| 2019 |
Cryo-EM structures of AMPAR in complex with CNIH3 revealed that CNIH3 lacks an extracellular domain and instead contains four membrane-spanning helices (contrary to previously predicted topology). The protein-protein interaction interface dictating channel modulation and surrounding lipids were identified, providing molecular mechanism for CNIH3-mediated ion channel modulation and AMPAR complex assembly. |
High-resolution cryo-electron microscopy structural determination |
Science |
High |
31806817
|
| 2013 |
CNIH-2 and CNIH-3 selectively promote surface expression of GluA1-containing AMPARs (GluA1A2 heteromers) at hippocampal synapses. Conditional knockout of CNIH-2/-3 caused profound reduction of AMPAR synaptic transmission due to selective loss of GluA1-containing receptors, leaving a residual pool of GluA2A3 heteromers with faster kinetics. TARP γ-8 mediates the selective effect of CNIHs on GluA1 by preventing functional association of CNIHs with non-GluA1 subunits. |
Conditional knockout mice, electrophysiology, genetic epistasis with TARP γ-8 |
Neuron |
High |
23522044
|
| 2012 |
CNIH-2 and CNIH-3 (but not CNIH-1) slow deactivation and desensitization of both GluA2-containing and GluA2-lacking calcium-permeable AMPARs expressed in heterologous cells. They also enhance glutamate sensitivity, single-channel conductance, and calcium permeability of CP-AMPARs while decreasing their block by intracellular polyamines. Overexpression of CNIH-3 in oligodendrocyte precursor cells markedly slowed AMPAR desensitization. |
Electrophysiology in tsA201 cells and rat optic nerve oligodendrocyte precursor cells, CNIH-3 overexpression, anti-CNIH-2/3 surface labeling |
The Journal of Neuroscience |
High |
22815494
|
| 2014 |
CNIH-3 forms a stable complex with tetrameric AMPARs and contributes to transmembrane density. Two clusters of conserved membrane-proximal residues in CNIHs contribute to AMPAR binding. Residues in the extracellular loop of CNIH-2/3 (absent in CNIH-1/4) are critical for both AMPAR interaction and gating modulation. The ligand-binding domain and a linker connecting it to the fourth membrane-spanning segment of AMPAR is the principal contact point with the CNIH-3 extracellular loop. A mutant CNIH-3 was identified that preserves AMPAR binding but has attenuated gating modulation, dissociating binding from gating. |
Single-particle electron microscopy, peptide array screening, in vitro mutagenesis, co-immunoprecipitation, electrophysiology |
The Journal of Neuroscience |
High |
25186755
|
| 2017 |
Lipid-exposed residues in the transmembrane domain (TMD) of GluA2 are critical for CNIH3 function and complex stability. These residues overlap with AMPAR-stargazin contacts in cryo-EM structures. Mutating TMD residues had opposite effects on gating modulation when comparing CNIH3- versus stargazin-bound AMPARs (e.g., GluA2-A793F formed unstable complex with CNIH3 but showed gain-of-function; GluA2-C528L destabilized AMPAR-CNIH3 complex with overall loss of function). Both extracellular and TMD elements contribute independently to CNIH3-mediated gating modulation. |
Site-directed mutagenesis of GluA2 TMD residues, electrophysiology, detergent stability assays, comparison with stargazin modulation |
The Journal of Physiology |
High |
28815591
|
| 2012 |
CNIH-2 serves an evolutionarily conserved role as a cargo exporter from the endoplasmic reticulum (ER), cycling continuously between ER and Golgi in a COPII-dependent manner. When GluA subunits interact with CNIH-2, they recruit it to the cell surface, breaking its ancestral confinement to the early secretory pathway. This mechanism was demonstrated to apply to the related CNIH-2 protein; CNIH-3 is identified as a constituent of native AMPARs by the same proteomic approach. |
Heterologous expression, live cell imaging, COPII-dependent export assay in HEK cells and primary rat neurons, co-immunoprecipitation |
PloS ONE |
Medium |
22292017
|
| 2023 |
CNIH-3 slows AMPAR receptor deactivation from the outset of current decay, consistent with its structural contact at the level of the pore (transmembrane domain). This mechanism is distinct from TARP γ2, which acts via the KGK site of the ligand-binding domain to slow desensitization onset. CNIH-3 modulation of AMPARs is unaffected by alternative splicing of the flip/flop cassette, unlike TARP γ2 modulation. |
Electrophysiology in heterologous cells expressing flip/flop splice variants with various auxiliary subunits |
The Journal of Neuroscience |
Medium |
36931708
|
| 2023 |
CNIH-3 only weakly enhances GluA1 tetramerization and does not enhance GluA2 tetramerization, in contrast to CNIH-2 which enhances tetramerization of both GluA1 and GluA2. CNIH-3's effect on tetramerization is mainly mediated through interactions with the AMPAR transmembrane domain. This defines a functional distinction between CNIH-2 and CNIH-3 in AMPAR biogenesis. |
Blue native PAGE tetramerization assay, surface expression assay, mutant AMPAR analysis in heterologous cells |
The Journal of Biological Chemistry |
Medium |
37673338
|
| 2021 |
CNIH3 loss-of-function in female mice (Cnih3-/-) caused reduced dorsal hippocampal synapse density, enhanced expression of calcium-impermeable AMPAR (GluA2-containing) subunits in synaptosomes, attenuated long-term potentiation maintenance, and weakened short-term spatial memory. These deficits were most pronounced during the metestrus phase of the estrous cycle. Male Cnih3-/- mice were unaffected. Overexpression of Cnih3 in dorsal hippocampus improved short-term spatial memory in female but not male mice. |
Cnih3 knockout mice, viral overexpression, behavioral assays, immunoblotting of synaptosomal fractions, electrophysiology (LTP), super-resolution imaging (SEQUIN) |
Biological Psychiatry |
High |
34548146
|
| 2026 |
Native calcium-permeable AMPARs purified from cerebellum (GluA1/GluA4-containing) associate primarily with CNIH3, with GluA4 occupying B/D positions and GluA1 at A/C positions. Cryo-EM structures in resting, active, and desensitized states characterized the gating mechanism of the native GluA1A4-CNIH3 complex, including a pseudo-4-fold configuration of the ligand-binding domain layer during desensitization. |
Antibody-based native AMPAR purification, cryo-EM structural determination in multiple functional states |
Cell Research |
High |
41840198
|
| 2013 |
CNIH-2 and CNIH-3 show maximum mRNA and protein expression early after birth in rat brain, which then decline towards adulthood, contrasting with GluA1-4 upregulation during postnatal development. Despite reciprocal expression profiles, the ratio of CNIH-2/3 complexed with GluAs remains constant throughout development. Early in development there is an excess of AMPAR-free CNIH-2/3 that may serve the ancestral cargo exporter role, while during development the proportion integrated into AMPAR complexes increases. |
Quantitative PCR, western blotting, co-immunoprecipitation from developing rat brain tissue across postnatal timepoints |
Molecular and Cellular Neurosciences |
Medium |
23403072
|
| 2023 |
Cnih3 knockout in female mice drives broad transcriptomic differences between estrous cycle stages in the dorsal hippocampus, with estrous-responsive genes enriched in oligodendrocyte markers, estrogen response, potassium channels, and synaptic gene splicing. Cnih3 deletion accentuates sex-differential expression at diestrus and estrus, suggesting CNIH3 normally buffers against transcriptional effects of the estrous cycle. |
RNA-sequencing of dorsal hippocampus from Cnih3 knockout and wild-type female mice at each estrous cycle stage, and male mice |
eNeuro |
Medium |
36849260
|
| 2026 |
Cnih3 deletion impairs spatial memory (novel object recognition), operant learning in sucrose self-administration, delays acquisition of fentanyl intravenous self-administration (IVSA) in females, and blunts fentanyl intake during IVSA in both sexes in mice. |
Cnih3 knockout mice, behavioral battery (novel object recognition, sucrose SA, fentanyl IVSA, reversal learning), principal component analysis |
Translational Psychiatry |
Medium |
42056073
|
| 2017 |
A high-throughput screening pipeline identified compounds selective for GluA2-CNIH3 complexes versus GluA2-stargazin complexes. Candidate NAM (VU0612951) and PAM (VU0627849) compounds showed lower IC50/EC50 on stargazin and CNIH3 complexes than on GSG1L or AMPAR alone. VU0539491 showed NAM activity on GluA2(R)-CNIH3 and GluA2(Q) complexes and PAM activity on GluA2(Q)-GSG1L complexes, demonstrating pharmacological distinction of CNIH3-containing AMPAR complexes. |
Cell-based high-throughput screening with voltage-sensitive dye assay and calcium flux assay in HEK cells co-expressing GluA2 and auxiliary subunits |
PloS ONE |
Medium |
28358902
|