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.
Biophys J
2016 Dec 06;11111:2430-2439. doi: 10.1016/j.bpj.2016.09.042.
Show Gene links
Show Anatomy links
Intracellular Requirements for Passive Proton Transport through the Na+,K+-ATPase.
Stanley KS
,
Meyer DJ
,
Gatto C
,
Artigas P
.
???displayArticle.abstract???
The Na+,K+-ATPase (NKA or Na/K pump) hydrolyzes one ATP to exchange three intracellular Na+ (Na+i) for two extracellular K+ (K+o) across the plasma membrane by cycling through a set of reversible transitions between phosphorylated and dephosphorylated conformations, alternately opening ion-binding sites externally (E2) or internally (E1). With subsaturating [Na+]o and [K+]o, the phosphorylated E2P conformation passively imports protons generating an inward current (IH), which may be exacerbated in NKA-subunit mutations associated with human disease. To elucidate the mechanisms of IH, we studied the effects of intracellular ligands (transported ions, nucleotides, and beryllium fluoride) on IH and, for comparison, on transient currents measured at normal Na+o (QNa). Utilizing inside-out patches from Xenopus oocytes heterologously expressing NKA, we observed that 1) in the presence of Na+i, IH and QNa were both activated by ATP, but not ADP; 2) the [Na+]i dependence of IH in saturating ATP showed K0.5,Na = 1.8 ± 0.2 mM and the [ATP] dependence at saturating [Na+]i yielded K0.5,ATP = 48 ± 11 μM (in comparison, Na+i-dependent QNa yields K0.5,Na = 0.8 ± 0.2 mM and K0.5,ATP = 0.43 ± 0.03 μM; 3) ATP activated IH in the presence of K+i (∼15% of the IH observed in Na+i) only when Mg2+i was also present; and 4) beryllium fluoride induced maximal IH even in the absence of nucleotide. These data indicate that IH occurs when NKA is in an externally open E2P state with nucleotide bound, a conformation that can be reached through forward Na/K pump phosphorylation of E1, with Na+i and ATP, or by backward binding of K+i to E1, which drives the pump to the occluded E2(2K), where free Pi (at the micromolar levels found in millimolar ATP solutions) promotes external release of occluded K+ by backdoor NKA phosphorylation. Maximal IH through beryllium-fluorinated NKA indicates that this complex mimics ATP-bound E2P states.
Albers,
Biochemical aspects of active transport.
1967, Pubmed
Albers,
Biochemical aspects of active transport.
1967,
Pubmed
Artigas,
Large diameter of palytoxin-induced Na/K pump channels and modulation of palytoxin interaction by Na/K pump ligands.
2004,
Pubmed
Askari,
Reaction of (Na+ + K+)-dependent adenosine triphosphatase with inorganic phosphate. Regulation by Na+, K+, and nucleotides.
1984,
Pubmed
Azizan,
Somatic mutations in ATP1A1 and CACNA1D underlie a common subtype of adrenal hypertension.
2013,
Pubmed
Blanco,
The NA/K-ATPase and its isozymes: what we have learned using the baculovirus expression system.
2005,
Pubmed
Castillo,
Mechanism of potassium ion uptake by the Na(+)/K(+)-ATPase.
2015,
Pubmed
Clausen,
Crystal Structure of the Vanadate-Inhibited Ca(2+)-ATPase.
2016,
Pubmed
Cornelius,
Metal fluoride complexes of Na,K-ATPase: characterization of fluoride-stabilized phosphoenzyme analogues and their interaction with cardiotonic steroids.
2011,
Pubmed
Efthymiadis,
Inward-directed current generated by the Na+,K+ pump in Na(+)- and K(+)-free medium.
1993,
Pubmed
,
Xenbase
Forbush,
Rapid release of 42K and 86Rb from an occluded state of the Na,K-pump in the presence of ATP or ADP.
1987,
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
Friedrich,
ATP1A2 Mutations in Migraine: Seeing through the Facets of an Ion Pump onto the Neurobiology of Disease.
2016,
Pubmed
Friedrich,
The Inner Workings of Proton Slippage through the Sodium Pump.
2018,
Pubmed
Gatto,
Chemical modification with dihydro-4,4'-diisothiocyanostilbene-2,2'-disulfonate reveals the distance between K480 and K501 in the ATP-binding domain of the Na,K-ATPase.
1997,
Pubmed
Gregersen,
Isolation, crystallization and crystal structure determination of bovine kidney Na(+),K(+)-ATPase.
2016,
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
Holmgren,
Three distinct and sequential steps in the release of sodium ions by the Na+/K+-ATPase.
2000,
Pubmed
Huang,
Regulation of (Na++K+)-ATPase by inorganic phosphate: pH dependence and physiological implications.
1984,
Pubmed
Johnson,
A tomato ER-type Ca2+-ATPase, LCA1, has a low thapsigargin-sensitivity and can transport manganese.
2009,
Pubmed
Li,
The third sodium binding site of Na,K-ATPase is functionally linked to acidic pH-activated inward current.
2006,
Pubmed
,
Xenbase
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
Mitchell,
Sodium and proton effects on inward proton transport through Na/K pumps.
2014,
Pubmed
,
Xenbase
Nakao,
Voltage dependence of Na translocation by the Na/K pump.
,
Pubmed
Olesen,
The structural basis of calcium transport by the calcium pump.
2007,
Pubmed
Patti,
Cation Interactions and Membrane Potential Induce Conformational Changes in NaPi-IIb.
2016,
Pubmed
,
Xenbase
Peluffo,
Effect of ADP on Na(+)-Na(+) exchange reaction kinetics of Na,K-ATPase.
2004,
Pubmed
Peluffo,
Electrogenic K+ transport by the Na(+)-K+ pump in rat cardiac ventricular myocytes.
1997,
Pubmed
Post,
Activation by adenosine triphosphate in the phosphorylation kinetics of sodium and potassium ion transport adenosine triphosphatase.
1972,
Pubmed
POST,
AN ENZYMATIC MECHANISM OF ACTIVE SODIUM AND POTASSIUM TRANSPORT.
1965,
Pubmed
POST,
A PHOSPHORYLATED INTERMEDIATE IN ADENOSINE TRIPHOSPHATE-DEPENDENT SODIUM AND POTASSIUM TRANSPORT ACROSS KIDNEY MEMBRANES.
1965,
Pubmed
Poulsen,
Neurological disease mutations compromise a C-terminal ion pathway in the Na(+)/K(+)-ATPase.
2010,
Pubmed
,
Xenbase
Price,
Structure-function relationships in the Na,K-ATPase alpha subunit: site-directed mutagenesis of glutamine-111 to arginine and asparagine-122 to aspartic acid generates a ouabain-resistant enzyme.
1988,
Pubmed
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
Rakowski,
Stoichiometry and voltage dependence of the sodium pump in voltage-clamped, internally dialyzed squid giant axon.
1989,
Pubmed
Ratheal,
Selectivity of externally facing ion-binding sites in the Na/K pump to alkali metals and organic cations.
2010,
Pubmed
,
Xenbase
Rettinger,
Characteristics of Na+/K(+)-ATPase mediated proton current in Na(+)- and K(+)-free extracellular solutions. Indications for kinetic similarities between H+/K(+)-ATPase and Na+/K(+)-ATPase.
1996,
Pubmed
,
Xenbase
SEN,
STOICHIOMETRY AND LOCALIZATION OF ADENOSINE TRIPHOSPHATE-DEPENDENT SODIUM AND POTASSIUM TRANSPORT IN THE ERYTHROCYTE.
1964,
Pubmed
Tavraz,
Diverse functional consequences of mutations in the Na+/K+-ATPase alpha2-subunit causing familial hemiplegic migraine type 2.
2008,
Pubmed
,
Xenbase
Toyoshima,
Trinitrophenyl derivatives bind differently from parent adenine nucleotides to Ca2+-ATPase in the absence of Ca2+.
2011,
Pubmed
Vedovato,
Route, mechanism, and implications of proton import during Na+/K+ exchange by native Na+/K+-ATPase pumps.
2014,
Pubmed
,
Xenbase
Vilsen,
A Glu329-->Gln variant of the alpha-subunit of the rat kidney Na+,K(+)-ATPase can sustain active transport of Na+ and K+ and Na+,K(+)-activated ATP hydrolysis with normal turnover number.
1993,
Pubmed
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
