Importance of Leu99 in Transmembrane Segment M1 of the Na+,K+-ATPase in the Binding and Occlusion of K+

Einholm, Anja P.; Andersen, Jens Peter; Vilsen, Bente

doi:10.1074/jbc.m702259200

Cited by 37 publications

(41 citation statements)

References 47 publications

(63 reference statements)

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“…This residue is positioned corresponding to L99 of the Na + ,K + -ATPase and L65 of Ca 2+ -ATPase, which are known to function as a gatekeeper that, together with other hydrophobic residues in the vicinity, hold the glutamic acid residue in M4 in correct position for the binding and occlusion of the transported ions (38,39). Hence, there are distinct similarities between the gate control in relation to ion translocation by Na + ,K + -ATPase and Ca 2+ -ATPase and the hydrophobic gate control mechanism of the flippase.…”

Section: Hydrophobic Residues Adjacent To I364 Display Mutational Senmentioning

confidence: 99%

Critical roles of isoleucine-364 and adjacent residues in a hydrophobic gate control of phospholipid transport by the mammalian P4-ATPase ATP8A2

Vestergaard

Coleman²,

Lemmin

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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109

184

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Section: Hydrophobic Residues Adjacent To I364 Display Mutational Senmentioning

confidence: 99%

Critical roles of isoleucine-364 and adjacent residues in a hydrophobic gate control of phospholipid transport by the mammalian P4-ATPase ATP8A2

Vestergaard

Coleman²,

Lemmin

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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109

184

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“…Because the endogenous Na ϩ ,K ϩ -ATPase of the COS-1 cells is ouabain-sensitive, stable cell lines expressing the recombinant ouabain-resistant wild type or mutants could be isolated by ouabain selection (19 -21). To confirm the stable integration of the cDNA carrying the intended single or double mutations, the genomic DNA was isolated, and the integrated cDNA was amplified by PCR using primers that span exon-exon boundaries as described previously (22). In a few cases where the expressed exogenous mutant Na ϩ ,K ϩ -ATPase did not support cell growth in the presence of ouabain, transient co-expression with siRNA to knock down the endogenous COS-1 Na ϩ ,K ϩ -ATPase was carried out as described previously (23,24).…”

Section: Methodsmentioning

confidence: 99%

“…To examine the Na ϩ dependence of phosphorylation, the enzyme was incubated for 15 s in 20 mM Tris (pH 7.5), 3 mM MgCl 2 , 1 mM EGTA, 2 M [␥-32 P]ATP, 20 g/ml oligomycin (to block dephosphorylation), and various concentrations of NaCl as described previously (22,24,26). In this assay, the ionic strength was kept constant at 150 mM by addition of various concentrations of N-methyl-D-glucamine.…”

Section: Methodsmentioning

confidence: 99%

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Importance of a Potential Protein Kinase A Phosphorylation Site of Na+,K+-ATPase and Its Interaction Network for Na+ Binding

Einholm

Nielsen

Holm

et al. 2016

Journal of Biological Chemistry

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The molecular mechanism underlying PKA-mediated regulation of Na ؉ ,K ؉ -ATPase was explored in mutagenesis studies of the potential PKA site at Ser-938 and surrounding charged residues. The phosphomimetic mutations S938D/E interfered with Na ؉ binding from the intracellular side of the membrane, whereas Na ؉ binding from the extracellular side was unaffected. Electrostatic interaction of Glu-998 is of minor importance for the reduction of Na ؉ affinity by phosphomimetic S938E as revealed by combining S938E with E998A.ATPase is a plasma membrane-associated ion pump protein that actively extrudes three Na ϩ ions from the cell while importing two K ϩ ions for each ATP being hydrolyzed (1-4). It is found in all animal cells where its main function is to establish and maintain transmembrane Na ϩ and K ϩ gradients that are fundamental to a variety of physiological processes ranging from electrical excitability of neurons in the brain to Na ϩ reabsorption in the kidney. The Na ϩ ,K ϩ -ATPase belongs to the superfamily of P-type ATPases and is a heterooligomeric protein consisting of a catalytic ␣-subunit, a ␤-subunit required for translocation of the protein complex to the plasma membrane, and a small regulatory protein belonging to the FXYD family (for reviews, see Refs. 4 and 5). The ␣-subunit is made up of a membrane part containing transmembrane helices 1-10 (M1-M10) 2 and a cytoplasmic "head" formed from three subdomains: actuator (A), nucleotide binding (N), and phosphorylation (P) domains (Fig. 1B). During the Na ϩ ,K ϩ -pump cycle (reaction scheme in Fig. 1A), ATP binds to the Nand P-domains, and the ␥-phosphate is transferred to a conserved aspartic acid residue of the P-domain. This phosphorylation is triggered by Na ϩ binding from the cytoplasmic side of the membrane, whereas dephosphorylation with release of inorganic phosphate is triggered by K ϩ binding from the extracellular side. The Na ϩ and K ϩ binding residues are found in the transmembrane helices M4, M5, M6, and M8 (6 -8). Na ϩ ,K ϩ -ATPase alternates between so-called E 1 and E 2 states (1, 2) (see reaction scheme in Fig. 1A). E 1 states bind Na ϩ at three sites denoted I, II, and III, whereas E 2 states prefer K ϩ , binding at two sites, I and II, that overlap considerably with Na ϩ sites I and II. The Na ϩ selectivity of site III is thought to arise in part from interactions of the two C-terminal tyrosines, stabilizing the position of the M5 helix, such that Na ϩ , but not the larger K ϩ ion, can fit into site III, which is the first of the three Na ϩ sites to be occupied when Na ϩ binds from the intracellular side (6,8,9). In addition to the autophosphorylation of the P-domain conserved aspartate, which is central to the reaction cycle of Na ϩ ,K ϩ -ATPase, the Na ϩ ,K ϩ -ATPase activity depends on regulatory phosphorylation by protein kinases (for a review, see Ref. 10). In cardiac myocytes, "kinase-mediated" phosphorylation of the FXYD1 protein stimulates Na ϩ ,K ϩ -ATPase (11). Furthermore, phosphorylation of the Na ϩ ,K ϩ -ATPase ␣-subunit...

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“…Na + /K + ATPases are expressed throughout the adrenal cortex; the highest mRNA expression is in the zona glomerulosa. The Na + /K + and ATP binding sites are located in the α-subunit, whereas the β-subunits are responsible for directing the α-subunit to the plasma membrane (Einholm et al 2007). Na + /K + ATPases transport three Na + ions in exchange for two K + ions, and this process is driven by the hydrolysis of ATP.…”

Section: Atp1a1mentioning

confidence: 99%

Genetics of primary hyperaldosteronism

Dutta

Söderkvist

Gimm

2016

Endocrine-Related Cancer

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Hypertension is a common medical condition and affects approximately 20% of the population in developed countries. Primary aldosteronism is the most common form of secondary hypertension and affects 8-13% of patients with hypertension. The two most common causes of primary aldosteronism are aldosterone-producing adenoma and bilateral adrenal hyperplasia. Familial hyperaldosteronism types I, II and III are the known genetic syndromes, in which both adrenal glands produce excessive amounts of aldosterone. However, only a minority of patients with primary aldosteronism have one of these syndromes. Several novel susceptibility genes have been found to be mutated in aldosterone-producing adenomas: KCNJ5, ATP1A1, ATP2B3, CTNNB1, CACNA1D, CACNA1H and ARMC5. This review describes the genes currently known to be responsible for primary aldosteronism, discusses the origin of aldosterone-producing adenomas and considers the future clinical implications based on these novel insights.

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Importance of Leu99 in Transmembrane Segment M1 of the Na+,K+-ATPase in the Binding and Occlusion of K+

Cited by 37 publications

References 47 publications

Critical roles of isoleucine-364 and adjacent residues in a hydrophobic gate control of phospholipid transport by the mammalian P4-ATPase ATP8A2

Critical roles of isoleucine-364 and adjacent residues in a hydrophobic gate control of phospholipid transport by the mammalian P4-ATPase ATP8A2

Importance of a Potential Protein Kinase A Phosphorylation Site of Na+,K+-ATPase and Its Interaction Network for Na+ Binding

Genetics of primary hyperaldosteronism

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