Quantifying Ca2+ current and permeability in ATP-gated P2X7 receptors

Journal of Biological Chemistry

Volumn 290, Issue 12, 2015, Pages 7930-7942

  Liang, Xin ^a   Samways, Damien S K ^b   Wolf, Kyle ^a   Bowles, Elizabeth A ^a   Richards, Jennifer P ^a   Bruno, Jonathan ^a   Dutertre, Sébastien ^c   DiPaolo, Richard J ^a   Egan, Terrance M ^a  

^a SAINT LOUIS UNIVERSITY SCHOOL OF MEDICINE   (United States)

^b CLARKSON UNIVERSITY   (United States)

^c UNIV MONTPELLIER   (France)

Author keywords

[No Author keywords available]

Indexed keywords

ELECTROPHYSIOLOGY; ENZYME ACTIVITY; MAMMALS;

CROSS-SPECIES; IMMUNE RESPONSE; INFLAMMATORY CELLS; INTRACELLULAR CA; QUANTITATIVE MEASURES; RECEPTOR ACTIVATION; SELECTIVE CHANNELS; SPLICE VARIANTS;

CALCIUM;

ADENOSINE TRIPHOSPHATE; PURINERGIC P2X7 RECEPTOR; CALCIUM CHANNEL;

ANIMAL CELL; ARTICLE; CALCIUM CURRENT; CALCIUM TRANSPORT; CONTROLLED STUDY; GENETIC TRANSFECTION; HORMONE RELEASE; HUMAN; HUMAN CELL; IMMUNE RESPONSE; LYMPHOCYTE; MACROPHAGE; MEMBRANE PERMEABILITY; MONOCYTE; MOUSE; NEUROMODULATION; NONHUMAN; PERITONEAL CAVITY; PRIORITY JOURNAL; SEQUENCE HOMOLOGY; SITE DIRECTED MUTAGENESIS; SYNAPTOSOME; ANIMAL; CELL CULTURE; CYTOLOGY; METABOLISM; PERITONEUM MACROPHAGE; PERMEABILITY; PHYSIOLOGY;

CANIS FAMILIARIS; CAVIA; DANIO RERIO; RATTUS;

ADENOSINE TRIPHOSPHATE; ANIMALS; CALCIUM CHANNELS; CELLS, CULTURED; HUMANS; MACROPHAGES, PERITONEAL; MICE; PERMEABILITY; RECEPTORS, PURINERGIC P2X7;

EID: 84925340801     PISSN: 00219258     EISSN: 1083351X     Source Type: Journal    
DOI: 10.1074/jbc.M114.627810     Document Type: Article

References (100)

1. Egan, T. M., and Khakh, B. S. (2004) Contribution of calcium ions to P2X channel responses. J. Neurosci. 24, 3413-3420
2. North, R. A., and Jarvis, M. F. (2013) P2X receptors as drug targets. Mol. Pharmacol. 83, 759-769
3. Burnstock, G., and Kennedy, C. (2011) P2X receptors in health and disease. Adv. Pharmacol. 61, 333-372
4. Jiang, L.-H. (2012) P2X receptor-mediated ATP purinergic signaling in health and disease. Cell Health Cytoskeleton 4, 83-101
5. Khakh, B. S., and North, R. A. (2012) Neuromodulation by Extracellular ATP and P2X Receptors in the CNS. Neuron 76, 51-69
6. Kaczmarek-Hájek, K., Lörinczi, E., Hausmann, R., and Nicke, A. (2012) Molecular and functional properties of P2X receptors: recent progress and persisting challenges. Purinergic Signal. 8, 375-417
7. Jiang, R., Taly, A., and Grutter, T. (2013) Moving through the gate in ATP-activated P2X receptors. Trends Biochem. Sci. 38, 20-29
8. Yan, Z., Khadra, A., Sherman, A., and Stojilkovic, S. S. (2011) Calcium-dependent block of P2X7 receptor channel function is allosteric. J. Gen. Physiol. 138, 437-452
9. Virginio, C., Church, D., North, R. A., and Surprenant, A. (1997) Effects of divalent cations, protons and calmidazolium at the rat P2X7 receptor. Neuropharmacology 36, 1285-1294
10. Jiang, L. H. (2009) Inhibition of P2X(7) receptors by divalent cations: old action and new insight. Eur. Biophys. J. 38, 339-346
11. Collo, G., Neidhart, S., Kawashima, E., Kosco-Vilbois, M., North, R. A., and Buell, G. (1997) Tissue distribution of the P2X7 receptor. Neuropharmacology 36, 1277-1283
12. Di Virgilio, F., Ceruti, S., Bramanti, P., and Abbracchio, M. P. (2009) Purinergic signalling in inflammation of the central nervous system. Trends Neurosci. 32, 79-87
13. Surprenant, A., and North, R. A. (2009) Signaling at purinergic P2X receptors. Annu. Rev. Physiol. 71, 333-359
14. Grol, M. W., Panupinthu, N., Korcok, J., Sims, S. M., and Dixon, S. J. (2009) Expression, signaling, and function of P2X7 receptors in bone. Purinergic Signal. 5, 205-221
15. Chen, L., and Brosnan, C. F. (2006) Regulation of immune response by P2X7 receptor. Crit. Rev. Immunol. 26, 499-513
16. Gordon, J. L. (1986) Extracellular ATP: effects, sources and fate. Biochem. J. 233, 309-319
17. Zimmermann, H. (2000) Extracellular metabolism of ATP and other nucleotides. Naunyn Schmiedebergs Arch. Pharmacol. 362, 299-309
18. Di Virgilio, F., Boeynaems, J. M., and Robson, S. C. (2009) Extracellular nucleotides as negative modulators of immunity. Curr. Opin. Pharmacol. 9, 507-513
19. Guerra, A. N., Gavala, M. L., Chung, H. S., and Bertics, P. J. (2007) Nucleotide receptor signalling and the generation of reactive oxygen species. Purinergic Signal. 3, 39-51
20. Di Virgilio, F., Pizzo, P., Zanovello, P., Bronte, V., and Collavo, D. (1990) Extracellular ATP as a possible mediator of cell-mediated cytotoxicity. Immunol. Today 11, 274-277
21. Lazarowski, E. R., Boucher, R. C., and Harden, T. K. (2000) Constitutive release of ATP and evidence for major contribution of ecto-nucleotide pyrophosphatase and nucleoside diphosphokinase to extracellular nucleotide concentrations. J. Biol. Chem. 275, 31061-31068
22. Ogura, Y., Sutterwala, F. S., and Flavell, R. A. (2006) The inflammasome: first line of the immune response to cell stress. Cell 126, 659-662
23. Sutterwala, F. S., Ogura, Y., Szczepanik, M., Lara-Tejero, M., Lichtenberger, G. S., Grant, E. P., Bertin, J., Coyle, A. J., Galán, J. E., Askenase, P. W., and Flavell, R. A. (2006) Critical role for NALP3/CIAS1/Cryopyrin in innate and adaptive immunity through its regulation of caspase-1. Immunity 24, 317-327
24. Di Virgilio, F. (2007) Liaisons dangereuses: P2X(7) and the inflammasome. Trends Pharmacol. Sci. 28, 465-472
25. Skaper, S. D., Debetto, P., and Giusti, P. (2009) The P2X7 purinergic receptor: from physiology to neurological disorders. FASEB J. 24, 337-345
26. Lister, M. F., Sharkey, J., Sawatzky, D. A., Hodgkiss, J. P., Davidson, D. J., Rossi, A. G., and Finlayson, K. (2007) The role of the purinergic P2X7 receptor in inflammation. J. Inflamm. 4, 5
27. Scatizzi, J. C., Mavers, M., Hutcheson, J., Young, B., Shi, B., Pope, R. M., Ruderman, E. M., Samways, D. S., Corbett, J. A., Egan, T. M., and Perlman, H. (2009) The CDK domain of p21 is a suppressor of IL-1β-mediated inflammation in activated macrophages. Eur. J. Immunol. 39, 820-825
28. 2+ in the regulation of IL-1β secretion by the P2X7 nucleotide receptor in monocytes, macrophages, and HEK293 fibroblasts. Am. J. Physiol. Cell Physiol. 285, C286-C299
29. MacKenzie, A., Wilson, H. L., Kiss-Toth, E., Dower, S. K., North, R. A., and Surprenant, A. (2001) Rapid secretion of interleukin-1β by microvesicle shedding. Immunity 15, 825-835
30. Qu, Y., Franchi, L., Nunez, G., and Dubyak, G. R. (2007) Nonclassical IL-1β secretion stimulated by P2X7 receptors is dependent on inflammasome activation and correlated with exosome release in murine macrophages. J. Immunol. 179, 1913-1925
31. Hanley, P. J., Kronlage, M., Kirschning, C., del Rey, A., Di Virgilio, F., Leipziger, J., Chessell, I. P., Sargin, S., Filippov, M. A., Lindemann, O., Mohr, S., Königs, V., Schillers, H., Bähler, M., and Schwab, A. (2012) Transient P2X7 receptor activation triggers macrophage death independent of Toll-like receptors 2 and 4, caspase-1, and pannexin-1 proteins. J. Biol. Chem. 287, 10650-10663
32. Glaser, T., Resende, R. R., and Ulrich, H. (2013) Implications of purinergic receptor-mediated intracellular calcium transients in neural differentiation. Cell Commun. Signal. 11, 12
33. Sperlágh, B., Heinrich, A., and Csölle, C. (2007) P2 receptor-mediated modulation of neurotransmitter release-an update. Purinergic Signal. 3, 269-284
34. Weisman, G. A., Camden, J. M., Peterson, T. S., Ajit, D., Woods, L. T., and Erb, L. (2012) P2 receptors for extracellular nucleotides in the central nervous system: role of P2X7 and P2Y(2) receptor interactions in neuroinflammation. Mol. Neurobiol. 46, 96-113
35. Volonte, C., Apolloni, S., Skaper, S. D., and Burnstock, G. (2012) P2X7 receptors: channels, pores and more. CNS Neurol. Discord. Drug Targets 11, 705-721
36. Köles, L., Leichsenring, A., Rubini, P., and Illes, P. (2011) P2 receptor signaling in neurons and glial cells of the central nervous system. Adv. Pharmacol. 61, 441-493
37. Gulbransen, B. D., Bashashati, M., Hirota, S. A., Gui, X., Roberts, J. A., MacDonald, J. A., Muruve, D. A., McKay, D. M., Beck, P. L., Mawe, G. M., Thompson, R. J., and Sharkey, K. A. (2012) Activation of neuronal P2X7 receptor-pannexin-1 mediates death of enteric neurons during colitis. Nat. Med. 18, 600-604
38. Notomi, S., Hisatomi, T., Murakami, Y., Terasaki, H., Sonoda, S., Asato, R., Takeda, A., Ikeda, Y., Enaida, H., Sakamoto, T., and Ishibashi, T. (2013) Dynamic increase in extracellular ATP accelerates photoreceptor cell apoptosis via ligation of P2RX7 in subretinal hemorrhage. PLoS One 8, e53338
39. Faroni, A., Rothwell, S. W., Grolla, A. A., Terenghi, G., Magnaghi, V., and Verkhratsky, A. (2013) Differentiation of adipose-derived stem cells into Schwann cell phenotype induces expression of P2X receptors that control cell death. Cell Death Dis. 4, e743
40. Rubini, P., Pagel, G., Mehri, S., Marquardt, P., Riedel, T., and Illes, P. (2014) Functional P2X7 receptors at cultured hippocampal astrocytes but not neurons. Naunyn Schmiedebergs Arch. Pharmacol. 387, 943-954
41. Deuchars, S. A., Atkinson, L., Brooke, R. E., Musa, H., Milligan, C. J., Batten, T. F., Buckley, N. J., Parson, S. H., and Deuchars, J. (2001) Neuronal P2X7 receptors are targeted to presynaptic terminals in the central and peripheral nervous systems. J. Neurosci. 21, 7143-7152
42. Sperlágh, B., Vizi, E. S., Wirkner, K., and Illes, P. (2006) P2X7 receptors in the nervous system. Prog. Neurobiol. 78, 327-346
43. Alloisio, S., Cervetto, C., Passalacqua, M., Barbieri, R., Maura, G., Nobile, M., and Marcoli, M. (2008) Functional evidence for presynaptic P2X7 receptors in adult rat cerebrocortical nerve terminals. FEBS Lett. 582, 3948-3953
44. Marcoli, M., Cervetto, C., Paluzzi, P., Guarnieri, S., Alloisio, S., Thellung, S., Nobile, M., and Maura, G. (2008) P2X(7) pre-synaptic receptors in adult rat cerebrocortical nerve terminals: a role in ATP-induced glutamate release. J. Neurochem. 105, 2330-2342
45. Sperlágh, B., Köfalvi, A., Deuchars, J., Atkinson, L., Milligan, C. J., Buckley, N. J., and Vizi, E. S. (2002) Involvement of P2X7 receptors in the regulation of neurotransmitter release in the rat hippocampus. J. Neurochem. 81, 1196-1211
46. Cuadra, A. E., Custer, E. E., Bosworth, E. L., and Lemos, J. R. (2014) P2X7 receptors in neurohypophysial terminals: evidence for their role in arginine-vasopressin secretion. J. Cell Physiol. 229, 333-342
47. nd Ed., p. 21, Sinauer Associates, Inc., Sunderland, MA
48. Stojilkovic, S. S., Leiva-Salcedo, E., Rokic, M. B., and Coddou, C. (2014) Regulation of ATP-Gated P2X channels: from redox signaling to interactions with other proteins. Antioxid. Redox. Signal. 21, 953-970
49. Schneggenburger, R., Zhou, Z., Konnerth, A., and Neher, E. (1993) Fractional contribution of calcium to the cation current through glutamate receptor channels. Neuron 11, 133-143
50. Rogers, M., and Dani, J. A. (1995) Comparison of quantitative calcium flux through NMDA, ATP, and ACh receptor channels. Biophys. J. 68, 501-506
51. 2+. Methods Enzymol. 293, 371-383
52. 2+permeability of the sustained proton-induced cation current in adult rat dorsal root ganglion neurons. J. Neurophysiol. 76, 2834-2840
53. Frings, S., Hackos, D. H., Dzeja, C., Ohyama, T., Hagen, V., Kaupp, U. B., and Korenbrot, J. I. (2000) Determination of fractional calcium ion current in cyclic nucleotide-gated channels. Methods Enzymol. 315, 797-817
54. 2+ permeability in recombinant glutamate receptor subtypes. J. Physiol. 538, 25-39
55. 2+-permeable AMPA glutamate receptor channels. J. Gen. Physiol. 112, 623-636
56. Adinolfi, E., Cirillo, M., Woltersdorf, R., Falzoni, S., Chiozzi, P., Pellegatti, P., Callegari, M. G., Sandoná, D., Markwardt, F., Schmalzing, G., and Di Virgilio, F. (2010) Trophic activity of a naturally occurring truncated isoform of the P2X7 receptor. FASEB J. 24, 3393-3404
57. Nicke, A., Kuan, Y. H., Masin, M., Rettinger, J., Marquez-Klaka, B., Bender, O., Górecki, D. C., Murrell-Lagnado, R. D., and Soto, F. (2009) A functional P2X7 splice variant with an alternative transmembrane domain 1 escapes gene inactivation in P2X7 knock-out mice. J. Biol. Chem. 284, 25813-25822
58. Nörenberg, W., Sobottka, H., Hempel, C., Plötz, T., Fischer, W., Schmalzing, G., and Schaefer, M. (2012) Positive allosteric modulation by ivermectin of human but not murine P2X7 receptors. Br. J. Pharmacol. 167, 48-66
59. Davies, J. Q., and Gordon, S. (2005) Isolation and culture of murine macrophages. Methods Mol. Biol. 290, 91-103
60. Lin, W., Haribhai, D., Relland, L. M., Truong, N., Carlson, M. R., Williams, C. B., and Chatila, T. A. (2007) Regulatory T cell development in the absence of functional Foxp3. Nat. Immunol. 8, 359-368
61. 2+ flux in ligand-gated cation channel (P2X4) by actions on lateral portals. J. Biol. Chem. 287, 7594-7602
62. Samways, D. S., Migita, K., Li, Z., and Egan, T. M. (2008) On the role of the first transmembrane domain in cation permeability and flux of the ATP-gated P2X2 receptor. J. Biol. Chem. 283, 5110-5117
63. Edelstein, A., Amodaj, N., Hoover, K., Vale, R., and Stuurman, N. (2010) Computer control of microscopes using microManager. Current Protocols in Molecular Biology 14.20.1-14.20.17, 10.1002/0471142727.mb1420s92
64. Neher, E. (1995) The use of fura-2 for estimating Ca buffers and Ca fluxes. Neuropharmacology 34, 1423-1442
65. Surprenant, A., Rassendren, F., Kawashima, E., North, R. A., and Buell, G. (1996) The cytolytic P2Z receptor for extracellular ATP identified as a P2X receptor (P2X7). Science 272, 735-738
66. Yan, Z., Khadra, A., Li, S., Tomic, M., Sherman, A., and Stojilkovic, S. S. (2010) Experimental characterization and mathematical modeling of P2X7 receptor channel gating. J. Neurosci. 30, 14213-14224
67. Nicke, A. (2004) Learning about structure and function of neuronal nicotinic acetylcholine receptors: lessons from snails. Eur. J. Biochem. 271, 2293
68. Schwarz, N., Drouot, L., Nicke, A., Fliegert, R., Boyer, O., Guse, A. H., Haag, F., Adriouch, S., and Koch-Nolte, F. (2012) Alternative splicing of the N-terminal cytosolic and transmembrane domains of P2X7 controls gating of the ion channel by ADP-ribosylation. PLoS One 7, e41269
69. 2+ buffers. Methods Cell Biol. 99, 1-26
70. Riedel, T., Schmalzing, G., and Markwardt, F. (2007) Influence of extracellular monovalent cations on pore and gating properties of P2X7 receptor-operated single-channel currents. Biophys. J. 93, 846-858
71. Migita, K., Haines, W. R., Voigt, M. M., and Egan, T. M. (2001) Polar residues of the second transmembrane domain influence cation permeability of the ATP-gated P2X(2) receptor. J. Biol. Chem. 276, 30934-30941
72. Samways, D. S., Khakh, B. S., Dutertre, S., and Egan, T. M. (2011) Preferential use of unobstructed lateral portals as the access route to the pore of human ATP-gated ion channels (P2X receptors). Proc. Natl. Acad. Sci. U.S.A. 108, 13800-13805
73. Hattori, M., and Gouaux, E. (2012) Molecular mechanism of ATP binding and ion channel activation in P2X receptors. Nature 485, 207-212
74. Schwede, T., Kopp, J., Guex, N., and Peitsch, M. C. (2003) SWISS-MODEL: an automated protein homology-modeling server. Nucleic Acids Res. 31, 3381-3385
75. Guex, N., and Peitsch, M. C. (1997) SWISS-MODEL and the Swiss-PdbViewer: an environment for comparative protein modeling. Electrophoresis 18, 2714-2723
76. He, M. L., Zemkova, H., Koshimizu, T. A., Tomic, M., and Stojilkovic, S. S. (2003) Intracellular calcium measurements as a method in studies on activity of purinergic P2X receptor channels. Am. J. Physiol. Cell Physiol. 285, 467-479
77. Fischer, W., Wirkner, K., Weber, M., Eberts, C., Köles, L., Reinhardt, R., Franke, H., Allgaier, C., Gillen, C., and Illes, P. (2003) Characterization of P2X3, P2Y1 and P2Y4 receptors in cultured HEK293-hP2X3 cells and their inhibition by ethanol and trichloroethanol. J. Neurochem. 85, 779-790
78. Akerboom, J., Chen, T. W., Wardill, T. J., Tian, L., Marvin, J. S., Mutlu, S., Calderón, N. C., Esposti, F., Borghuis, B. G., Sun, X. R., Gordus, A., Orger, M. B., Portugues, R., Engert, F., Macklin, J. J., Filosa, A., Aggarwal, A., Kerr, R. A., Takagi, R., Kracun, S., Shigetomi, E., Khakh, B. S., Baier, H., Lagnado, L., Wang, S. S., Bargmann, C. I., Kimmel, B. E., Jayaraman, V., Svoboda, K., Kim, D. S., Schreiter, E. R., and Looger, L. L. (2012) Optimization of a GCaMP calcium indicator for neural activity imaging. J. Neurosci. 32, 13819-13840
79. Paukert, M., Hidayat, S., and Gründer, S. (2002) The P2X(7) receptor from Xenopus laevis: formation of a large pore in Xenopus oocytes. FEBS Lett. 513, 253-258
80. Adriouch, S., Dox, C., Welge, V., Seman, M., Koch-Nolte, F., and Haag, F. (2002) Cutting edge: a natural P451L mutation in the cytoplasmic domain impairs the function of the mouse P2X7 receptor. J. Immunol. 169, 4108-4112
81. Taylor, S. R., Gonzalez-Begne, M., Sojka, D. K., Richardson, J. C., Sheardown, S. A., Harrison, S. M., Pusey, C. D., Tam, F. W., and Elliott, J. I. (2009) Lymphocytes from P2X7-deficient mice exhibit enhanced P2X7 responses. J. Leukocyte Biol. 85, 978-986
82. Pankratov, Y., and Lalo, U. (2013) Calcium permeability of ligand-gated Ca channels. Eur. J. Pharmacol. 739, 60-73
83. 2+ permeability and flux in two members of the ATP-gated P2X receptor family. J. Gen. Physiol. 129, 245-256
84. Samways, D. S., Li, Z., and Egan, T. M. (2014) Principles and properties of ion flow in P2X receptors. Front Cell Neurosci. 8, 6
85. Burnashev, N. (1996) Calcium permeability of glutamate-gated channels in the central nervous system. Curr. Opin. Neurobiol. 6, 311-317
86. Burnashev, N. (1998) Calcium permeability of ligand-gated channels. Cell Calcium 24, 325-332
87. Jarvis, M. F., and Khakh, B. S. (2009) ATP-gated P2X cation-channels. Neuropharmacology 56, 208-215
88. Sim, J. A., Park, C. K., Oh, S. B., Evans, R. J., and North, R. A. (2007) P2X1 and P2X4 receptor currents in mouse macrophages. Br. J. Pharmacol. 152, 1283-1290
89. Xu, X. J., Boumechache, M., Robinson, L. E., Marschall, V., Gorecki, D. C., Masin, M., and Murrell-Lagnado, R. D. (2012) Splice variants of the P2X7 receptor reveal differential agonist dependence and functional coupling with pannexin-1. J. Cell Sci. 125, 3776-3789
90. Ozaki, H., Kawai, T., Shuttleworth, C. W., Won, K. J., Suzuki, T., Sato, K., Horiguchi, H., Hori, M., Karaki, H., Torihashi, S., Ward, S. M., and Sanders, K. M. (2004) Isolation and characterization of resident macrophages from the smooth muscle layers of murine small intestine. Neurogastroenterol. Motil. 16, 39-51
91. Gallin, E. K., and McKinney, L. C. (1989) Ion Transport in Phagocytes. in The Neutrophil: Cellular Biochemistry and Physiology (Hallett, M. B., ed) pp. 243-260, CRC Press, Boca Raton, FL
92. Bretschneider, F., Klapperstück, M., Löhn, M., and Markwardt, F. (1995) Nonselective cationic currents elicited by extracellular ATP in human B-lymphocytes. Pflugers Arch. 429, 691-698
93. Baconguis, I., Hattori, M., and Gouaux, E. (2013) Unanticipated parallels in architecture and mechanism between ATP-gated P2X receptors and acid sensing ion channels. Curr. Opin. Struct. Biol. 23, 277-284
94. Browne, L. E., Cao, L., Broomhead, H. E., Bragg, L., Wilkinson, W. J., and North, R. A. (2011) P2X receptor channels show threefold symmetry in ionic charge selectivity and unitary conductance. Nat. Neurosci. 14, 17-18
95. Browne, L. E., Compan, V., Bragg, L., and North, R. A. (2013) P2X7 receptor channels allow direct permeation of nanometer-sized dyes. J. Neurosci. 33, 3557-3566
96. Torres, G. E., Egan, T. M., and Voigt, M. M. (1999) Identification of a domain involved in ATP-gated ionotropic receptor subunit assembly. J. Biol. Chem. 274, 22359-22365
97. Jiang, L. H., Rassendren, F., Spelta, V., Surprenant, A., and North, R. A. (2001) Amino acid residues involved in gating identified in the first membrane-spanning domain of the rat P2X(2) receptor. J. Biol. Chem. 276, 14902-14908
98. Yan, Z., Li, S., Liang, Z., Tomić, M., and Stojilkovic, S. S. (2008) The P2X7 receptor channel pore dilates under physiological ion conditions. J. Gen. Physiol. 132, 563-573
99. Fisher, J. A., Girdler, G., and Khakh, B. S. (2004) Time-resolved measurement of state-specific P2X2 ion channel cytosolic gating motions. J. Neurosci. 24, 10475-10487
100. Toulme, E., Garcia, A., Samways, D., Egan, T. M., Carson, M. J., and Khakh, B. S. (2010) P2X4 receptors in activated C8-B4 cells of cerebellar microglial origin. J. Gen. Physiol. 135, 333-353