| 1995 |
Co-expression of P2X2 and P2X3 subunits in Xenopus oocytes produced ATP-gated currents that closely resembled those in sensory neurons; these properties could not be accounted for by addition of the two homomeric channels, indicating that P2X2 and P2X3 subunits heteropolymerize to form a new channel with distinct properties. |
Heterologous co-expression in Xenopus oocytes, electrophysiology |
Nature |
High |
7566120
|
| 1997 |
P2X2 and P2X3 subunits were directly shown to co-assemble into heteromeric channels by cross-immunoprecipitation of epitope-tagged subunits expressed via baculovirus in insect cells; co-infected cells showed ATP-evoked currents with agonist sensitivity and desensitization distinct from either homomer. |
Baculovirus expression in Sf9 insect cells, cross-immunoprecipitation with epitope tags, whole-cell patch clamp |
The Journal of Neuroscience |
High |
9254665
|
| 1997 |
Three splice variants of the P2X2 receptor were isolated from rat cerebellum; only the P2X2(b) variant (with a 69-amino acid C-terminal deletion) formed functional homomeric channels in oocytes and showed faster desensitization compared to P2X2(a), indicating that the C-terminal serine/proline-rich region regulates desensitization kinetics. |
cDNA cloning from rat cerebellum, heterologous expression in Xenopus oocytes and mammalian cells, two-electrode voltage clamp, in situ hybridization |
Molecular Pharmacology |
High |
9271346
|
| 1997 |
Extracellular acidification (lowered pH) enhanced the activity of all agonists at the recombinant P2X2 receptor expressed in Xenopus oocytes (~5-fold increase in ATP affinity at pH 6.5, apparent pKa ~7.05), consistent with protonation of the receptor itself rather than the agonist, while only suramin antagonism was significantly affected by pH. |
Two-electrode voltage clamp in Xenopus oocytes expressing recombinant P2X2, systematic pH variation with agonist and antagonist concentration-response curves |
British Journal of Pharmacology |
High |
9257926
|
| 1997 |
The putative extracellular domain (ECD) of P2X2 expressed as a recombinant protein bound [α-32P]ATP specifically and competably by antagonists suramin and cibacron blue, indicating that the extracellular domain contains the ATP-binding site. |
Bacterial expression, metal-affinity purification, UV-crosslinking with [α-32P]ATP, gel filtration / analytical ultracentrifugation |
Biochemical and Biophysical Research Communications |
Medium |
9398614
|
| 1998 |
N-linked glycosylation at three asparagine residues (N182, N239, N298) in the extracellular domain of P2X2 is essential for cell-surface expression; tunicamycin treatment or mutagenesis of all three sites abolished ATP responses and caused intracellular retention of the non-glycosylated receptor. |
Stable HEK-293 transfection, tunicamycin treatment, site-directed mutagenesis, cell-surface biotin labeling, indirect immunofluorescence |
Biochemistry |
High |
9778359
|
| 1998 |
PKA phosphorylation of Ser431 in the intracellular C-terminus of rat P2X2 reduces ATP-activated current amplitude; site-directed S431C mutation abolished the current reduction induced by 8-bromo-cAMP or purified PKA catalytic subunit without affecting inactivation kinetics or reversal potential. |
Whole-cell voltage clamp of stably transfected HEK-293 cells, intracellular perfusion of 8-bromo-cAMP and PKA, site-directed mutagenesis |
Journal of Neurochemistry |
High |
9603227
|
| 1998 |
The P2X2 splice variant P2X2-2 (P2X2b), lacking the Val370-Gln438 C-terminal sequence, desensitizes rapidly and completely compared to the slowly desensitizing wild-type channel when expressed in anterior pituitary GT1 or HEK293 cells, demonstrating that the C-terminal domain controls desensitization rate. |
Expression in GT1 and HEK293 cells, single-cell Ca2+ imaging, whole-cell patch clamp, RT-PCR from enriched pituitary cell fractions |
Molecular Endocrinology |
High |
9658396
|
| 1998 |
Homomeric P2X2 receptors have higher Ca2+ permeability (PCa/PNa ~2.5) compared to P2X3 (~1.2–1.5) or heteromeric P2X2/3 receptors (~1.2–1.5); external Ca2+ blocks P2X2 with half-maximal concentration ~5 mM, while the Ca2+ block of the heteromeric P2X2/3 receptor (~15 mM) matched that of native nodose neurones, supporting that Ca2+ block involves both subunits. |
Whole-cell recording from stably transfected HEK-293 cells and cultured rat nodose neurones, reversal-potential measurements with NMDG and Ca2+ substitution |
The Journal of Physiology |
High |
9625864
|
| 1999 |
Specific amino acids in the C-terminal region of P2X2 regulate desensitization: Val370 immediately after the Lys369 splice site slows desensitization via interaction with an intracellular hydrophobic site; truncation at Lys369 accelerated desensitization >100-fold; neutralization of nearby lysines (especially Lys365) also markedly accelerated desensitization. |
Site-directed mutagenesis, truncation analysis, peptide injection into Xenopus oocytes, two-electrode voltage clamp |
The Journal of Physiology |
High |
10517803
|
| 1999 |
P2X2 receptor expression in the cochlea is concentrated on hair cell stereocilia (endolymphatic surface), inner sulcus cells, and spiral ganglion neurons; voltage-clamped guinea pig hair cells exhibited P2X2-compatible pharmacology, and immunoelectron microscopy localized P2X2 subunits to postsynaptic junctions at both inner and outer hair cells. |
RT-PCR, whole-cell voltage clamp, immunohistochemistry with P2X2-specific antiserum, immunoelectron microscopy |
The Journal of Neuroscience |
High |
10493739
|
| 1999 |
Both Cu2+ and Zn2+ potentiate P2X2 receptor currents in Xenopus oocytes with EC50 ~16–20 µM by increasing apparent ATP affinity (leftward shift of concentration-response curve) in a voltage-independent manner; Cu2+ did not further potentiate in the presence of maximal Zn2+, suggesting a shared binding site or mechanism. This modulation is distinct from P2X4, which is potentiated by Zn2+ but not Cu2+. |
Two-electrode voltage clamp in Xenopus oocytes, concentration-response analysis, voltage-independence testing |
Journal of Neurophysiology |
High |
10322050
|
| 2000 |
Co-expression of P2X2 and P2X6 subunits in Xenopus oocytes formed a heteromeric P2X2/6 receptor with significantly different agonist potencies, biphasic ATP-evoked currents (especially with Zn2+ or low pH), altered pH modulation range, and changed suramin sensitivity compared to the P2X2 homomer, demonstrating that P2X6 modifies P2X2 channel phenotype. |
Two-electrode voltage clamp in Xenopus oocytes, pharmacological characterization with agonists and antagonists, pH and Zn2+ modulation |
The Journal of Neuroscience |
High |
10864944
|
| 2001 |
P2X2 receptor mediates ATP-stimulated parasensory cation absorption in cochlear outer sulcus cells and vestibular transitional cells; ATP but not selective P2Y agonists stimulated transepithelial current (Isc) with a potency order consistent with P2X2 pharmacology, and this response was blocked by suramin or gadolinium. |
Vibrating probe technique for transepithelial current measurement, pharmacological profiling with P2X/P2Y agonists and antagonists |
The Journal of Neuroscience |
Medium |
11717350
|
| 2001 |
Noise exposure (90–120 dB) up-regulated P2X2 receptor mRNA and protein in rat cochlea organ of Corti and spiral ganglion; confocal immunofluorescence showed increased P2X2R labeling on outer hair cell stereocilia and cuticular plates, and whole-cell voltage clamp of OHCs confirmed noise-induced up-regulation of ATP-gated inward currents, indicating adaptive regulation of P2X2 expression by acoustic trauma. |
RT-PCR, western blot, confocal immunofluorescence, whole-cell voltage clamp of isolated outer hair cells |
Neuroreport |
High |
12858039
|
| 2003 |
P2X2 subunits are required for fast excitatory postsynaptic potentials (fEPSPs) mediated by ATP in myenteric S neurons of the mouse small intestine; in P2X2 knockout mice, fEPSPs were insensitive to the P2X antagonist PPADS and ATP failed to depolarize S neurons, while peristaltic contractions were impaired in vitro. |
P2X2 knockout mice, intracellular electrophysiology, pharmacology with PPADS and mecamylamine, RT-PCR, immunohistochemistry, in vitro motility assay |
The Journal of Physiology |
High |
12937291
|
| 2004 |
Homomeric P2X2 receptors (and P2X4, P2X5) are trimers of identical subunits, as are heteromeric P2X1+2 receptors; P2X6 subunits fail to form homotrimers and instead are retained in the ER as tetramers/aggregates, establishing trimeric architecture as the structural hallmark of functional P2X receptors. |
Biochemical analysis (cross-linking, gel electrophoresis, PAGE) in Xenopus oocytes and transfected cells |
Journal of Molecular Biology |
High |
15313628
|
| 2004 |
Co-activation of P2X2 and GABAA receptors containing β subunits (αβ or αβγ) causes cross-inhibition of P2X2 channels, dependent on the C-terminal domain of P2X2 and the intracellular loop of GABAA β subunits; overexpression of minigenes encoding these domains disrupted the cross-inhibition, and the interaction also induced co-clustering of P2X2 and rho1-β3 chimeric receptors at surface clusters in hippocampal neurons. |
Co-expression in Xenopus oocytes, two-electrode voltage clamp, minigene overexpression, co-expression in hippocampal neurons with imaging |
The Journal of Biological Chemistry |
High |
15456793
|
| 2004 |
Pore properties of the P2X2 channel (permeability to large cations, inward rectification, ligand sensitivity) change dynamically depending on channel expression density; Ile328 at the outer mouth of the pore was identified by mutagenesis as critical for these density-dependent changes. |
Two-electrode voltage clamp in Xenopus oocytes with varying cRNA injection levels, site-directed mutagenesis at Ile328 |
The Journal of Physiology |
High |
15107474
|
| 2005 |
The zinc-binding site in rat P2X2 receptors is intersubunit, requiring His120 and His213 from adjacent subunits; mixing H120A and H213A mutant subunits rescued zinc potentiation; trimeric concatamers showed zinc potentiation correlated with the number of intersubunit histidine pairs; H120C/H213C double mutant formed ectopic disulfide bonds between adjacent subunits confirming their proximity. |
Mutagenesis, co-expression of mixed subunits, trimeric concatamers, two-electrode voltage clamp in Xenopus oocytes, disulfide-trapping with immunoblot under non-reducing conditions |
The Journal of Biological Chemistry |
High |
15899882
|
| 2005 |
Heteromeric P2X2/3 receptors require lysine residues from two different subunits for function; single-lysine mutations in P2X2 (K69A or K308A) were rescued by wild-type P2X3 co-expression, but not vice versa, indicating the heteromeric channel contains one P2X2 and two P2X3 subunits. |
Whole-cell recording from HEK cells, co-expression of wild-type and lysine-to-alanine mutant subunits |
Molecular Pharmacology |
High |
16840712
|
| 2005 |
ATP application to dendrites of hippocampal neurons expressing P2X2-GFP caused receptor redistribution and formation of varicose hot spots with higher receptor density; this redistribution was accompanied by activation-dependent enhancement of ATP-evoked current; the T18A substate-specific mutant showed neither redistribution nor activation-dependent current enhancement. |
Live-cell fluorescence imaging of P2X2-GFP in hippocampal neurons, whole-cell voltage clamp, T18A mutant analysis |
Proceedings of the National Academy of Sciences |
High |
11296257
|
| 2005 |
P2X2 and P2X3 knockout mice showed reduced urinary bladder reflexes and decreased pelvic afferent nerve activity in response to bladder distension, and reduced pain behavior in the formalin test; P2X2-/- mice lacked sustained ATP-evoked inward currents in nodose, coeliac, and SCG neurons, while DRG neurons retained only transient currents. |
P2X2 knockout and P2X2/P2X3 double knockout mice, patch-clamp electrophysiology of ganglia neurons, cystometry, pelvic nerve recording, behavioral pain assays |
The Journal of Physiology |
High |
15961431
|
| 2005 |
Fe65 (β-amyloid precursor protein-binding protein) directly interacts with the P2X2 C-terminal domain (but not the naturally occurring P2X2b splice variant lacking part of this domain) as shown by yeast two-hybrid and GST pull-down; Fe65 co-localizes with P2X2 subunits at postsynaptic specializations of excitatory synapses in CA1 hippocampus; co-expression of Fe65 inhibited the time- and activation-dependent increase in ionic selectivity of P2X2 receptors. |
Yeast two-hybrid, GST pull-down, postembedding immunogold electron microscopy, co-immunoprecipitation from brain membrane extracts, co-expression in HEK cells with electrophysiology |
The Journal of Biological Chemistry |
High |
16330549
|
| 2005 |
Visualization by electron microscopy of purified P2X2 protein from baculovirus-Sf9 cells confirmed the trimeric composition of the P2X2 receptor; averaged negative-stain images showed an inverted three-sided pyramid (~215 Å height) with a crown-shaped extracellular domain and three-fold symmetry. |
Baculovirus-Sf9 expression, affinity purification, chemical cross-linking, negative-stain electron microscopy, single-particle averaging |
Biochemical and Biophysical Research Communications |
High |
16219297
|
| 2006 |
Membrane phosphoinositides (PIPs, PIP2) regulate P2X2 channel activity and pore dilation through electrostatic interaction with positively charged residues (Lys365, Lys369) in the proximal C-terminal cytoplasmic domain; PI3K inhibition or K365Q/K369Q mutations accelerated channel desensitization and sped up the decrease in NMDG permeability (pore dilation); GST-tagged C-terminal fusion proteins bound PIPs in vitro and this binding was abolished by K365Q/K369Q mutations. |
Two-electrode voltage clamp in Xenopus oocytes, PI3K inhibition (wortmannin, LY294002), site-directed mutagenesis, GST-fusion protein lipid binding assay, fluorescence membrane association assay in COS-7 cells |
The Journal of Physiology |
High |
16857707
|
| 2007 |
The Thr339Ser mutation in the second transmembrane domain (TM2) of rat P2X2 causes constitutive (spontaneous) channel opening; the additional K308A mutation (but not K69A) abolished this spontaneous activity and also blocked the agonist-like action of suramin and TNP-ATP at T339S receptors, indicating that Lys308 plays a critical role in channel gating distinct from ATP binding. |
Single-channel and whole-cell recording in HEK-293 cells, double and single mutagenesis, pharmacological testing with suramin and TNP-ATP |
The Journal of Neuroscience |
High |
18032665
|
| 2008 |
The neuronal calcium sensor VILIP1 interacts with P2X2 receptors; VILIP1 was identified by proteomic pull-down, confirmed to form a complex in vitro and in vivo with P2X2 receptors, and was shown to regulate P2X2 receptor sensitivity to ATP, peak response, surface expression, and lateral diffusion; the interaction is constitutive but enhanced in an activation- and calcium-dependent manner due to exposure of the VILIP1-binding segment in P2X2; interaction is also enhanced in hippocampal neurons during action potential firing. |
Proteomic pull-down, co-immunoprecipitation from brain tissue, surface expression assays, whole-cell electrophysiology, live-cell imaging of receptor diffusion in hippocampal neurons |
Science Signaling |
High |
18922787
|
| 2009 |
The C-terminus of P2X2 binds directly to PIP2, PIP3, and other phosphoinositides in a lipid-binding assay, while the C-terminus of P2X3 does not; wortmannin inhibition reduced P2X2/3 heteromeric receptor currents in DRG neurons and Xenopus oocytes via both PI3K and PI4K pathways, and PIP2 or PIP3 application partially reversed this inhibition. |
Lipid binding assay with C-terminal GST-fusion proteins, whole-cell patch clamp in DRG neurons, two-electrode voltage clamp in Xenopus oocytes, PI3K/PI4K inhibition |
Molecular Pain |
High |
19671169
|
| 2009 |
Systematic mutagenesis of polar and charged residues in TM2 of rat P2X2 identified Asn333 and Asp349 as located in external and internal vestibules respectively; substitutions at Asn333, Thr336, Ser340 were most likely to cause spontaneously active channels; introduction of positive charges at Thr336, Thr339, Ser340 (by Arg/Lys/His substitution or MTSEA modification of Cys) greatly enhanced outward currents, indicating these residues face the permeation pathway in the open channel. |
Single-channel and whole-cell recording in HEK-293 cells, systematic site-directed mutagenesis of TM2, MTSEA modification of cysteine substitutions |
The Journal of Neuroscience |
High |
19906973
|
| 2011 |
ATP-activated cation current in mouse spermatozoa midpiece is mediated by P2X2; the current was absent in P2rx2-/- mice; the slowly desensitizing, outwardly rectifying current matched biophysical and pharmacological properties of heterologously expressed mouse P2X2; P2rx2-/- males showed normal sperm motility but reduced fertility with frequent mating. |
Whole-cell patch clamp of mouse spermatozoa, P2rx2 knockout mice, pharmacological characterization |
Proceedings of the National Academy of Sciences |
High |
21831833
|
| 2011 |
Colchicine (microtubule disruptor) did not affect ionic currents generated by ATP at P2X2 receptors but inhibited dye (Yo-Pro-1) uptake in Xenopus oocytes and HEK293 cells expressing P2X2, indicating that microtubule integrity is required for the macropore/dye-uptake function of P2X2 but not for its ion channel function. |
Whole-cell electrophysiology and Yo-Pro-1 dye uptake assay in Xenopus oocytes and HEK293 cells, colchicine treatment |
British Journal of Pharmacology |
High |
21306580
|
| 2011 |
P2X2 and P2X5 subunits interact to form heteromeric receptors at the plasma membrane with alternate stoichiometries, as shown by bioluminescence resonance energy transfer (BRET), bimolecular fluorescence complementation, and protein biochemistry; P2X2/5 receptors display pore dilatation, membrane blebbing, and phosphatidylserine exposure—properties previously thought specific to P2X7 receptors. |
BRET, bimolecular fluorescence complementation (BiFC), protein biochemistry, live-cell imaging of membrane blebbing and phosphatidylserine exposure |
The Journal of Neuroscience |
High |
22090499
|
| 2011 |
P2X2 receptor lateral mobility in hippocampal neuron dendrites is mostly Brownian, consists of mobile and slowly-mobile pools, is P2X2-subunit and cell-type specific, and is increased in an activation-dependent manner; VILIP1 calcium-binding protein regulates this lateral mobility. |
Single-molecule quantum dot imaging with simultaneous whole-cell voltage clamp in rat hippocampal neurons |
The Journal of Neuroscience |
High |
22090499
|
| 2011 |
ATP-binding sites of P2X2 receptors are located at intersubunit interfaces; a thiol-reactive ATP analog (NCS-ATP) covalently labeled Asn140 and Leu186 from two adjacent subunits; tethering at these positions had distinct functional consequences—labeling N140 impeded subsequent ATP function while labeling L186 enhanced subsequent ATP function. |
Proximity-dependent tethering with NCS-ATP, single cysteine mutagenesis, whole-cell and single-channel recording in HEK cells, homology modeling |
Proceedings of the National Academy of Sciences |
High |
21576497
|
| 2012 |
Glu167 and Arg290 form a salt bridge in the closed state of rat P2X2 receptor that is disrupted upon ATP binding and channel opening; charge-reversal mutations, mutant-cycle analysis, and disulfide trapping confirmed their close proximity in the closed but not open state; the Arg290/ATP ionic interaction replaces the Glu167/Arg290 salt bridge to promote channel opening. |
Homology modeling, charge-reversal mutagenesis, mutant cycle analysis, disulfide trapping, whole-cell electrophysiology |
Molecular Pharmacology |
High |
23041661
|
| 2012 |
P2X2/3 heteromeric receptors have a 1:2 stoichiometry (one P2X2, two P2X3 subunits) while P2X2/6 receptors have a 2:1 stoichiometry (two P2X2, one P2X6 subunit); determined by co-expression of WT and ATP-binding-site Ala mutants in HEK293 cells and Xenopus oocytes—only selective mutations in the majority subunit abolished agonist responses. |
Site-directed mutagenesis of ATP-binding sites, co-expression of WT and mutant subunits in HEK293 cells and Xenopus oocytes, patch clamp, Ca2+ imaging, protein labeling/PAGE |
The Journal of Biological Chemistry |
High |
22378790
|
| 2013 |
The P2RX2 missense mutation p.V60L abolishes two hallmark P2X2 functions—ATP-evoked inward current and ATP-stimulated macropore permeability (FM1-43 dye uptake); co-expression of mutant and WT P2X2 subunits significantly reduced ATP-activated membrane permeability, indicating dominant-negative effect. P2RX2-null mice developed severe progressive hearing loss, and early noise exposure caused high-frequency hearing loss in young adults. |
Functional expression in heterologous cells, whole-cell electrophysiology, FM1-43 dye uptake assay, P2RX2 knockout mice, audiological testing, linkage analysis in human families |
Proceedings of the National Academy of Sciences |
High |
23345450
|
| 2020 |
ATP activates P2X2 receptors on enteric glial cells to trigger a p38 MAPK-dependent pathway causing cytokine release and a gliosis phenotype; pharmacological blockade and genetic depletion of P2X2 prevented ATP-induced enteric gliosis, inflammation, and dysmotility in postoperative ileus models in mice and humans; ambroxol was identified as a novel P2X2 antagonist. |
P2X2 receptor antagonism and genetic depletion in murine EGCs and human intestinal tissue, p38 MAPK pathway analysis, cytokine quantification, motility assays, pharmacological screening |
EMBO Molecular Medicine |
High |
33332729
|
| 2022 |
P2X2 receptors in medial prefrontal cortex pyramidal neurons regulate vulnerability to chronic stress-induced depressive-like behavior; conditional knockout of P2X2 in pyramidal neurons promoted resilience, while pyramidal neuron-specific P2X2 overexpression increased vulnerability; in vivo fiber-photometry and electrophysiology showed P2X2 regulates mPFC neuronal activity and synapse function. |
Conditional knockout (CamkIIα-Cre), AAV-mediated overexpression, chronic social defeat stress model, in vivo fiber-photometry, patch-clamp electrophysiology, neuronal morphometry |
Theranostics |
High |
35664080
|