An Epilepsy-Associated GRIN2A Rare Variant Disrupts CaMKIIα Phosphorylation of GluN2A and NMDA Receptor Trafficking

Vieira, Marta; Nguyen, Thien; Wu, Kunwei; Badger, John D.; Collins, Brett M.; Anggono, Victor; Lü, Wei; Roche, Katherine W.

doi:10.1016/j.celrep.2020.108104

Cited by 41 publications

(54 citation statements)

References 81 publications

(123 reference statements)

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“…These data suggest that SNX27 and pseudo-phosphorylated GluN2A are required but not sufficient on their own to drive the endosomal recycling of NMDARs. This is in contrast with results from a recent study, which found that the GluN2A S1459A phospho-deficient mutant causes a slight but significant reduction in the surface expression of NMDARs 28 . This discrepancy could be due to several reasons, including the age and density of the neurons, experimental protocols and method of analysis.…”

Section: Discussioncontrasting

confidence: 99%

“…Phosphorylation of NMDAR subunits in the C-terminal domain is a common mechanism controlling receptor trafficking and function 25 . A recent study has shown that GluN2A is phosphorylated on its Cterminal domain at Ser-1459 by CaMKIIα both in vitro and in cells 28 , a finding which we confirmed here ( Supplementary Fig. 1).…”

Section: Nmdarssupporting

confidence: 91%

“…SNX27 is known to interact with GluN2 subunits of NMDARs and play a role in receptor trafficking through the intracellular endosomal system [26][27][28]31 . Given that a mechanism underlying SNX27 cargo selection involves the phosphorylation of serine or threonine residues upstream of the PDZ binding motif, we predicted that phosphorylation of GluN2A at Ser-1459 would increase the binding affinity towards SNX27.…”

Section: Camkiiα-dependent Phosphorylation Of Glun2a At Ser-1459 Enhamentioning

confidence: 99%

“…Although the phosphorylation of GluN2A on Ser-1459 is dynamically regulated by neuronal activity in vivo 28 , it is currently unknown whether its phosphorylation by CaMKIIα can also be modulated by cLTP stimulation in primary neurons. To address this, we stimulated primary cortical neurons with glycine for 5 min and immunoprecipitated neuronal lysates with anti-GluN2A-pS1459 antibodies.…”

Section: Camkiiα-dependent Ser-1459 Phosphorylation Is Required For Gmentioning

confidence: 99%

“…The precise subcellular localization, membrane trafficking and synaptic targeting of GluN2-containing NMDARs are largely determined by protein-protein interactions and post-translational modifications in the cytoplasmic C-terminal tails 10,25 . Sorting nexin 27 (SNX27) is a highly conserved regulator of cargo retrieval from endosomes to the plasma membrane that directly interacts with various GluN2 subunits of NMDARs through its N-terminal PDZ (postsynaptic density 95/disc-large/zona occluden-1) domain [26][27][28] . SNX27 forms a complex with retromer (a heterotrimer of VPS26, VPS29 and VSP35) via its direct interaction with VPS26, and acts as a cargo adaptor for retromer-mediated transport from the intracellular endosomes to the cell surface 29,30 .…”

Section: Introductionmentioning

confidence: 99%

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Regulation of NMDA receptor trafficking and gating by activity-dependent CaMKIIα phosphorylation of the GluN2A subunit

Yong

Zhang

Yang

et al. 2021

Preprint

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NMDAR-dependent Ca2+ influx underpins multiple forms of synaptic plasticity. In the adult forebrain, the majority of synaptic NMDAR currents are mediated by GluN2A-containing NMDARs. These receptors are rapidly inserted into synapses during LTP; however, the underlying molecular mechanisms remain poorly understood. Here we show that GluN2A is phosphorylated at Ser-1459 by CaMKIIα in response to glycine stimulation that mimics LTP in primary neurons. Phosphorylation of Ser-1459 promotes GluN2A interaction with the SNX27-retromer complex, therefore enhancing the endosomal recycling of NMDARs. Loss of SNX27 or CaMKIIα function blocks the glycine-induced increase in GluN2A-NMDARs on the neuronal membrane. Interestingly, mutations of Ser-1459, including the rare S1459G human epilepsy variant, prolong decay times of NMDAR-mediated synaptic currents in heterosynapses by increasing the active duration of channel openings. Taken together, these findings not only identify a critical role of Ser-1459 phosphorylation in regulating the function of NMDARs, but also explain how the S1459G epilepsy variant dysregulates NMDAR function.

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Section: Discussioncontrasting

confidence: 99%

Section: Nmdarssupporting

confidence: 91%

Section: Camkiiα-dependent Phosphorylation Of Glun2a At Ser-1459 Enhamentioning

confidence: 99%

Section: Camkiiα-dependent Ser-1459 Phosphorylation Is Required For Gmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Regulation of NMDA receptor trafficking and gating by activity-dependent CaMKIIα phosphorylation of the GluN2A subunit

Yong

Zhang

Yang

et al. 2021

Preprint

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In the fast lane: Receptor trafficking during status epilepticus

Naylor

2023

Epilepsia Open

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Status epilepticus (SE) remains a significant cause of morbidity and mortality and often is refractory to standard first‐line treatments. A rapid loss of synaptic inhibition and development of pharmacoresistance to benzodiazepines (BZDs) occurs early during SE, while NMDA and AMPA receptor antagonists remain effective treatments after BZDs have failed. Multimodal and subunit‐selective receptor trafficking within minutes to an hour of SE involves GABA‐A, NMDA, and AMPA receptors and contributes to shifts in the number and subunit composition of surface receptors with differential impacts on the physiology, pharmacology, and strength of GABAergic and glutamatergic currents at synaptic and extrasynaptic sites. During the first hour of SE, synaptic GABA‐A receptors containing γ2 subunits move to the cell interior while extrasynaptic GABA‐A receptors with δ subunits are preserved. Conversely, NMDA receptors containing N2B subunits are increased at synaptic and extrasynaptic sites, and homomeric GluA1 (“GluA2‐lacking”) calcium permeant AMPA receptor surface expression also is increased. Molecular mechanisms, largely driven by NMDA receptor or calcium permeant AMPA receptor activation early during circuit hyperactivity, regulate subunit‐specific interactions with proteins involved with synaptic scaffolding, adaptin‐AP2/clathrin‐dependent endocytosis, endoplasmic reticulum (ER) retention, and endosomal recycling. Reviewed here is how SE‐induced shifts in receptor subunit composition and surface representation increase the excitatory to inhibitory imbalance that sustains seizures and fuels excitotoxicity contributing to chronic sequela such as “spontaneous recurrent seizures” (SRS). A role for early multimodal therapy is suggested both for treatment of SE and for prevention of long‐term comorbidities.

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Individual NMDA receptor GluN2 subunit signaling domains differentially regulate the postnatal maturation of hippocampal excitatory synaptic transmission and plasticity but not dendritic morphology

Keith,

Wild,

Keith

et al. 2024

Synapse

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N‐methyl‐d‐aspartate receptors (NMDARs) at hippocampal excitatory synapses undergo a late postnatal shift in subunit composition, from an initial prevalence of GluN2B subunit incorporation to a later predominance of GluN2A. This GluN2B to GluN2A shift alters NMDAR calcium conductance dynamics and intracellular molecular signaling that are individually regulated by distinct GluN2 signaling domains and temporally align with developmental alterations in dendritic and synaptic plasticity. However, the impacts of individual GluN2B to GluN2A signaling domains on neuronal development remain unknown. Ionotropic and intracellular signaling domains of GluN2 subunits were separated by creating chimeric GluN2 subunits that were expressed in two transgenic mouse lines. Western blot and immunoprecipitation revealed that roughly one third of native synaptic NMDARs were replaced by transformed NMDARs without altering total synaptic NMDAR content. Schaffer collateral synaptic strength was transiently increased in acutely prepared hippocampal slices at just over 3 weeks of age in animals overexpressing the GluN2B carboxy terminus. Long‐term potentiation (LTP) induction following lower frequency stimulation was regulated by GluN2 ionotropic signaling domains in an age‐dependent manner and LTP maintenance was enhanced by overexpression of the GluN2B CTD in mature animals. After higher frequency stimulation, the induction and maintenance of LTP were increased in young adult animals overexpressing the GluN2B ionotropic signaling domains but reduced in juveniles just over 3 weeks of age. Confocal imaging of green fluorescent protein (GFP)‐ labeled CA1 pyramidal neurons revealed no alterations in dendritic morphology or spine density in mice expressing chimeric GluN2 subunits. These results illustrate how individual GluN2 subunit signaling domains do or do not control physiological and morphological development of hippocampal excitatory neurons and better clarify the neurobiological factors that govern hippocampal maturation.SIGNIFICANCE STATEMENT: A developmental reduction in the magnitude of hippocampal long‐term synaptic potentiation (LTP) and a concomitant improvement in spatial maze performance coincide with greater incorporation of GluN2A subunits into synaptic NMDARs. Corroborating our prior discovery that overexpression of GluN2A‐type ionotropic signaling domains enables context‐based navigation in immature mice, GluN2A‐type ionotropic signaling domain overexpression reduces LTP induction threshold and magnitude in immature mice. Also, we previously found that GluN2B carboxy terminal domain (CTD) overexpression enhances long‐term spatial memory in mature mice and now report that the GluN2B CTD is associated with greater amplitude of LTP after induction in mature mice. Thus, the late postnatal maturation of context encoding likely relies on a shift toward GluN2A‐type ionotropic signaling and a reduction in the threshold to induce LTP while memory consolidation and LTP maintenance are regulated by GluN2B subunit CTD signaling.

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An Epilepsy-Associated GRIN2A Rare Variant Disrupts CaMKIIα Phosphorylation of GluN2A and NMDA Receptor Trafficking

Cited by 41 publications

References 81 publications

Regulation of NMDA receptor trafficking and gating by activity-dependent CaMKIIα phosphorylation of the GluN2A subunit

Regulation of NMDA receptor trafficking and gating by activity-dependent CaMKIIα phosphorylation of the GluN2A subunit

In the fast lane: Receptor trafficking during status epilepticus

Individual NMDA receptor GluN2 subunit signaling domains differentially regulate the postnatal maturation of hippocampal excitatory synaptic transmission and plasticity but not dendritic morphology

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