P2X purinoceptor 4 is a protein that in humans is encoded by the P2RX4gene.[1][2]
The product of this gene belongs to the family of purinoceptors for ATP. Multiple alternatively spliced transcript variants have been identified for this gene although their full-length natures have not been determined.[2]
The P2X4 subunits can form homomeric or heteromeric receptors.[9] The P2X4 receptor has a typical P2X receptor structure. The zebrafish P2X4 receptor was the first purinergic receptor to be crystallized and have its three-dimensional structure solved, forming the model for the P2X receptor family.[10]
The P2X4 receptor is a ligand-gated cation channel that opens in response to ATP binding.[11] The P2X4 receptor has high calcium permeability, leading to the depolarization of the cell membrane and the activation of various Ca2+-sensitive intracellular processes.[11][12][13] Continued binding leads to increased permeability to N-methyl-D-glucamine (NMDG+) in about 50% of the cells expressing the P2X4 receptor.[11] The desensitization of P2X4 receptors is intermediate when compared to P2X1 and P2X2 receptors.[11]
Pharmacology
Agonists
P2X4 receptors respond to ATP, but not αβmeATP. These receptors are also potentiated by ivermectin, cibacron blue, and zinc.[11]
Antagonists
The main pharmacological distinction between the members of the purinoceptor family is the relative sensitivity to the antagonists suramin and pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS). The product of this gene has the lowest sensitivity for these antagonists[11]
The P2X4 receptor has been linked to neuropathic pain mediated by microgliain vitro and in vivo.[21][22] P2X4 receptors are upregulated following injury.[23] This upregulation allows for increased activation of p38 mitogen-activated protein kinases, thereby increasing the release of brain-derived neurotrophic factor (BDNF) from microglia.[24] BDNF released from microglia induces neuronal hyperexcitability through interaction with the TrkB receptor.[25] More importantly, recent work shows that P2X4 receptor activation is not only necessary for neuropathic pain, but it is also sufficient to cause neuropathic pain.[26]
↑Garcia-Guzman M, Soto F, Gomez-Hernandez JM, Lund PE, Stühmer W (January 1997). "Characterization of recombinant human P2X4 receptor reveals pharmacological differences to the rat homologue". Molecular Pharmacology. 51 (1): 109–18. PMID9016352.
↑Bo X, Kim M, Nori SL, Schoepfer R, Burnstock G, North RA (August 2003). "Tissue distribution of P2X4 receptors studied with an ectodomain antibody". Cell and Tissue Research. 313 (2): 159–65. doi:10.1007/s00441-003-0758-5. PMID12845522.
↑Kawano A, Tsukimoto M, Noguchi T, Hotta N, Harada H, Takenouchi T, Kitani H, Kojima S (March 2012). "Involvement of P2X4 receptor in P2X7 receptor-dependent cell death of mouse macrophages". Biochemical and Biophysical Research Communications. 419 (2): 374–80. doi:10.1016/j.bbrc.2012.01.156. PMID22349510.
↑Solini A, Santini E, Chimenti D, Chiozzi P, Pratesi F, Cuccato S, Falzoni S, Lupi R, Ferrannini E, Pugliese G, Di Virgilio F (May 2007). "Multiple P2X receptors are involved in the modulation of apoptosis in human mesangial cells: evidence for a role of P2X4". American Journal of Physiology. Renal Physiology. 292 (5): F1537–47. doi:10.1152/ajprenal.00440.2006. PMID17264311.
↑Shen JB, Pappano AJ, Liang BT (February 2006). "Extracellular ATP-stimulated current in wild-type and P2X4 receptor transgenic mouse ventricular myocytes: implications for a cardiac physiologic role of P2X4 receptors". FASEB Journal. 20 (2): 277–84. doi:10.1096/fj.05-4749com. PMID16449800.
↑de Rivero Vaccari JP, Bastien D, Yurcisin G, Pineau I, Dietrich WD, De Koninck Y, Keane RW, Lacroix S (February 2012). "P2X4 receptors influence inflammasome activation after spinal cord injury". The Journal of Neuroscience. 32 (9): 3058–66. doi:10.1523/JNEUROSCI.4930-11.2012. PMID22378878.
↑Shigetomi E, Kato F (March 2004). "Action potential-independent release of glutamate by Ca2+ entry through presynaptic P2X receptors elicits postsynaptic firing in the brainstem autonomic network". The Journal of Neuroscience. 24 (12): 3125–35. doi:10.1523/JNEUROSCI.0090-04.2004. PMID15044552.
↑Koshimizu TA, Van Goor F, Tomić M, Wong AO, Tanoue A, Tsujimoto G, Stojilkovic SS (November 2000). "Characterization of calcium signaling by purinergic receptor-channels expressed in excitable cells". Molecular Pharmacology. 58 (5): 936–45. PMID11040040.
↑Qureshi OS, Paramasivam A, Yu JC, Murrell-Lagnado RD (November 2007). "Regulation of P2X4 receptors by lysosomal targeting, glycan protection and exocytosis". Journal of Cell Science. 120 (Pt 21): 3838–49. doi:10.1242/jcs.010348. PMID17940064.
↑Royle SJ, Bobanović LK, Murrell-Lagnado RD (September 2002). "Identification of a non-canonical tyrosine-based endocytic motif in an ionotropic receptor". The Journal of Biological Chemistry. 277 (38): 35378–85. doi:10.1074/jbc.M204844200. PMID12105201.
Maruyama K, Sugano S (January 1994). "Oligo-capping: a simple method to replace the cap structure of eukaryotic mRNAs with oligoribonucleotides". Gene. 138 (1–2): 171–4. doi:10.1016/0378-1119(94)90802-8. PMID8125298.
Garcia-Guzman M, Stühmer W, Soto F (July 1997). "Molecular characterization and pharmacological properties of the human P2X3 purinoceptor". Brain Research. Molecular Brain Research. 47 (1–2): 59–66. doi:10.1016/S0169-328X(97)00036-3. PMID9221902.
Suzuki Y, Yoshitomo-Nakagawa K, Maruyama K, Suyama A, Sugano S (October 1997). "Construction and characterization of a full length-enriched and a 5'-end-enriched cDNA library". Gene. 200 (1–2): 149–56. doi:10.1016/S0378-1119(97)00411-3. PMID9373149.
Korenaga R, Yamamoto K, Ohura N, Sokabe T, Kamiya A, Ando J (May 2001). "Sp1-mediated downregulation of P2X4 receptor gene transcription in endothelial cells exposed to shear stress". American Journal of Physiology. Heart and Circulatory Physiology. 280 (5): H2214–21. PMID11299224.
Glass R, Loesch A, Bodin P, Burnstock G (May 2002). "P2X4 and P2X6 receptors associate with VE-cadherin in human endothelial cells". Cellular and Molecular Life Sciences. 59 (5): 870–81. doi:10.1007/s00018-002-8474-y. PMID12088286.
Yamamoto K, Sokabe T, Ohura N, Nakatsuka H, Kamiya A, Ando J (August 2003). "Endogenously released ATP mediates shear stress-induced Ca2+ influx into pulmonary artery endothelial cells". American Journal of Physiology. Heart and Circulatory Physiology. 285 (2): H793–803. doi:10.1152/ajpheart.01155.2002. PMID12714321.
Yeung D, Kharidia R, Brown SC, Górecki DC (March 2004). "Enhanced expression of the P2X4 receptor in Duchenne muscular dystrophy correlates with macrophage invasion". Neurobiology of Disease. 15 (2): 212–20. doi:10.1016/j.nbd.2003.10.014. PMID15006691.
Yang A, Sonin D, Jones L, Barry WH, Liang BT (September 2004). "A beneficial role of cardiac P2X4 receptors in heart failure: rescue of the calsequestrin overexpression model of cardiomyopathy". American Journal of Physiology. Heart and Circulatory Physiology. 287 (3): H1096–103. doi:10.1152/ajpheart.00079.2004. PMID15130891.
Brown DA, Bruce JI, Straub SV, Yule DI (September 2004). "cAMP potentiates ATP-evoked calcium signaling in human parotid acinar cells". The Journal of Biological Chemistry. 279 (38): 39485–94. doi:10.1074/jbc.M406201200. PMID15262999.
Fountain SJ, North RA (June 2006). "A C-terminal lysine that controls human P2X4 receptor desensitization". The Journal of Biological Chemistry. 281 (22): 15044–9. doi:10.1074/jbc.M600442200. PMID16533808.
Jelínková I, Yan Z, Liang Z, Moonat S, Teisinger J, Stojilkovic SS, Zemková H (October 2006). "Identification of P2X4 receptor-specific residues contributing to the ivermectin effects on channel deactivation". Biochemical and Biophysical Research Communications. 349 (2): 619–25. doi:10.1016/j.bbrc.2006.08.084. PMID16949036.
Solini A, Santini E, Chimenti D, Chiozzi P, Pratesi F, Cuccato S, Falzoni S, Lupi R, Ferrannini E, Pugliese G, Di Virgilio F (May 2007). "Multiple P2X receptors are involved in the modulation of apoptosis in human mesangial cells: evidence for a role of P2X4". American Journal of Physiology. Renal Physiology. 292 (5): F1537–47. doi:10.1152/ajprenal.00440.2006. PMID17264311.