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Inward rectification of the IRK1 K+ channel reconstituted in lipid bilayers.
Aleksandrov A, Velimirovic B, Clapham DE.
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Inwardly rectifying potassium (K+) channels (IRK1) were incorporated into lipid bilayers to test the relative contributions of various mechanisms to inward rectification. IRK1 channels were expressed in Xenopus laevis oocytes and oocyte membrane vesicles containing the channels were fused with lipid bilayers. The major properties of the IRK1 channel were similar whether measured in the oocyte membrane or lipid bilayer; the single channel conductance was 21 pS in 140 mM symmetrical [K+] and varied as a square root of external [K+]. Importantly, IRK1 channels display voltage-dependent inward rectification in the absence of divalent ions or charged regulators such as spermine, indicating that they possess an intrinsic rectification mechanism. Although rectification was significantly increased by either Mg2+ or spermine added to the cytoplasmic face of the channel, their effects could not be explained by simple block of the open pore. The Hille and Schwartz (1978) model, originally proposed to explain inward rectification by singly charged blocking particles, cannot be used to explain rectification by multiply charged blocking particles. As an alternative, we propose that in addition to a slow gating mechanism producing long lasting open and closed states, there is a distinct, intrinsic fast gating process amplified by cytoplasmic Mg2+ and/or polyamine binding to the channel.
Ciani,
A model for anomalous rectification: electrochemical-potential-dependent gating of membrane channels.
1978, Pubmed
Ciani,
A model for anomalous rectification: electrochemical-potential-dependent gating of membrane channels.
1978,
Pubmed Fakler,
Strong voltage-dependent inward rectification of inward rectifier K+ channels is caused by intracellular spermine.
1995,
Pubmed
,
Xenbase Fakler,
A structural determinant of differential sensitivity of cloned inward rectifier K+ channels to intracellular spermine.
1994,
Pubmed
,
Xenbase Ficker,
Spermine and spermidine as gating molecules for inward rectifier K+ channels.
1994,
Pubmed
,
Xenbase Hille,
Potassium channels as multi-ion single-file pores.
1978,
Pubmed Ishihara,
The Mg2+ block and intrinsic gating underlying inward rectification of the K+ current in guinea-pig cardiac myocytes.
1989,
Pubmed Kinsey,
Isolation and partial characterization of the plasma membrane of the sea urchin egg.
1980,
Pubmed Kubo,
Primary structure and functional expression of a mouse inward rectifier potassium channel.
1993,
Pubmed
,
Xenbase Kukuljan,
Molecular determinants of ion conduction and inactivation in K+ channels.
1995,
Pubmed Läuger,
Ionic channels with conformational substates.
1985,
Pubmed Leech,
Inward rectification in frog skeletal muscle fibres and its dependence on membrane potential and external potassium.
1981,
Pubmed Logothetis,
The beta gamma subunits of GTP-binding proteins activate the muscarinic K+ channel in heart.
,
Pubmed Lopatin,
Potassium channel block by cytoplasmic polyamines as the mechanism of intrinsic rectification.
1994,
Pubmed
,
Xenbase Loveridge,
Separation of inhibitory activity from biologically active parathyroid hormone in patients with pseudohypoparathyroidism type I.
1986,
Pubmed Lu,
Electrostatic tuning of Mg2+ affinity in an inward-rectifier K+ channel.
1994,
Pubmed
,
Xenbase Matsuda,
Ohmic conductance through the inwardly rectifying K channel and blocking by internal Mg2+.
,
Pubmed Matsuda,
Open-state substructure of inwardly rectifying potassium channels revealed by magnesium block in guinea-pig heart cells.
1988,
Pubmed Pennefather,
Origin of the potassium and voltage dependence of the cardiac inwardly rectifying K-current (IK1).
1992,
Pubmed Silver,
Intrinsic gating of inward rectifier in bovine pulmonary artery endothelial cells in the presence or absence of internal Mg2+.
1990,
Pubmed Taglialatela,
Specification of pore properties by the carboxyl terminus of inwardly rectifying K+ channels.
1994,
Pubmed
,
Xenbase Vandenberg,
Inward rectification of a potassium channel in cardiac ventricular cells depends on internal magnesium ions.
1987,
Pubmed Wible,
Gating of inwardly rectifying K+ channels localized to a single negatively charged residue.
1994,
Pubmed
,
Xenbase Yang,
Control of rectification and permeation by residues in two distinct domains in an inward rectifier K+ channel.
1995,
Pubmed
,
Xenbase
