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J Physiol
2009 Nov 15;587Pt 22:5317-24. doi: 10.1113/jphysiol.2009.179309.
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Dynamic aspects of functional regulation of the ATP receptor channel P2X2.
Kubo Y
,
Fujiwara Y
,
Keceli B
,
Nakajo K
.
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The P2X(2) channel is a ligand-gated channel activated by ATP. Functional features that reflect the dynamic flexibility of the channel include time-dependent pore dilatation following ATP application and direct inhibitory interaction with activated nicotinic acetylcholine receptors on the membrane. We have been studying the mechanisms by which P2X(2) channel functionality is dynamically regulated. Using a Xenopus oocyte expression system, we observed that the pore properties, including ion selectivity and rectification, depend on the open channel density on the membrane. Pore dilatation was apparent when the open channel density was high and inward rectification was modest. We also observed that P2X(2) channels show voltage dependence, despite the absence of a canonical voltage sensor. At a semi-steady state after ATP application, P2X(2) channels were activated upon membrane hyperpolarization. This voltage-dependent activation was also [ATP] dependent. With increases in [ATP], the speed of hyperpolarization-induced activation was increased and the conductance-voltage relationship was shifted towards depolarized potentials. Based on analyses of experimental data and various simulations, we propose that these phenomena can be explained by assuming a fast ATP binding step and a rate-limiting voltage-dependent gating step. Complete elucidation of these regulatory mechanisms awaits dynamic imaging of functioning P2X(2) channels.
Barrera,
Atomic force microscopy imaging demonstrates that P2X2 receptors are trimers but that P2X6 receptor subunits do not oligomerize.
2005, Pubmed
Barrera,
Atomic force microscopy imaging demonstrates that P2X2 receptors are trimers but that P2X6 receptor subunits do not oligomerize.
2005,
Pubmed
Ben-Chaim,
The M2 muscarinic G-protein-coupled receptor is voltage-sensitive.
2003,
Pubmed
,
Xenbase
Ben-Chaim,
Movement of 'gating charge' is coupled to ligand binding in a G-protein-coupled receptor.
2006,
Pubmed
,
Xenbase
Brake,
New structural motif for ligand-gated ion channels defined by an ionotropic ATP receptor.
1994,
Pubmed
,
Xenbase
Burnstock,
Physiology and pathophysiology of purinergic neurotransmission.
2007,
Pubmed
Charnet,
Pharmacological and kinetic properties of alpha 4 beta 2 neuronal nicotinic acetylcholine receptors expressed in Xenopus oocytes.
1992,
Pubmed
,
Xenbase
Ding,
Investigating the putative glycine hinge in Shaker potassium channel.
2005,
Pubmed
,
Xenbase
Ding,
Single channel properties of P2X2 purinoceptors.
1999,
Pubmed
,
Xenbase
Edwards,
ATP receptor-mediated synaptic currents in the central nervous system.
1992,
Pubmed
Eickhorst,
Control of P2X(2) channel permeability by the cytosolic domain.
2002,
Pubmed
,
Xenbase
Evans,
ATP mediates fast synaptic transmission in mammalian neurons.
1992,
Pubmed
Figl,
Voltage-jump relaxation kinetics for wild-type and chimeric beta subunits of neuronal nicotinic receptors.
1996,
Pubmed
,
Xenbase
Fisher,
Time-resolved measurement of state-specific P2X2 ion channel cytosolic gating motions.
2004,
Pubmed
Fujiwara,
Regulation of the desensitization and ion selectivity of ATP-gated P2X2 channels by phosphoinositides.
2006,
Pubmed
,
Xenbase
Fujiwara,
Density-dependent changes of the pore properties of the P2X2 receptor channel.
2004,
Pubmed
,
Xenbase
Fujiwara,
Voltage- and [ATP]-dependent gating of the P2X(2) ATP receptor channel.
2009,
Pubmed
,
Xenbase
Jiang,
Crystal structure and mechanism of a calcium-gated potassium channel.
2002,
Pubmed
Kawate,
Crystal structure of the ATP-gated P2X(4) ion channel in the closed state.
2009,
Pubmed
Khakh,
State-dependent cross-inhibition between transmitter-gated cation channels.
2000,
Pubmed
,
Xenbase
Khakh,
Dynamic selectivity filters in ion channels.
1999,
Pubmed
Khakh,
Molecular physiology of P2X receptors and ATP signalling at synapses.
2001,
Pubmed
Koizumi,
Regulation of cell-to-cell communication mediated by astrocytic ATP in the CNS.
2005,
Pubmed
Koshimizu,
Contributions of the C-terminal domain to the control of P2X receptor desensitization.
1999,
Pubmed
Magidovich,
Conserved gating hinge in ligand- and voltage-dependent K+ channels.
2004,
Pubmed
,
Xenbase
Mio,
Reconstruction of the P2X(2) receptor reveals a vase-shaped structure with lateral tunnels above the membrane.
2009,
Pubmed
Mio,
Visualization of the trimeric P2X2 receptor with a crown-capped extracellular domain.
2005,
Pubmed
Nagatomo,
Caffeine activates mouse TRPA1 channels but suppresses human TRPA1 channels.
2008,
Pubmed
,
Xenbase
Nakazawa,
Characterization of voltage-dependent gating of P2X2 receptor/channel.
2005,
Pubmed
,
Xenbase
Nakazawa,
ATP-activated current and its interaction with acetylcholine-activated current in rat sympathetic neurons.
1994,
Pubmed
Nakazawa,
Voltage-dependent gating of ATP-activated channels in PC12 cells.
1997,
Pubmed
North,
Molecular physiology of P2X receptors.
2002,
Pubmed
Ohana,
The metabotropic glutamate G-protein-coupled receptors mGluR3 and mGluR1a are voltage-sensitive.
2006,
Pubmed
,
Xenbase
Roberts,
Molecular properties of P2X receptors.
2006,
Pubmed
Smith,
Identification of amino acids within the P2X2 receptor C-terminus that regulate desensitization.
1999,
Pubmed
,
Xenbase
Surprenant,
Signaling at purinergic P2X receptors.
2009,
Pubmed
Valera,
A new class of ligand-gated ion channel defined by P2x receptor for extracellular ATP.
1994,
Pubmed
,
Xenbase
Virginio,
Pore dilation of neuronal P2X receptor channels.
1999,
Pubmed
Wang,
Structure of the BK potassium channel in a lipid membrane from electron cryomicroscopy.
2009,
Pubmed
Zhou,
Two mechanisms for inward rectification of current flow through the purinoceptor P2X2 class of ATP-gated channels.
1998,
Pubmed
,
Xenbase
