Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
External Ion Access in the Na/K Pump: Kinetics of Na+, K+, and Quaternary Amine Interaction.
Stanley KS
,
Young VC
,
Gatto C
,
Artigas P
.
???displayArticle.abstract???
Na/K pumps build essential ion gradients across the plasmalemma of animal cells by coupling the extrusion of three Na+, with the import of two K+ and the hydrolysis of one ATP molecule. The mechanisms of selectivity and competition between Na+, K+, and inhibitory amines remain unclear. We measured the effects of external tetrapropylammonium (TPA+) and ethylenediamine (EDA2+) on three different Na/K pump transport modes in voltage-clamped Xenopus oocytes: 1) outward pump current (IP), 2) passive inward H+ current at negative voltages without Na+ or K+ (IH), and 3) transient charge movement reporting the voltage-dependent extracellular binding/release of Na+ (QNa). Both amines competed with K+ to inhibit IP. TPA+ inhibited IH without competing with H+, whereas EDA2+ did not alter IH at pH 7.6. TPA+ competed with Na+ in QNa measurements, reducing Na+-apparent affinity, evidenced by a ∼-75 mV shift in the charge-voltage curve (at 20 mM TPA+) without reduction of the total charge moved (Qtot). In contrast, EDA2+ and K+ did not compete with Na+ to inhibit QNa; both reduced Qtot without decreasing Na+-apparent affinity. EDA2+ (15 mM) right-shifted the charge-voltage curve by ∼+50 mV. Simultaneous occlusion of EDA2+ and Na+ by an E2P conformation unable to reach E1P was demonstrated by voltage-clamp fluorometry. Trypsinolysis experiments showed that EDA2+-bound pumps are much more proteolysis-resistant than Na+-, K+-, or TPA+-bound pumps, therefore uncovering unique EDA2+-bound conformations. K+ effects on QNa and IH were also evaluated in pumps inhibited with beryllium fluoride, a phosphate mimic. K+ reduced Qtot without shifting the charge-voltage curve, indicating noncompetitive effects, and partially inhibited IH to the same extent as TPA+ in non-beryllium-fluorinated pumps. These results demonstrate that K+ interacts with beryllium-fluorinated pumps inducing conformational changes that alter QNa and IH, suggesting that there are two external access pathways for proton transport by IH.
Albers,
Biochemical aspects of active transport.
1967, Pubmed
Albers,
Biochemical aspects of active transport.
1967,
Pubmed
Baker,
The ouabain-sensitive fluxes of sodium and potassium in squid giant axons.
1969,
Pubmed
Bielen,
Dependence of Na+ pump current on external monovalent cations and membrane potential in rabbit cardiac Purkinje cells.
1991,
Pubmed
Bradford,
A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding.
1976,
Pubmed
Cha,
Characterizing voltage-dependent conformational changes in the Shaker K+ channel with fluorescence.
1997,
Pubmed
,
Xenbase
Cornelius,
Metal fluoride complexes of Na,K-ATPase: characterization of fluoride-stabilized phosphoenzyme analogues and their interaction with cardiotonic steroids.
2011,
Pubmed
Costa,
Interactions between Na,K-ATPase alpha-subunit ATP-binding domains.
2003,
Pubmed
Dempski,
The beta subunit of the Na+/K+-ATPase follows the conformational state of the holoenzyme.
2005,
Pubmed
,
Xenbase
Diller,
Electrogenic partial reactions of the gastric H,K-ATPase.
2005,
Pubmed
Dürr,
Control of gastric H,K-ATPase activity by cations, voltage and intracellular pH analyzed by voltage clamp fluorometry in Xenopus oocytes.
2012,
Pubmed
,
Xenbase
Eckstein-Ludwig,
Voltage-dependent inhibition of the Na+,K+ pump by tetraethylammonium.
1998,
Pubmed
,
Xenbase
Forbush,
The interaction of amines with the occluded state of the Na,K-pump.
1988,
Pubmed
Forbush,
Rapid release of 42K or 86Rb from two distinct transport sites on the Na,K-pump in the presence of Pi or vanadate.
1987,
Pubmed
Gadsby,
Steady-state current-voltage relationship of the Na/K pump in guinea pig ventricular myocytes.
1989,
Pubmed
Galva,
Soymilk: an effective and inexpensive blocking agent for immunoblotting.
2012,
Pubmed
Gatto,
Kinetic characterization of tetrapropylammonium inhibition reveals how ATP and Pi alter access to the Na+-K+-ATPase transport site.
2005,
Pubmed
Gatto,
Stabilization of the H,K-ATPase M5M6 membrane hairpin by K+ ions. Mechanistic significance for p2-type atpases.
1999,
Pubmed
Gatto,
Similarities and differences between organic cation inhibition of the Na,K-ATPase and PMCA.
2006,
Pubmed
Geys,
Ligand-dependent effects on the conformational equilibrium of the Na+,K+-ATPase as monitored by voltage clamp fluorometry.
2009,
Pubmed
,
Xenbase
Gregersen,
Isolation, crystallization and crystal structure determination of bovine kidney Na(+),K(+)-ATPase.
2016,
Pubmed
Grădinaru,
Probing the extracellular access channel of the Na,K-ATPase.
2015,
Pubmed
Heyse,
Partial reactions of the Na,K-ATPase: determination of rate constants.
1994,
Pubmed
Hilgemann,
Channel-like function of the Na,K pump probed at microsecond resolution in giant membrane patches.
1994,
Pubmed
Holm,
Arginine substitution of a cysteine in transmembrane helix M8 converts Na+,K+-ATPase to an electroneutral pump similar to H+,K+-ATPase.
2017,
Pubmed
Holmgren,
Three distinct and sequential steps in the release of sodium ions by the Na+/K+-ATPase.
2000,
Pubmed
Holmgren,
Charge translocation by the Na+/K+ pump under Na+/Na+ exchange conditions: intracellular Na+ dependence.
2006,
Pubmed
,
Xenbase
Jorgensen,
Purification and characterization of (Na+, K+)-ATPase. V. Conformational changes in the enzyme Transitions between the Na-form and the K-form studied with tryptic digestion as a tool.
1975,
Pubmed
Jorgensen,
Purification and characterization of (Na+ + K+)-ATPase. VI. Differential tryptic modification of catalytic functions of the purified enzyme in presence of NaCl and KCl.
1977,
Pubmed
Kanai,
Crystal structure of a Na+-bound Na+,K+-ATPase preceding the E1P state.
2013,
Pubmed
Karlish,
A 19-kDa C-terminal tryptic fragment of the alpha chain of Na/K-ATPase is essential for occlusion and transport of cations.
1990,
Pubmed
Kropp,
Kinetics of the inhibition of the Na-K pump by tetrapropylammonium chloride.
1977,
Pubmed
LOWRY,
Protein measurement with the Folin phenol reagent.
1951,
Pubmed
Mares,
Identification of electric-field-dependent steps in the Na(+),K(+)-pump cycle.
2014,
Pubmed
Meier,
Hyperpolarization-activated inward leakage currents caused by deletion or mutation of carboxy-terminal tyrosines of the Na+/K+-ATPase {alpha} subunit.
2010,
Pubmed
,
Xenbase
Meyer,
On the effect of hyperaldosteronism-inducing mutations in Na/K pumps.
2017,
Pubmed
,
Xenbase
Mitchell,
Sodium and proton effects on inward proton transport through Na/K pumps.
2014,
Pubmed
,
Xenbase
Morth,
Crystal structure of the sodium-potassium pump.
2007,
Pubmed
Nakao,
Voltage dependence of Na translocation by the Na/K pump.
,
Pubmed
Nørby,
Kinetics of Na-ATPase activity by the Na,K pump. Interactions of the phosphorylated intermediates with Na+, Tris+, and K+.
1983,
Pubmed
Olesen,
The structural basis of calcium transport by the calcium pump.
2007,
Pubmed
POST,
Membrane adenosine triphosphatase as a participant in the active transport of sodium and potassium in the human erythrocyte.
1960,
Pubmed
POST,
A PHOSPHORYLATED INTERMEDIATE IN ADENOSINE TRIPHOSPHATE-DEPENDENT SODIUM AND POTASSIUM TRANSPORT ACROSS KIDNEY MEMBRANES.
1965,
Pubmed
Peluffo,
Membrane potential-dependent inhibition of the Na+,K+-ATPase by para-nitrobenzyltriethylammonium bromide.
2012,
Pubmed
Peluffo,
Quaternary organic amines inhibit Na,K pump current in a voltage-dependent manner: direct evidence of an extracellular access channel in the Na,K-ATPase.
2004,
Pubmed
Peluffo,
Electrogenic K+ transport by the Na(+)-K+ pump in rat cardiac ventricular myocytes.
1997,
Pubmed
Rakowski,
Stoichiometry and voltage dependence of the sodium pump in voltage-clamped, internally dialyzed squid giant axon.
1989,
Pubmed
Rakowski,
Charge movement by the Na/K pump in Xenopus oocytes.
1993,
Pubmed
,
Xenbase
Rakowski,
A negative slope in the current-voltage relationship of the Na+/K+ pump in Xenopus oocytes produced by reduction of external [K+].
1991,
Pubmed
,
Xenbase
SEN,
STOICHIOMETRY AND LOCALIZATION OF ADENOSINE TRIPHOSPHATE-DEPENDENT SODIUM AND POTASSIUM TRANSPORT IN THE ERYTHROCYTE.
1964,
Pubmed
Sachs,
Effect of tetraethylammonium on the active cation transport system of the red blood cell.
1968,
Pubmed
Schuurmans Stekhoven,
Ethylenediamine as active site probe for Na+/K+-ATPase.
1989,
Pubmed
Shinoda,
Crystal structure of the sodium-potassium pump at 2.4 A resolution.
2009,
Pubmed
Stanley,
Intracellular Requirements for Passive Proton Transport through the Na+,K+-ATPase.
2016,
Pubmed
,
Xenbase
Stanley,
Importance of the Voltage Dependence of Cardiac Na/K ATPase Isozymes.
2015,
Pubmed
,
Xenbase
Toyoshima,
Lumenal gating mechanism revealed in calcium pump crystal structures with phosphate analogues.
2004,
Pubmed
Vedovato,
Route, mechanism, and implications of proton import during Na+/K+ exchange by native Na+/K+-ATPase pumps.
2014,
Pubmed
,
Xenbase
Wang,
A conformation of Na(+)-K+ pump is permeable to proton.
1995,
Pubmed
,
Xenbase
Yaragatupalli,
Altered Na+ transport after an intracellular alpha-subunit deletion reveals strict external sequential release of Na+ from the Na/K pump.
2009,
Pubmed
,
Xenbase
Yoda,
ADP- and K+-sensitive phosphorylated intermediate of Na,K-ATPase.
1986,
Pubmed
