nlm.nih.gov/15383322","citation_count":28,"is_preprint":false},{"pmid":"30099049","id":"PMC_30099049","title":"7-Methoxyderivative of tacrine is a 'foot-in-the-door' open-channel blocker of GluN1/GluN2 and GluN1/GluN3 NMDA receptors with neuroprotective activity in vivo.","date":"2018","source":"Neuropharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/30099049","citation_count":28,"is_preprint":false},{"pmid":"20438806","id":"PMC_20438806","title":"Association analysis of GRIN1 and GRIN2B polymorphisms and Parkinson's disease in a hospital-based case-control study.","date":"2010","source":"Neuroscience letters","url":"https://pubmed.ncbi.nlm.nih.gov/20438806","citation_count":27,"is_preprint":false},{"pmid":"27000430","id":"PMC_27000430","title":"Protons Potentiate GluN1/GluN3A Currents by Attenuating Their Desensitisation.","date":"2016","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/27000430","citation_count":27,"is_preprint":false},{"pmid":"38836461","id":"PMC_38836461","title":"Disease-Associated Variants in GRIN1, GRIN2A and GRIN2B genes: Insights into NMDA Receptor Structure, Function, and Pathophysiology.","date":"2024","source":"Physiological research","url":"https://pubmed.ncbi.nlm.nih.gov/38836461","citation_count":26,"is_preprint":false},{"pmid":"25340785","id":"PMC_25340785","title":"Grin1 receptor deletion within CRF neurons enhances fear memory.","date":"2014","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/25340785","citation_count":26,"is_preprint":false},{"pmid":"11109007","id":"PMC_11109007","title":"Mutation analysis of the N-methyl-D-aspartate receptor NR1 subunit gene (GRIN1) in schizophrenia.","date":"2000","source":"Neuroscience letters","url":"https://pubmed.ncbi.nlm.nih.gov/11109007","citation_count":26,"is_preprint":false},{"pmid":"28264232","id":"PMC_28264232","title":"Memantine Induces NMDAR1-Mediated Autophagic Cell Death in Malignant Glioma Cells.","date":"2017","source":"Journal of Korean Neurosurgical Society","url":"https://pubmed.ncbi.nlm.nih.gov/28264232","citation_count":26,"is_preprint":false},{"pmid":"9878792","id":"PMC_9878792","title":"Expression of glutamate receptor subunit/subtype messenger RNAS for NMDAR1, GLuR1, GLuR2 and mGLuR5 by accumbal projection neurons.","date":"1999","source":"Brain research. Molecular brain research","url":"https://pubmed.ncbi.nlm.nih.gov/9878792","citation_count":26,"is_preprint":false},{"pmid":"24072709","id":"PMC_24072709","title":"Crystal structure and pharmacological characterization of a novel N-methyl-D-aspartate (NMDA) receptor antagonist at the GluN1 glycine binding site.","date":"2013","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/24072709","citation_count":26,"is_preprint":false},{"pmid":"23688147","id":"PMC_23688147","title":"ENU-mutagenesis mice with a non-synonymous mutation in Grin1 exhibit abnormal anxiety-like behaviors, impaired fear memory, and decreased acoustic startle response.","date":"2013","source":"BMC research notes","url":"https://pubmed.ncbi.nlm.nih.gov/23688147","citation_count":26,"is_preprint":false},{"pmid":"23871830","id":"PMC_23871830","title":"Specificity protein 4 functionally regulates the transcription of NMDA receptor subunits GluN1, GluN2A, and GluN2B.","date":"2013","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/23871830","citation_count":26,"is_preprint":false},{"pmid":"31444392","id":"PMC_31444392","title":"Structural features in the glycine-binding sites of the GluN1 and GluN3A subunits regulate the surface delivery of NMDA receptors.","date":"2019","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/31444392","citation_count":26,"is_preprint":false},{"pmid":"38598639","id":"PMC_38598639","title":"Structure and function of GluN1-3A NMDA receptor excitatory glycine receptor channel.","date":"2024","source":"Science advances","url":"https://pubmed.ncbi.nlm.nih.gov/38598639","citation_count":25,"is_preprint":false},{"pmid":"32616769","id":"PMC_32616769","title":"PCDH7 interacts with GluN1 and regulates dendritic spine morphology and synaptic function.","date":"2020","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/32616769","citation_count":25,"is_preprint":false},{"pmid":"15488195","id":"PMC_15488195","title":"Identification and biochemical analysis of GRIN1 and GRIN2.","date":"2004","source":"Methods in enzymology","url":"https://pubmed.ncbi.nlm.nih.gov/15488195","citation_count":25,"is_preprint":false},{"pmid":"20345915","id":"PMC_20345915","title":"Phenotypic characterization of a new Grin1 mutant mouse generated by ENU mutagenesis.","date":"2010","source":"The European journal of neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/20345915","citation_count":25,"is_preprint":false},{"pmid":"31732832","id":"PMC_31732832","title":"Ligustrazine suppresses renal NMDAR1 and caspase-3 expressions in a mouse model of sepsis-associated acute kidney injury.","date":"2019","source":"Molecular and cellular biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/31732832","citation_count":25,"is_preprint":false},{"pmid":"18792810","id":"PMC_18792810","title":"Association between the G1001C polymorphism in the GRIN1 gene promoter and schizophrenia in the Iranian population.","date":"2008","source":"Journal of molecular neuroscience : MN","url":"https://pubmed.ncbi.nlm.nih.gov/18792810","citation_count":25,"is_preprint":false},{"pmid":"37142655","id":"PMC_37142655","title":"KCTD13-mediated ubiquitination and degradation of GluN1 regulates excitatory synaptic transmission and seizure susceptibility.","date":"2023","source":"Cell death and differentiation","url":"https://pubmed.ncbi.nlm.nih.gov/37142655","citation_count":24,"is_preprint":false},{"pmid":"21443909","id":"PMC_21443909","title":"Changes in expression of splice cassettes of NMDA receptor GluN1 subunits within the frontal lobe and memory in mice during aging.","date":"2011","source":"Behavioural brain research","url":"https://pubmed.ncbi.nlm.nih.gov/21443909","citation_count":24,"is_preprint":false},{"pmid":"22571986","id":"PMC_22571986","title":"Preweaning sensorimotor deficits and adolescent hypersociability in Grin1 knockdown mice.","date":"2012","source":"Developmental neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/22571986","citation_count":23,"is_preprint":false},{"pmid":"26153703","id":"PMC_26153703","title":"Conformational transitions in the glycine-bound GluN1 NMDA receptor LBD via single-molecule FRET.","date":"2015","source":"Biophysical journal","url":"https://pubmed.ncbi.nlm.nih.gov/26153703","citation_count":22,"is_preprint":false},{"pmid":"25938741","id":"PMC_25938741","title":"Grin1 deletion in CRF neurons sex-dependently enhances fear, sociability, and social stress responsivity.","date":"2015","source":"Psychoneuroendocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/25938741","citation_count":22,"is_preprint":false},{"pmid":"24807818","id":"PMC_24807818","title":"Dietary magnesium restriction reduces amygdala-hypothalamic GluN1 receptor complex levels in mice.","date":"2014","source":"Brain structure & function","url":"https://pubmed.ncbi.nlm.nih.gov/24807818","citation_count":22,"is_preprint":false},{"pmid":"31299220","id":"PMC_31299220","title":"Progressive neuroanatomical changes caused by Grin1 loss-of-function mutation.","date":"2019","source":"Neurobiology of disease","url":"https://pubmed.ncbi.nlm.nih.gov/31299220","citation_count":21,"is_preprint":false},{"pmid":"12707933","id":"PMC_12707933","title":"N-methyl-D-aspartate receptor NR1 subunit gene (GRIN1) in schizophrenia: TDT and case-control analyses.","date":"2003","source":"American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/12707933","citation_count":21,"is_preprint":false},{"pmid":"25045015","id":"PMC_25045015","title":"Transcription factor Sp4 regulates expression of nervous wreck 2 to control NMDAR1 levels and dendrite patterning.","date":"2014","source":"Developmental neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/25045015","citation_count":21,"is_preprint":false},{"pmid":"33965504","id":"PMC_33965504","title":"NMDAR1-Src-Pannexin1 Signal Pathway in the Trigeminal Ganglion Contributed to Orofacial Ectopic Pain Following Inferior Alveolar Nerve Transection.","date":"2021","source":"Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/33965504","citation_count":21,"is_preprint":false},{"pmid":"35245376","id":"PMC_35245376","title":"Deletion of Grin1 in mouse megakaryocytes reveals NMDA receptor role in platelet function and proplatelet formation.","date":"2022","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/35245376","citation_count":20,"is_preprint":false},{"pmid":"22360858","id":"PMC_22360858","title":"Reducing expression of GluN1(0XX) subunit splice variants of the NMDA receptor interferes with spatial reference memory.","date":"2012","source":"Behavioural brain research","url":"https://pubmed.ncbi.nlm.nih.gov/22360858","citation_count":20,"is_preprint":false},{"pmid":"9526033","id":"PMC_9526033","title":"[3H]MK-801 binding and the mRNA for the NMDAR1 subunit of the NMDA receptor are differentially distributed in human and rat forebrain.","date":"1998","source":"Brain research. Molecular brain research","url":"https://pubmed.ncbi.nlm.nih.gov/9526033","citation_count":20,"is_preprint":false},{"pmid":"18729205","id":"PMC_18729205","title":"Dynamic expression patterns of G protein-regulated inducer of neurite outgrowth 1 (GRIN1) and its colocalization with Galphao implicate significant roles of Galphao-GRIN1 signaling in nervous system.","date":"2008","source":"Developmental dynamics : an official publication of the American Association of Anatomists","url":"https://pubmed.ncbi.nlm.nih.gov/18729205","citation_count":19,"is_preprint":false},{"pmid":"28588066","id":"PMC_28588066","title":"Identification of AICP as a GluN2C-Selective N-Methyl-d-Aspartate Receptor Superagonist at the GluN1 Glycine Site.","date":"2017","source":"Molecular pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/28588066","citation_count":19,"is_preprint":false},{"pmid":"35754487","id":"PMC_35754487","title":"Identification of a Subtype-Selective Allosteric Inhibitor of GluN1/GluN3 NMDA Receptors.","date":"2022","source":"Frontiers in pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/35754487","citation_count":18,"is_preprint":false},{"pmid":"7909752","id":"PMC_7909752","title":"Expression of NMDAR1-1a (N598Q)/NMDAR2A receptors results in decreased cell mortality.","date":"1994","source":"European journal of pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/7909752","citation_count":18,"is_preprint":false},{"pmid":"23578394","id":"PMC_23578394","title":"Modal gating of GluN1/GluN2D NMDA receptors.","date":"2013","source":"Neuropharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/23578394","citation_count":17,"is_preprint":false},{"pmid":"27012890","id":"PMC_27012890","title":"GluN1 deletions in D1- and A2A-expressing cell types reveal distinct modes of behavioral regulation.","date":"2016","source":"Neuropharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/27012890","citation_count":16,"is_preprint":false},{"pmid":"39009095","id":"PMC_39009095","title":"TFAP2A is involved in neuropathic pain by regulating Grin1 expression in glial cells of the dorsal root ganglion.","date":"2024","source":"Biochemical pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/39009095","citation_count":16,"is_preprint":false},{"pmid":"34187890","id":"PMC_34187890","title":"Alternative splicing of GluN1 gates glycine site-dependent nonionotropic signaling by NMDAR receptors.","date":"2021","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/34187890","citation_count":16,"is_preprint":false},{"pmid":"26086092","id":"PMC_26086092","title":"Spermidine and Ca(2+), but not Na(+), can permeate NMDA receptors consisting of GluN1 and GluN2A or GluN2B in the presence of Mg(2+).","date":"2015","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/26086092","citation_count":16,"is_preprint":false},{"pmid":"12454527","id":"PMC_12454527","title":"Systematic mutation analysis of the human glutamate receptor, ionotropic, N-methyl-D-aspartate 1 gene(GRIN1) in schizophrenic patients.","date":"2002","source":"Psychiatric genetics","url":"https://pubmed.ncbi.nlm.nih.gov/12454527","citation_count":15,"is_preprint":false},{"pmid":"28277064","id":"PMC_28277064","title":"Inhibition of NMDA receptor function with an anti-GluN1-S2 antibody impairs human platelet function and thrombosis.","date":"2017","source":"Platelets","url":"https://pubmed.ncbi.nlm.nih.gov/28277064","citation_count":15,"is_preprint":false},{"pmid":"29225568","id":"PMC_29225568","title":"Age-Dependent, Subunit Specific Action of Hydrogen Sulfide on GluN1/2A and GluN1/2B NMDA Receptors.","date":"2017","source":"Frontiers in cellular neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/29225568","citation_count":14,"is_preprint":false},{"pmid":"32037472","id":"PMC_32037472","title":"The association between eating behavior and polymorphisms in GRIN2B, GRIK3, GRIA1 and GRIN1 genes in people with type 2 diabetes mellitus.","date":"2020","source":"Molecular biology reports","url":"https://pubmed.ncbi.nlm.nih.gov/32037472","citation_count":14,"is_preprint":false},{"pmid":"25339225","id":"PMC_25339225","title":"The differential contribution of GluN1 and GluN2 to the gating operation of the NMDA receptor channel.","date":"2014","source":"Pflugers Archiv : European journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/25339225","citation_count":14,"is_preprint":false},{"pmid":"31202607","id":"PMC_31202607","title":"Lectins modulate the functional properties of GluN1/GluN3-containing NMDA receptors.","date":"2019","source":"Neuropharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/31202607","citation_count":13,"is_preprint":false},{"pmid":"10837919","id":"PMC_10837919","title":"NMDAR1 isoforms in the rat superior olivary complex and changes after unilateral cochlear ablation.","date":"2000","source":"Brain research. Molecular brain research","url":"https://pubmed.ncbi.nlm.nih.gov/10837919","citation_count":13,"is_preprint":false},{"pmid":"36341805","id":"PMC_36341805","title":"The pathogenic N650K variant in the GluN1 subunit regulates the trafficking, conductance, and pharmacological properties of NMDA receptors.","date":"2022","source":"Neuropharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/36341805","citation_count":13,"is_preprint":false},{"pmid":"37734923","id":"PMC_37734923","title":"GRIN1 variants associated with neurodevelopmental disorders reveal channel gating pathomechanisms.","date":"2023","source":"Epilepsia","url":"https://pubmed.ncbi.nlm.nih.gov/37734923","citation_count":12,"is_preprint":false},{"pmid":"28365212","id":"PMC_28365212","title":"Residues in the GluN1 C-terminal domain control kinetics and pharmacology of GluN1/GluN3A N-methyl-d-aspartate receptors.","date":"2017","source":"Neuropharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/28365212","citation_count":12,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":55370,"output_tokens":13275,"usd":0.182617,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":24884,"output_tokens":4812,"usd":0.12236,"stage2_stop_reason":"end_turn"},"total_usd":0.304977,"stage1_batch_id":"msgbatch_01DUPACZi7AAWwuZiUjseQF4","stage2_batch_id":"msgbatch_018yt7chE3f48PEFtDwtj6AE","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1994,\n      \"finding\": \"NMDAR1 (GluN1) protein localizes predominantly to postsynaptic densities in neurons of the hippocampus, cerebral cortex, and cerebellar cortex, as determined by ultrastructural immunolocalization. The major staining was in postsynaptic densities apposed by unstained presynaptic terminals, indicating GluN1 is a postsynaptic component of NMDA receptor complexes.\",\n      \"method\": \"Light and electron microscope immunocytochemistry with selective anti-peptide antibody on rat nervous system sections\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct subcellular localization by electron microscopy with functional context, replicated across multiple brain regions; foundational localization paper widely confirmed\",\n      \"pmids\": [\"8301357\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1993,\n      \"finding\": \"In PC12 cells, NMDAR1 mRNA is present but little or no NMDAR1 protein is detectable endogenously, and no functional NMDA-gated ion channels are observed; however, transfection with an NMDAR1 expression vector produces detectable protein. This indicates post-transcriptional regulation controls NMDAR1 protein expression.\",\n      \"method\": \"Northern hybridization, PCR, monoclonal antibody immunoblot, calcium imaging, and patch-clamp recording in PC12 cells; transfection rescue experiment\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — multiple orthogonal methods (Northern blot, immunoblot, electrophysiology, calcium imaging, transfection rescue) in a single rigorous study establishing post-transcriptional control\",\n      \"pmids\": [\"8226739\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"Estradiol treatment in ovariectomized rats increases NMDAR1 subunit protein immunofluorescence in CA1 pyramidal cell somata and dendrites without changing NMDAR1 mRNA levels, indicating estradiol modulates NMDA receptor function via post-transcriptional regulation of the GluN1 subunit protein.\",\n      \"method\": \"Confocal laser scanning microscopy for immunofluorescence quantification of NMDAR1 protein; in situ hybridization for NMDAR1 mRNA in rat hippocampal regions\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — two orthogonal methods (protein immunofluorescence quantification + mRNA in situ hybridization) with clear dissociation of protein vs mRNA regulation; single lab but rigorous experimental design\",\n      \"pmids\": [\"8824322\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"After perforant path transection, NMDAR1 mRNA increases throughout the full dendritic extent of dentate gyrus granule cells (including non-denervated segments), whereas increased NMDAR1 protein is restricted to denervated dendritic segments. This demonstrates that NMDAR1 mRNA is transported into dendrites and that local protein synthesis is regulated independently of mRNA transport in response to synaptic reorganization.\",\n      \"method\": \"Quantitative immunofluorescence and in situ hybridization in rat hippocampus at 2, 5, and 9 days post-lesion\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — two orthogonal methods (immunofluorescence protein quantification + in situ hybridization mRNA quantification) with clear dissociation at subcellular compartment level\",\n      \"pmids\": [\"9045729\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Cell-type-specific transcription of the NMDAR1 gene is controlled by the neuron-restrictive silencer element (NRSE/NRSF) and by single-stranded DNA-binding proteins (SBPs) interacting with a GC-rich/Sp1-containing proximal promoter region. The SBPC2 complex (enriched in neurons) correlates with higher promoter activity; NGF treatment shifts the ratio from SBPC1 to SBPC2 in PC12 cells, suggesting a mechanism for NGF-regulated NMDAR1 transcription.\",\n      \"method\": \"Deletion analysis of NMDAR1 promoter in C6, HeLa, and PC12 cells; EMSA with nuclear proteins; UV cross-linking; competition experiments; cotransfection with single-stranded DNA\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — multiple orthogonal methods (promoter deletion, EMSA, UV cross-linking, cotransfection) in a single study, single lab\",\n      \"pmids\": [\"9422773\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"In nNOS-positive neurons of the neostriatum, neocortex, and hippocampus, the NMDAR1 subunit is present but specifically lacks the C1 splice cassette and preferentially contains the C2' terminus (generated when the C2 segment is absent), revealing that nNOS neurons express a distinct NMDAR1 isoform profile compared to surrounding neurons.\",\n      \"method\": \"Dual-label immunofluorescence with confocal microscopy using antibodies to nNOS and NMDAR1 cassettes (N1, C1, C2) in rat forebrain\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal dual-label immunofluorescence with multiple antibodies recognizing distinct splice cassettes; single lab, single method type but uses multiple probes\",\n      \"pmids\": [\"9464997\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"The σ-1 receptor (Sig1R) binds directly and specifically to the GluN1 subunit within GluN1/GluN2A NMDA receptor heterotetramers, but not to GluN2A. This was shown by AFM imaging of subunit arrangement angles, co-isolation experiments, and in situ proximity ligation assays in intact cells. The Sig1R C-terminus faces extracellularly.\",\n      \"method\": \"Atomic force microscopy (AFM) imaging of receptor complexes; co-immunoprecipitation of Sig1R with GluN1 but not GluN2A; proximity ligation assay in intact cells\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (AFM imaging with angle analysis, reciprocal co-IP, in situ PLA in intact cells) in a single rigorous study\",\n      \"pmids\": [\"24227730\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Functional GluN1/GluN2A NMDA receptors adopt an alternating 1/2/1/2 subunit arrangement (like subunits diagonal to one another). In this arrangement, GluN1 subunits occupy a 'proximal' position closer to the central pore axis than GluN2 subunits. Immature (intracellular) and mature (plasma-membrane-inserted) receptor pools can adopt different subunit arrangements.\",\n      \"method\": \"Electrophysiology (disulfide cross-linking between subunits combined with functional recording) and structural analysis based on AMPA receptor crystal structure homology\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — electrophysiology combined with disulfide cross-linking and structural analysis; multiple approaches converging on same conclusion in a single study\",\n      \"pmids\": [\"22493736\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"The GluN1 N-terminal domain (NTD) is neither static nor functionally silent. Perturbing GluN1 NTD conformation affects receptor gating and pharmacological properties. GluN1 NTD undergoes hinge-bending, twisting, and untwisting motions forming new intra- and intersubunit contacts, and acts in trans with GluN2 NTD to influence glutamate binding (but not GluN1 glycine binding).\",\n      \"method\": \"Single-molecule FRET, mutagenesis, electrophysiology of recombinant NMDARs; conformational perturbation of GluN1 NTD with designed mutations\",\n      \"journal\": \"Nature structural & molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — smFRET structural dynamics combined with mutagenesis and electrophysiology; multiple orthogonal methods; single lab\",\n      \"pmids\": [\"23454977\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Crystal structures of the GluN1 ligand-binding domain (LBD) in the apo state reveal an open-cleft conformation. Computed free energy landscapes show GluN1 apo-state LBDs sample closed-cleft conformations via conformational selection (rather than induced-fit) for glycine binding, with a spectrum of hinge bending, rocking, twisting, and sweeping motions distinct from GluN2A and GluN3A LBDs.\",\n      \"method\": \"X-ray crystallography of GluN1 LBD; computational conformational free energy landscapes; principal component analysis\",\n      \"journal\": \"Structure\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure combined with computational analysis; rigorous structural and dynamic characterization; single lab\",\n      \"pmids\": [\"23972471\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Crystal structure of the GluN1 ligand-binding domain in complex with the competitive antagonist TK40 reveals that TK40 binds to the orthosteric glycine-binding site of GluN1 with an imino acetamido group acting as an α-amino acid bioisostere. Schild analysis confirmed competitive antagonism with Kb of 21–63 nM at GluN1/GluN2A-D, with >100-fold selectivity over GluN3-containing receptors.\",\n      \"method\": \"X-ray crystallography of GluN1 LBD–TK40 complex; Schild analysis; radioligand binding on rat brain membranes and purified GluN1 LBD; virtual screening\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure, functional pharmacological characterization, and radioligand binding; multiple orthogonal methods; clear mechanistic insight\",\n      \"pmids\": [\"24072709\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"The GluN1 exon 5-encoded N1 cassette in the amino-terminal domain is a key determinant of GluN1/GluN2D receptor function. GluN1-1b (exon 5-containing) receptors deactivate ~3-fold faster and have ~2-fold higher open probability than GluN1-1a receptors. Residue Lys211 in GluN1-1b is identified as a critical determinant of exon 5 control of deactivation and glutamate potency.\",\n      \"method\": \"Whole-cell and single-channel electrophysiology of recombinant GluN1/GluN2D receptors with GluN1 splice variants; site-directed mutagenesis; kinetic modeling\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstituted recombinant receptors, mutagenesis, multiple electrophysiological readouts, and kinetic modeling in a single rigorous study\",\n      \"pmids\": [\"22641781\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Intrasubunit disulfide bonds that constrain the M3-S2 linker in either the GluN1 or GluN2A subunit equally impair NMDA receptor pore opening, demonstrating that conformational freedom of the LBD-TMD linkers in both subunits is required and that the pore-opening mechanism involves tightly coupled intrasubunit dynamics at LBD-TMD linkers across all four subunits.\",\n      \"method\": \"Disulfide bond engineering (intrasubunit bonds between M3-S2 and S2-M4 linkers) in GluN1 or GluN2A; whole-cell and single-channel electrophysiology\",\n      \"journal\": \"The Journal of general physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — engineered disulfide constraints with electrophysiological validation; clean gain-of-constraint approach with single-channel analysis; single lab\",\n      \"pmids\": [\"21746848\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"The GluN1 ligand-binding domain exists in multiple conformations even when glycine is bound, transitioning reversibly among states corresponding to different cleft widths on long timescales (much longer than channel opening). The LBD proceeds primarily from one adjacent smFRET state to the next, consistent with a sequential cleft-opening/closing mechanism.\",\n      \"method\": \"Single-molecule FRET on purified GluN1 LBD with glycine bound; step-transition and state-identification algorithm; denaturant shift experiments\",\n      \"journal\": \"Biophysical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — single-molecule FRET with reversibility confirmation and model-free state analysis; single lab but multiple orthogonal validations within study\",\n      \"pmids\": [\"26153703\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Concurrent stimulation of D1 dopamine receptors (D1R) and NMDA receptors drives formation of D1R/GluN1 complexes. Preventing D1R/GluN1 association with a cell-permeable TAT-GluN1C1 peptide leaves individual D1R and NMDAR signaling intact but blocks D1R-mediated facilitation of NMDAR calcium influx and ERK activation. D1R/GluN1 complexes control D1R-dependent enhancement of NMDAR currents and LTP in D1R-MSN, and are required for cocaine behavioral sensitization.\",\n      \"method\": \"Co-immunoprecipitation of endogenous D1R and GluN1; cell-permeable blocking peptide (TAT-GluN1C1); calcium imaging; ERK phosphorylation assay; whole-cell electrophysiology in striatal slices; in vivo behavioral sensitization\",\n      \"journal\": \"Molecular psychiatry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (co-IP, peptide disruption, Ca2+ imaging, ERK signaling, electrophysiology, behavior); all converge on same conclusion; single lab but comprehensive\",\n      \"pmids\": [\"25070539\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Neurofilament light (NFL) protein interacts with GluN1 (NMDAR1) at synapses. NFL knockout reduces dendritic spines and GluN1 protein levels, elevates ubiquitin-dependent turnover of GluN1, increases hippocampal glutamate (by MRS), and depresses LTP. NFL+/- mice (at levels matching schizophrenia) show milder but similar NMDAR-related synaptic and behavioral deficits, indicating NFL stabilizes GluN1 at synapses.\",\n      \"method\": \"Co-immunoprecipitation of NFL and GluN1; NFL knockout and heterozygous mouse models; immunofluorescence; MRS; electrophysiology (LTP); behavioral tests\",\n      \"journal\": \"Translational psychiatry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal co-IP plus loss-of-function mouse genetics with multiple orthogonal functional readouts (protein levels, ubiquitination, MRS, LTP, behavior)\",\n      \"pmids\": [\"30143609\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Triheteromeric GluN1/GluN2A/GluN2B NMDA receptors have glutamate deactivation kinetics and pharmacological sensitivity to subunit-selective antagonists (ifenprodil, CP-101,606, TCN-201) and Zn2+ that are distinct from diheteromeric GluN1/GluN2A and GluN1/GluN2B receptors. The ifenprodil binding site geometry differs in triheteromers compared to GluN1/GluN2B diheteromers.\",\n      \"method\": \"Selective cell-surface expression of recombinant triheteromeric receptors using a dominant-negative subunit strategy; whole-cell voltage-clamp electrophysiology; pharmacological characterization\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — novel expression strategy to isolate triheteromers, combined with comprehensive electrophysiology and pharmacology; rigorous controls; important mechanistic paper\",\n      \"pmids\": [\"24607230\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"GluN1/GluN3A receptors are functionally expressed in adult mouse medial habenula neurons and are activated by glycine alone (not glutamate). Glial cells tune neuronal activity via GluN1/GluN3A receptors; reducing GluN1/GluN3A levels in the MHb prevented place-aversion conditioning, demonstrating a role for these glycine-gated NMDAR subtype in control of aversive behavior.\",\n      \"method\": \"Electrophysiology in adult mouse brain slices with CGP-78608 to unmask GluN1/GluN3A currents; viral knockdown in medial habenula; conditioned place aversion behavioral test\",\n      \"journal\": \"Science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — electrophysiology in native adult tissue combined with in vivo loss-of-function and behavioral readout; landmark finding of native GluN1/GluN3A function\",\n      \"pmids\": [\"31601771\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"GluN1/GluN3A receptors can be unmasked by CGP-78608 (which blocks GluN1 glycine site to prevent desensitization) and modulated by an endogenous GluN3A disulfide bond that controls redox sensitivity, agonist sensitivity, and gating kinetics. Under reducing conditions, ambient glycine is sufficient to tonically activate GluN1/GluN3A receptors in hippocampal neurons.\",\n      \"method\": \"Whole-cell voltage-clamp electrophysiology in HEK cells and hippocampal slices; redox manipulation; pharmacology with CGP-78608\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — reconstituted recombinant receptors plus native tissue electrophysiology; pharmacological and redox mechanistic dissection; multiple orthogonal approaches\",\n      \"pmids\": [\"30425244\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"GluN1 alternative splicing controls nonionotropic (metabotropic) signaling by NMDARs. Glycine priming (binding to GluN1 glycine site without channel opening) induces receptor internalization only in GluN1 isoforms lacking the N1 cassette (exon 5); N1-containing isoforms block this nonionotropic signaling. C-terminal cassettes (C1, C2, C2') each permit glycine signaling. This was confirmed in CA1 pyramidal neurons (glycine priming present) vs. interneurons (glycine priming absent due to N1 expression).\",\n      \"method\": \"Recombinant receptor electrophysiology; engineered mouse knockin lines (GluN1 obligatorily containing or lacking N1 cassette); NMDAR internalization assays; electrophysiology in hippocampal CA1 pyramidal neurons and interneurons\",\n      \"journal\": \"Proceedings of the National Academy of Sciences\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — recombinant + in vivo knockin models + native neuron electrophysiology; multiple orthogonal approaches; single lab but comprehensive\",\n      \"pmids\": [\"34187890\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"GluN1 exon 5 (N1 cassette) inclusion/exclusion controls LTP magnitude and spatial memory performance. Mice lacking the N1 cassette (GluN1a) show significantly enhanced hippocampal LTP and faster learning with better spatial memory compared to mice obligatorily expressing exon 5 (GluN1b), despite no differences in basal synaptic transmission.\",\n      \"method\": \"Generation of GluN1a (exon 5 knockout) and GluN1b (obligatory exon 5 expression) knockin mice; hippocampal slice LTP recordings; Morris water maze; novel object recognition behavioral tests\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vivo genetic knockin models combined with electrophysiology and multiple behavioral paradigms; rigorous controls and comparison between two engineered lines\",\n      \"pmids\": [\"31875540\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Cryo-EM structures of human GluN1-GluN2A NMDA receptor at ~4 Å reveal: competitive antagonists bound at GluN1 and GluN2A LBDs; a positive allosteric modulator shortens the distance between LBDs and TMD, stretching the gate open; the 'foot-in-the-door' blocker 9-aminoacridine binds within the LBD-TMD linker region (not the conventional TMD vestibule), providing molecular insights into crosstalk between LBDs and TMD during activation, inhibition, and allosteric transitions.\",\n      \"method\": \"Cryo-electron microscopy of full-length human GluN1-GluN2A NMDA receptor in complex with distinct ligands/modulators\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — high-resolution cryo-EM structures in multiple ligand states; single lab but structural evidence directly reveals mechanism; landmark structural paper\",\n      \"pmids\": [\"34186027\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Cryo-EM structures of human GluN1-GluN2C and GluN1-GluN2D NMDARs reveal unique inter-subunit and domain arrangements of GluN2C NMDARs, distinct from GluN2D. The GluN2C PAM (PYD-106) binding pocket is defined by these unique arrangements. Triheteromeric GluN1-2A-2C structure is also resolved.\",\n      \"method\": \"Single-particle cryo-electron microscopy of agonist-bound human GluN1-GluN2C, GluN1-GluN2A-GluN2C (triheteromeric), and GluN1-GluN2D receptors\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — multiple cryo-EM structures of distinct GluN2 subtypes; direct structural determination of allosteric modulator binding pocket; single lab but rigorous structural study\",\n      \"pmids\": [\"36309015\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Cryo-EM structures of GluN1/GluN3A NMDA receptors bound to antagonist (CNQX) and agonist (glycine) reveal a 1-3-1-3 heterotetrameric subunit arrangement. Glycine binding induces an unprecedented orientation shift in GluN3A subunits. Site-directed disruption of the unique glycine-bound subunit interface mitigates desensitization, establishing a structural basis for GluN3A-specific desensitization.\",\n      \"method\": \"Cryo-electron microscopy of GluN1/GluN3A NMDA receptors in agonist- and antagonist-bound states; site-directed mutagenesis of subunit interface with functional electrophysiology\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — cryo-EM structures in two functional states combined with mutagenesis validation; defines 1-3-1-3 arrangement and desensitization mechanism\",\n      \"pmids\": [\"38598639\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Specificity protein 4 (Sp4) functionally regulates transcription of GluN1, GluN2A, and GluN2B NMDA receptor subunit genes, operating complementarily and in parallel with NRF-1 and NRF-2. Sp1 and Sp3 do not regulate these subunits. Sp4 operates in a complementary and concurrent manner with NRF-1/NRF-2 to couple energy metabolism with neuronal activity at the transcriptional level.\",\n      \"method\": \"Promoter-reporter assays; ChIP; EMSA; siRNA knockdown; transfection in neurons and non-neuronal cells\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple transcriptional methods (promoter-reporter, ChIP, EMSA, siRNA) in a single lab study\",\n      \"pmids\": [\"23871830\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Sp4 transcription factor activates transcription of Nwk2 (Nervous Wreck 2/Fchsd1), which in turn mediates Sp4-dependent regulation of cell surface expression of GluN1 (NR1) and dendrite patterning. Acute Sp4 depletion reduces surface but not total NR1; this is rescued by Nwk2 expression. Identifies a Sp4-Nwk2-NR1 pathway regulating NMDAR trafficking and neuronal morphogenesis.\",\n      \"method\": \"Promoter-luciferase reporter assays; siRNA knockdown of Sp4 and Nwk2 in cerebellar granule neurons; rescue experiments; surface vs. total NR1 quantification by immunostaining; dendrite morphology analysis\",\n      \"journal\": \"Developmental neurobiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reporter assays, knockdown with defined phenotypic readouts (surface NR1, dendrite number), rescue experiment; single lab\",\n      \"pmids\": [\"25045015\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"KCTD13 (a substrate adaptor for Cullin3-E3 ubiquitin ligase) facilitates lysine-48-linked polyubiquitination of GluN1 at lysine 860, targeting it for degradation via the ubiquitin-proteasome pathway. KCTD13 knockdown in hippocampus reduces surface glutamate receptor expression, impairs glutamate synaptic transmission, and enhances seizure susceptibility; overexpression has the opposite effect.\",\n      \"method\": \"Co-immunoprecipitation to identify GluN1 as KCTD13 substrate; ubiquitination assay specifying K48-linkage; site-directed mutagenesis to identify K860 ubiquitination site; hippocampal knockdown/overexpression by viral vectors; electrophysiology; seizure susceptibility assays in TLE mouse model\",\n      \"journal\": \"Cell death and differentiation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — identifies writer (KCTD13/Cullin3), modification (K48 ubiquitination), site (K860), and functional consequence (proteasomal degradation, altered surface expression, seizure threshold); multiple orthogonal methods\",\n      \"pmids\": [\"37142655\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"De novo GRIN1 mutations clustering in transmembrane segments cause loss of NMDA receptor channel function with a dominant-negative effect (heterozygous mutations in transmembrane domains). Homozygous GRIN1 mutations (missense and truncation) also cause severe neurodevelopmental phenotypes. Functional characterization in Xenopus oocytes confirmed loss of channel function of varying severity.\",\n      \"method\": \"Two-electrode voltage-clamp in Xenopus oocytes expressing mutant GluN1 subunits; structural mapping of mutations onto 3D models; clinical genetics\",\n      \"journal\": \"Neurology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional electrophysiology in Xenopus oocytes for multiple variants; single expression system; mechanistic classification as dominant-negative loss-of-function\",\n      \"pmids\": [\"27164704\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"The de novo GluN1-G620R mutation causes ~2-fold decrease in glutamate and glycine potency, strong decrease in Mg2+ block sensitivity, and significant reduction of current responses; GluN1-G620R/GluN2B complexes show significantly reduced delivery to the cell surface. This combination of trafficking defect and functional loss-of-function underlies the patient's neurodevelopmental phenotype.\",\n      \"method\": \"Electrophysiology (whole-cell patch-clamp) of GluN1-G620R/GluN2A and GluN1-G620R/GluN2B in HEK cells; surface trafficking assay (cell-surface biotinylation/immunofluorescence)\",\n      \"journal\": \"Journal of human genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — electrophysiology combined with trafficking assay; two subunit combinations tested; clear mechanistic dissection of a pathogenic variant\",\n      \"pmids\": [\"28228639\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"The recurrent de novo GluN1-M641I variant causes enhanced agonist potency and reduced Mg2+ block of NMDARs. These gain-of-function properties confer increased sensitivity to NMDAR channel blockers memantine, ketamine, and dextromethorphan compared to wild-type. Addition of memantine to the patient's treatment significantly reduced seizure burden.\",\n      \"method\": \"Two-electrode voltage-clamp in Xenopus oocytes and whole-cell recording in HEK cells; beta-lactamase reporter assay for surface expression; FDA-approved drug screening\",\n      \"journal\": \"Annals of clinical and translational neurology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — electrophysiology in two expression systems plus drug screening with patient-level clinical validation; gain-of-function mechanism established\",\n      \"pmids\": [\"34227748\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"GRIN1 mutations associated with polymicrogyria (clustering in the S2 ligand-binding domain region and adjacent M3 helix) significantly alter receptor activity in vitro. Three mutations increased agonist potency while one reduced proton inhibition—a gain-of-function profile distinct from loss-of-function seen in previous GRIN1 mutations.\",\n      \"method\": \"Two-electrode voltage-clamp and whole-cell voltage-clamp electrophysiology of mutant GluN1-containing receptors in Xenopus oocytes and transfected cells; whole-exome sequencing\",\n      \"journal\": \"Brain\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — electrophysiology in two expression systems characterizing multiple variants; mechanistic gain-of-function classification with agonist potency and proton inhibition assays\",\n      \"pmids\": [\"29365063\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Protocadherin 7 (PCDH7) interacts with the N-terminal domain of GluN1 (identified by unbiased screen of ~1,500 transmembrane proteins using purified GluN1-NTD bait). PCDH7 overexpression reduces synaptic NMDAR currents and induces dendritic structural changes; PCDH7 knockdown has opposing effects on dendritic morphology.\",\n      \"method\": \"Protein interaction screen using purified GluN1-NTD as bait against ~1,500 transmembrane proteins; primary neuron overexpression and knockdown; whole-cell electrophysiology; dendritic morphology analysis\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — unbiased interaction screen + functional validation in neurons with electrophysiology and morphology readouts; single lab; interaction binding confirmed but mechanism of NMDAR modulation not fully resolved\",\n      \"pmids\": [\"32616769\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Structural features of the glycine-binding site in GluN1 (and GluN3A) correlate with forward trafficking of NMDARs to the cell surface. Mutations in the GluN1 glycine-binding site alter surface delivery in both cell lines and primary hippocampal neurons, establishing that the glycine-binding site structure regulates receptor trafficking beyond just ligand binding.\",\n      \"method\": \"Site-directed mutagenesis of glycine-binding site residues; immunofluorescence and flow cytometry-based surface expression assays in HEK cells and primary rat hippocampal neurons\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — mutagenesis combined with surface expression quantification in two cell systems; single lab; clear mechanistic link between binding site structure and trafficking\",\n      \"pmids\": [\"31444392\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"The pathogenic GluN1-N650K variant increases surface expression of GluN1/GluN2A and GluN1/GluN2B receptors (but not GluN1/GluN3A), enhances agonist potency, decreases conductance and open probability, and alters sensitivity to channel blockers memantine and ketamine. The K650 residue is located in the pore region; GluN1-N650K/GluN2B does not form functional receptors.\",\n      \"method\": \"Microscopy-based surface expression assays in HEK cells and hippocampal neurons; whole-cell patch-clamp electrophysiology; pharmacological profiling; excitotoxicity assays\",\n      \"journal\": \"Neuropharmacology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — electrophysiology combined with trafficking assays and pharmacology in two cell systems; comprehensive mechanistic characterization of a single pathogenic variant\",\n      \"pmids\": [\"36341805\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"In mice with selective Grin1 deletion in CRF neurons (especially in the CeA), fear memory acquisition and retention are enhanced without affecting fear extinction, exploration, or pain sensitivity. Amygdala Gria1 and Creb1 were elevated after fear conditioning in mutants, linking NMDAR function in CRF-CeA neurons to fear memory circuitry via AMPAR and CREB pathways.\",\n      \"method\": \"CRF-Cre × floxed Grin1 mice; CeA-targeted lentiviral Cre delivery; fear conditioning; RT-PCR for Gria1 and Creb1\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — cell-type-specific genetic knockout with behavioral readouts and molecular correlates; single lab; pathway placement via epistasis\",\n      \"pmids\": [\"25340785\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Platelet lineage-specific knockout of Grin1 (Pf4-Grin1-/- mice) causes defects in megakaryopoiesis, thrombopoiesis, and platelet function: reduced platelet counts, impaired platelet activation and spreading, reduced Ca2+ responses, and prolonged bleeding time. GluN1 deletion impairs F-actin and α-tubulin reorganization in megakaryocytes and reduces proplatelet formation, indicating NMDAR regulates PPF through MK-ECM interaction and cytoskeletal reorganization.\",\n      \"method\": \"Cre-loxP platelet lineage-specific Grin1 knockout; platelet function assays; calcium imaging; actin/tubulin immunofluorescence; colony and proplatelet formation assays; tail bleeding time; immune thrombocytopenia model\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vivo genetic model with comprehensive functional readouts (platelet counts, Ca2+ signaling, cytoskeletal analysis, bleeding time, colony formation); multiple orthogonal methods\",\n      \"pmids\": [\"35245376\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Anti-GluN1-S2 antibody (targeting the glycine-binding region of GluN1) inhibits human platelet activation, aggregation, and thrombus formation. The antibody epitope maps to α-helix H within the GluN1 glycine-binding clamshell; computational modeling predicts antibody binding impairs channel opening. This establishes GluN1 glycine-binding site function in platelet NMDARs that regulate thrombus formation.\",\n      \"method\": \"Platelet aggregation assays; thrombus formation under flow; epitope mapping by mutagenesis; crystal structure-based computational modeling; rat vaccination model\",\n      \"journal\": \"Platelets\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional antibody inhibition assays with epitope mapping and structural modeling; single lab; mechanism inferred from antibody binding site\",\n      \"pmids\": [\"28277064\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Transcription factor TFAP2A positively regulates Grin1 gene expression, as confirmed by dual-luciferase reporter assay. In satellite glial cells of the DRG, Tfap2a knockdown reduces Grin1 expression; Grin1 knockdown in DRG alleviates neuropathic pain. Tfap2a siRNA also reduces NMDA-induced proinflammatory cytokine upregulation in primary SGCs.\",\n      \"method\": \"Dual-luciferase reporter assay for TFAP2A regulation of Grin1 promoter; siRNA knockdown in vivo (intrathecal) and in primary SGCs; RT-PCR and immunostaining; pain behavioral tests\",\n      \"journal\": \"Biochemical pharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reporter assay establishes transcriptional regulation; in vivo knockdown with behavioral readout; in vitro cellular confirmation; single lab\",\n      \"pmids\": [\"39009095\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Properties of triheteromeric GluN1/GluN1-1a/GluN1-1b/GluN2A and GluN1-1a/GluN1-1b/GluN2B receptors are intermediate between diheteromeric GluN1-1a/GluN1-1a/GluN2 and GluN1-1b/GluN1-1b/GluN2 receptors. A single copy of GluN3 pore residues strongly attenuates Mg2+ block and Ca2+ permeability; GluN1 and GluN2 pore residues contribute asymmetrically to Mg2+ block.\",\n      \"method\": \"FRET and FLIM to confirm triheteromeric assembly; selective surface expression strategy; whole-cell electrophysiology; pharmacological characterization; site-directed mutagenesis of pore residues\",\n      \"journal\": \"Molecular pharmacology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — FRET/FLIM for assembly confirmation + electrophysiology + mutagenesis; rigorous demonstration of triheteromeric assembly and functional characterization\",\n      \"pmids\": [\"29483146\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"GluN2 subunit is most likely directly responsible for the NMDA channel activation gate, while GluN1 assumes a role of more global control over gating conformational changes in GluN2. Specific mutations in the A7 residue of the SYTANLAAF motif in GluN1 (but not GluN2) result in channels with markedly enhanced affinity for both glycine and NMDA and can be activated by NMDA alone, suggesting GluN1 globally regulates GluN2 gating via this intersubunit interaction.\",\n      \"method\": \"Whole-cell patch-clamp electrophysiology; site-directed mutagenesis of SYTANLAAF motif A7 residue in GluN1 and GluN2; kinetic analysis of binding and unbinding rates\",\n      \"journal\": \"Pflugers Archiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — mutagenesis combined with detailed kinetic electrophysiology; single lab; mechanistic dissection of GluN1 vs GluN2 contributions to gating\",\n      \"pmids\": [\"25339225\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"The human GRIN1 gene is composed of 21 exons distributed over ~31 kb on chromosome 9q34.3-qter. Exons 4, 20, and 21 are subject to alternative splicing (identical in sequence to rat alternatively spliced exons), indicating all eight NMDAR1 isoforms found in rat are also expressed in human brain. The promoter contains two copies of the even-skipped homeodomain recognition sequence, implicating homeobox protein control of developmental expression.\",\n      \"method\": \"Cosmid cloning and sequencing of human GRIN1 gene; FISH mapping to chromosome 9q34.3-qter; computer analysis of pre-mRNA secondary structure and promoter elements\",\n      \"journal\": \"Gene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct gene structure determination by sequencing and FISH; promoter element identification by sequence analysis; single lab; structural genomics establishes basis for splice isoform diversity\",\n      \"pmids\": [\"7622053\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Protons (extracellular acidification) potentiate GluN1/GluN3A receptor currents with half-maximal effect in the physiological pH range by slowing desensitization and accelerating recovery from desensitization. This modulation is mediated by residues at the heterodimer interface of the ligand-binding domain (GluN1 LBD interface with GluN3A).\",\n      \"method\": \"Whole-cell voltage-clamp of recombinant GluN1/GluN3A in HEK cells; site-directed mutagenesis of LBD interface residues; rapid solution exchange\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — mutagenesis identifies critical residues + electrophysiology characterizes mechanism; single lab; specific mechanistic assignment to LBD heterodimer interface\",\n      \"pmids\": [\"27000430\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"GluN1 C-terminal alternatively spliced cassettes control steady-state activity level and pharmacological sensitivity (to zinc and protons) of GluN1/GluN3A receptors. Phosphorylation status of sites specific to certain GluN1 variants also modulates GluN1/GluN3A channel activity, indicating C-terminal domain splicing confers cell-specific and activity-dependent regulation.\",\n      \"method\": \"Whole-cell electrophysiology of recombinant GluN1 splice variants assembled with GluN3A in HEK293 cells; pharmacological characterization; phosphorylation state manipulation\",\n      \"journal\": \"Neuropharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — electrophysiology with defined splice variants and pharmacological tools; single lab; establishes role of C-terminal domain in receptor regulation\",\n      \"pmids\": [\"28365212\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"The GluN1(Y668H) variant (associated with neurodevelopmental disorder) severely impairs surface expression of GluN1/GluN2A receptors, enhances sensitivity to glycine and glutamate by an order of magnitude, impairs Mg2+ block, reduces blocker (memantine/ketamine/MK-801) potency, and allows activation by either agonist alone. Single-channel recordings show this variant opens to multiple conductance levels more frequently than wild-type, revealing Y668 as a critical locus coupling receptor gating to ion channel conductance.\",\n      \"method\": \"Whole-cell and single-channel patch-clamp electrophysiology in HEK293 cells; surface expression assay; pharmacological profiling; primary hippocampal neuron recordings\",\n      \"journal\": \"Epilepsia\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — single-channel + whole-cell electrophysiology + surface expression assays; identifies specific structural locus (Y668) coupling gating to conductance; multiple readouts in single study\",\n      \"pmids\": [\"37734923\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"EU1180-438, a negative allosteric modulator selective for GluN1/GluN3 receptors over GluN1/GluN2 NMDARs, inhibits GluN1/GluN3A currents in a voltage-independent, glycine concentration-independent manner. Site-directed mutagenesis identifies structural determinants of EU1180-438 activity near a short pre-M1 helix of GluN3 subunits. Non-stationary fluctuation analysis estimates native GluN1/GluN3A channel conductance at ~6.1 pS.\",\n      \"method\": \"Whole-cell electrophysiology of recombinant GluN1/GluN3 and GluN1/GluN2 receptors in HEK cells; native hippocampal CA1 neuron recordings; site-directed mutagenesis; non-stationary fluctuation analysis\",\n      \"journal\": \"Neuropharmacology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — mutagenesis identifies binding site + functional characterization in recombinant and native systems + biophysical single-channel analysis; multiple orthogonal approaches\",\n      \"pmids\": [\"32389749\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"α2δ-1 (a voltage-gated calcium channel regulatory subunit) interacts with NMDAR1 to form a complex that regulates NMDAR expression in the hypothalamus. Co-immunoprecipitation confirmed α2δ-1/NMDAR1 interaction. In α2δ-1 gene-knockout PC12 cells, quercetin had no effect on NMDAR1 expression, demonstrating the functional dependence of NMDAR1 regulation on α2δ-1.\",\n      \"method\": \"Co-immunoprecipitation; Western blot; immunofluorescence; α2δ-1 gene knockout in PC12 cells with NMDAR1 expression measurement; CUMS rat model\",\n      \"journal\": \"CNS neuroscience & therapeutics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP of interaction combined with functional gene-knockout validation; single lab; shows α2δ-1 dependence of NMDAR1 regulation\",\n      \"pmids\": [\"38615365\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"GluN1 (GRIN1) is the obligatory glycine-binding subunit of all NMDA receptor complexes, assembling as two GluN1 subunits with two GluN2 (or GluN3) subunits in an alternating 1/2/1/2 tetrameric arrangement at postsynaptic densities; the GluN1 N-terminal domain undergoes dynamic conformational changes that allosterically regulate GluN2-dependent gating, its ligand-binding domain (LBD) uses a conformational selection mechanism for glycine and undergoes multiple equilibrium conformations even when occupied, and its exon-5-encoded N1 cassette and C-terminal splice cassettes tune channel kinetics, open probability, nonionotropic (glycine-only) signaling, and allosteric modulation; GluN1 expression is controlled post-transcriptionally by mechanisms including NFL-dependent stabilization against ubiquitin-proteasomal degradation (with KCTD13 as an E3 adaptor ubiquitinating K860), transcriptionally by Sp4 (via Nwk2) and TFAP2A, and the receptor complex is directly bound by σ-1 receptor (at GluN1) and forms functional complexes with D1 dopamine receptors and α2δ-1 that regulate calcium influx, ERK signaling, and plasticity; beyond canonical glutamatergic synapses, GluN1/GluN3A receptors activated by glycine alone operate in adult brain regions (medial habenula, hippocampal CA1 neurons) to control aversive behavior and excitability, and NMDA receptors containing GluN1 are also functional in megakaryocytes where they regulate proplatelet formation through Ca2+ signaling and cytoskeletal reorganization.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"GRIN1 encodes GluN1, the obligatory subunit of NMDA receptor complexes localized to postsynaptic densities of neurons throughout the hippocampus, cortex, and cerebellum [#0]. Functional receptors assemble as alternating 1/2/1/2 tetramers in which GluN1 occupies the pore-proximal position relative to GluN2 [#7], and GluN1 also forms 1-3-1-3 arrangements with GluN3A [#23]. Within the complex GluN1 supplies the glycine-binding ligand-binding domain (LBD), whose apo state samples closed-cleft conformations by conformational selection and continues to transition among multiple cleft widths even when glycine is bound [#9, #13]; its N-terminal domain is conformationally dynamic and acts allosterically in trans to influence GluN2-dependent glutamate binding and gating [#8]. GluN1 exerts global control over channel gating—mutations in its SYTANLAAF gating motif permit activation by NMDA alone [#39]—and conformational freedom of its LBD-TMD linkers is required for pore opening, as revealed by cryo-EM structures defining how LBD-TMD crosstalk drives activation, allosteric potentiation, and channel block [#12, #21]. GluN1 alternative splicing tunes receptor behavior: the exon-5 N1 cassette accelerates deactivation, raises open probability, gates nonionotropic glycine-primed internalization, and sets the magnitude of hippocampal LTP and spatial learning [#11, #19, #20], while C-terminal cassettes regulate GluN1/GluN3A activity and pharmacology [#42]. GluN1/GluN3A receptors gated by glycine alone operate in adult medial habenula and CA1 neurons to control aversive behavior and excitability [#17, #18]. GluN1 abundance and surface delivery are controlled post-transcriptionally—neurofilament light stabilizes GluN1 against ubiquitin-proteasomal turnover [#15], the Cullin3 adaptor KCTD13 drives K48-linked polyubiquitination at K860 to set surface receptor levels and seizure threshold [#26]—and transcriptionally by Sp4 (via Nwk2) and TFAP2A [#24, #25, #37]. GluN1 is directly bound by the σ-1 receptor, partners with D1 dopamine receptors to couple to ERK signaling and plasticity, and associates with α2δ-1, PCDH7, and protons that modulate gating and trafficking [#6, #14, #45, #31, #41]. De novo GRIN1 mutations cause severe neurodevelopmental disorders through either dominant-negative loss of channel function or gain-of-function alterations in agonist potency, Mg2+ block, and trafficking [#27, #29, #30, #43]. Beyond the nervous system, GluN1-containing NMDA receptors in megakaryocytes regulate proplatelet formation through Ca2+ signaling and cytoskeletal reorganization [#35, #36].\",\n  \"teleology\": [\n    {\n      \"year\": 1994,\n      \"claim\": \"Establishing where GluN1 acts answered whether it is a synaptic receptor component, placing it at the postsynaptic membrane of central neurons.\",\n      \"evidence\": \"Ultrastructural immunocytochemistry on rat nervous system sections\",\n      \"pmids\": [\"8301357\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve subunit stoichiometry or partner subunits\", \"No functional measurement at characterized synapses\"]\n    },\n    {\n      \"year\": 1995,\n      \"claim\": \"Defining the human GRIN1 gene structure established the genomic basis for the eight splice isoforms and implicated developmental promoter control.\",\n      \"evidence\": \"Cosmid cloning, sequencing, and FISH mapping of human GRIN1\",\n      \"pmids\": [\"7622053\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequences of individual isoforms not tested\", \"Homeodomain promoter control inferred from sequence, not assayed\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Identifying NRSE/NRSF, single-stranded DNA-binding proteins, and later Sp4/Nwk2 and TFAP2A answered how GluN1 transcription is restricted to neurons and coupled to activity and signaling.\",\n      \"evidence\": \"Promoter deletion, EMSA, ChIP, reporter assays, and siRNA across cell systems and DRG/SGCs\",\n      \"pmids\": [\"9422773\", \"23871830\", \"25045015\", \"39009095\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Relative contribution of each factor in vivo unresolved\", \"Sp4-Nwk2 surface-trafficking link characterized only in cerebellar granule neurons\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Dissociating mRNA from protein regulation showed GluN1 expression is dominated by post-transcriptional and local-synthesis control rather than transcript abundance.\",\n      \"evidence\": \"Parallel immunofluorescence and in situ hybridization in PC12 cells, estradiol-treated rats, and lesioned hippocampus\",\n      \"pmids\": [\"8226739\", \"8824322\", \"9045729\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular machinery of local translation not identified\", \"Did not pinpoint the post-transcriptional checkpoint\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Defining GluN1 LBD and NTD dynamics answered how the glycine site engages ligand and how the N-terminal domain allosterically tunes gating.\",\n      \"evidence\": \"X-ray crystallography, smFRET, computational free-energy landscapes, mutagenesis, and electrophysiology of recombinant receptors\",\n      \"pmids\": [\"23972471\", \"23454977\", \"26153703\", \"24072709\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Link between isolated-domain dynamics and full-length channel gating inferred\", \"Functional role of long-lived intermediate cleft states unresolved\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Establishing the 1/2/1/2 arrangement and the requirement for LBD-TMD linker freedom answered how GluN1 is positioned in the tetramer and how it transmits force to the pore.\",\n      \"evidence\": \"Disulfide cross-linking with functional recording and structural homology modeling\",\n      \"pmids\": [\"22493736\", \"21746848\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mature vs immature arrangement differences not structurally resolved at the time\", \"Inter-subunit gating coupling detail limited to engineered constraints\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Showing GluN1 globally controls GluN2 gating and characterizing triheteromers clarified the division of labor among subunits in activation and pharmacology.\",\n      \"evidence\": \"SYTANLAAF mutagenesis with kinetic analysis; dominant-negative and FRET/FLIM triheteromer expression strategies with pharmacology\",\n      \"pmids\": [\"25339225\", \"24607230\", \"29483146\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Native abundance of specific triheteromers in vivo not quantified\", \"Structural basis of asymmetric pore contributions resolved later\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Identifying direct binding of σ-1 receptor and D1 dopamine receptors to GluN1 answered how the receptor is allosterically and signal-transductively coupled to other receptor systems.\",\n      \"evidence\": \"AFM imaging, co-IP, proximity ligation, blocking peptide, Ca2+/ERK assays, slice electrophysiology, and behavior\",\n      \"pmids\": [\"24227730\", \"25070539\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stoichiometry and structural interface of these complexes unresolved\", \"Whether σ-1 and D1R compete or co-occupy GluN1 not addressed\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Functional characterization of de novo GRIN1 variants answered how mutations cause disease, distinguishing dominant-negative loss-of-function from gain-of-function mechanisms.\",\n      \"evidence\": \"Two-electrode and whole-cell voltage-clamp of variants in oocytes/HEK cells with trafficking and pharmacological profiling, plus clinical genetics\",\n      \"pmids\": [\"27164704\", \"28228639\", \"29365063\", \"34227748\", \"37734923\", \"36341805\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Genotype-to-phenotype prediction across the variant spectrum incomplete\", \"In vivo neuronal consequences of each variant not modeled\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Discovering native glycine-gated GluN1/GluN3A receptors and their structural basis answered whether GluN1 supports non-canonical signaling in adult brain.\",\n      \"evidence\": \"Native and recombinant electrophysiology with CGP-78608, redox manipulation, proton modulation, selective NAMs, viral knockdown, behavior, and cryo-EM\",\n      \"pmids\": [\"30425244\", \"31601771\", \"27000430\", \"32389749\", \"28365212\", \"38598639\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Endogenous ligands and physiological triggers in vivo only partly defined\", \"Cell-type distribution of GluN3A-containing receptors incompletely mapped\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Identifying NFL, KCTD13, PCDH7, α2δ-1, and glycine-site structure as regulators answered how GluN1 protein stability and surface delivery are controlled.\",\n      \"evidence\": \"Co-IP, ubiquitination assays with site mapping, interaction screen, knockout/knockdown mouse and cell models with electrophysiology and trafficking readouts\",\n      \"pmids\": [\"30143609\", \"37142655\", \"32616769\", \"38615365\", \"31444392\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Integration of these regulators into a single trafficking pathway unresolved\", \"PCDH7 and α2δ-1 mechanisms of NMDAR modulation not fully resolved\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Cryo-EM of full-length human GluN1-GluN2A/C/D and GluN1/GluN3A receptors answered how ligands, allosteric modulators, and blockers act on the assembled receptor.\",\n      \"evidence\": \"Single-particle cryo-EM in multiple ligand and subunit states with mutagenesis validation\",\n      \"pmids\": [\"34186027\", \"36309015\", \"38598639\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Dynamic gating transitions inferred from static states\", \"Triheteromeric receptor structures resolved for limited subunit combinations\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Platelet-lineage Grin1 deletion answered whether GluN1 has a non-neuronal function, revealing a role in megakaryopoiesis and proplatelet formation.\",\n      \"evidence\": \"Cre-loxP lineage-specific knockout, platelet function and Ca2+ assays, cytoskeletal imaging, antibody inhibition, and bleeding-time measurement\",\n      \"pmids\": [\"35245376\", \"28277064\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Subunit composition of megakaryocyte NMDARs not defined\", \"Upstream activating ligand in platelet lineage unclear\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How the many regulators of GluN1 abundance, splicing, and partner assembly are integrated to set receptor composition at specific synapses in vivo remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unified model linking transcriptional, post-transcriptional, and trafficking control\", \"Spatiotemporal logic of isoform and GluN2/GluN3 partner selection unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [11, 39, 16, 43]},\n      {\"term_id\": \"GO:0005216\", \"supporting_discovery_ids\": [11, 39, 43]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [8, 39]},\n      {\"term_id\": \"GO:0005215\", \"supporting_discovery_ids\": [35, 38]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 7, 28, 33]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": []}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [0, 17, 20]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [14, 6]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [27, 29, 30, 43]},\n      {\"term_id\": \"R-HSA-109582\", \"supporting_discovery_ids\": [35, 36]}\n    ],\n    \"complexes\": [\n      \"NMDA receptor (GluN1/GluN2)\",\n      \"GluN1/GluN3A receptor\",\n      \"postsynaptic density\",\n      \"D1R/GluN1 complex\"\n    ],\n    \"partners\": [\n      \"GRIN2A\",\n      \"GRIN3A\",\n      \"SIGMAR1\",\n      \"DRD1\",\n      \"NEFL\",\n      \"KCTD13\",\n      \"PCDH7\",\n      \"CACNA2D1\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":10,"faith_total":10,"faith_pct":100.0}}