Kinetic mechanism of Na+, K+, Cl−-cotransport as studied by Rb+ influx into HeLa cells: Effects of extracellular monovalent ions

Miyamoto, Hiroshi; Ikehara, Toshitaka; Yamaguchi, Hisao; Hosokawa, Keiko; Yonezu, T; Masuya, Toshio

doi:10.1007/bf01870703

Cited by 42 publications

(31 citation statements)

References 50 publications

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“…However, using a simple competition experiment, we verified that the two cations have similar binding affinities for the cotransporter. These results are supported by studies that showed similar binding constants for K ϩ and Rb ϩ in HeLa cells (35,36), Madin-Darby canine kidney (MDCK) cells (1), and Ehrlich ascites tumor cells (21 (17)] movement likely represents a combination of Na-K-2Cl cotransport (shaded columns in Fig. 5) and other NKCC1-mediated modes of transport.…”

Section: Discussionsupporting

confidence: 62%

Kinetics of hyperosmotically stimulated Na-K-2Cl cotransporter in Xenopus laevis oocytes

Delpire

Gagnon

2011

American Journal of Physiology-Cell Physiology

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A detailed study of hypertonically stimulated Na-K-2Cl cotransport (NKCC1) in Xenopus laevis oocytes was carried out to better understand the 1 K+:1 Cl− stoichiometry of transport that was previously observed. In this study, we derived the velocity equations for K+ influx under both rapid equilibrium assumptions and combined equilibrium and steady-state assumptions and demonstrate that the behavior of the equations and curves in Lineweaver-Burke plots are consistent with a model where Cl− binds first, followed by Na+, a second Cl−, and then K+. We further demonstrate that stimulation of K+ movement by K+ on the trans side is an intrinsic property of a carrier that transports multiple substrates. We also demonstrate that K+ movement through NKCC1 is strictly dependent upon the presence of external Na+, even though only a fraction of Na+ is in fact transported. Finally, we propose that the larger transport of K+, as compared with Na+, is a result of the return of partially unloaded carriers, which masks the net 1Na+:1K+:2Cl− stoichiometry of NKCC1. These data have profound implications for the physiology of Na-K-2Cl cotransport, since transport of K-Cl in some conditions seems to be uncoupled from the transport of Na-Cl.

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Section: Discussionsupporting

confidence: 62%

Kinetics of hyperosmotically stimulated Na-K-2Cl cotransporter in Xenopus laevis oocytes

Delpire

Gagnon

2011

American Journal of Physiology-Cell Physiology

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“…Affinity of the Na + /K + /2Cl -cotransporter for the K + surrogate Rb + increases in HeLa cells when bathing saline Na + concentration increases (Miyamoto et al, 1986). Doublereciprocal plots of Rb + uptake vs Rb + concentration in the bath show that increases in Na + concentration in the bath reduce Kt for K + transport without affecting Jmax (Miyamoto et al, 1986).…”

Section: Na + Competes With K + For Transportmentioning

confidence: 98%

“…The most common finding is that increasing bathing saline Na + concentration produces an increase in K + flux through bumetanide-sensitive Na + /K + /2Cl -cotransporters (for reviews, see Russell, 2000;Haas and Forbush, 2000;Mount et al, 1998). Transport of K + by the Na + /K + /2Cl -cotransporter is stimulated by increases in bathing saline Na + concentration in HeLa cells (Miyamoto et al, 1986), duck erythrocytes (Haas and McManus, 1982) and renal epithelial cell lines (Rindler et al, 1982;Brown and Murer, 1985). Affinity of the Na + /K + /2Cl -cotransporter for the K + surrogate Rb + increases in HeLa cells when bathing saline Na + concentration increases (Miyamoto et al, 1986).…”

Section: Na + Competes With K + For Transportmentioning

confidence: 99%

“…Transport of K + by the Na + /K + /2Cl -cotransporter is stimulated by increases in bathing saline Na + concentration in HeLa cells (Miyamoto et al, 1986), duck erythrocytes (Haas and McManus, 1982) and renal epithelial cell lines (Rindler et al, 1982;Brown and Murer, 1985). Affinity of the Na + /K + /2Cl -cotransporter for the K + surrogate Rb + increases in HeLa cells when bathing saline Na + concentration increases (Miyamoto et al, 1986). Doublereciprocal plots of Rb + uptake vs Rb + concentration in the bath show that increases in Na + concentration in the bath reduce Kt for K + transport without affecting Jmax (Miyamoto et al, 1986).…”

Section: Na + Competes With K + For Transportmentioning

confidence: 99%

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Na+ competes with K+ in bumetanide-sensitive transport by Malpighian tubules ofRhodnius prolixus

Ianowski

Christensen

O’Donnell

2004

Journal of Experimental Biology

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SUMMARY We examined the effects of bathing saline Na+/K+ratio, bumetanide and hydrochlorothiazide on fluid and ion transport by serotonin-stimulated Malpighian tubules of Rhodnius prolixus. Previous pharmacological and electrophysiological studies indicate that a bumetanide-sensitive Na+/K+/2Cl–cotransporter is the primary route for basolateral ion entry into the cell during fluid secretion. The goal of this study was to resolve the apparent conflict between relatively high secretion rates by tubules bathed in K+-free saline and the evidence that Na+/K+/2Cl– cotransporters described in other systems have an absolute requirement for all three ions for translocation. Our measurements of fluid secretion rate, ion fluxes and electrophysiological responses to serotonin show that fluid secretion in K+-free saline is bumetanide sensitive and hydrochlorothiazide insensitive. Dose–response curves of secretion rate versusbumetanide concentration were identical for tubules bathed in K+-free and control saline with IC50 values of 2.6×10–6 mmol l–1 and 2.9×10–6 mmol l–1, respectively. Double-reciprocal plots of K+ flux versus bathing saline K+ concentration showed that increasing Na+concentration in the bathing fluid increased Kt but had no effect on Jmax, consistent with competitive inhibition of K+ transport by Na+. We propose that the competition between Na+ and K+ for transport by the bumetanide-sensitive transporter is part of an autonomous mechanism by which Malpighian tubules regulate haemolymph K+ concentration.

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“…Decrease in the cellular Cl-concentration after treatment with NaNO3 or NaNO2 may be caused by replacement of cellular Cl with the permeant anion, NO3-or NO2-, by accelerated Cl-extrusion as the Na+ concentration increases, or both. A considerable part of Na+ or K+ transport has been linked to Cl-transport in cultured cells (10,11,13); but, lack of change in the cellular K+ concentration suggests that K+ pumping activity (i.e. Na, K-ATPase activity) functions normally during exposure to Na salts.…”

Section: Discussionmentioning

confidence: 99%

Effects of extracellular anions on cell growth of Chinese hamster V-79 cells.

Hirata

Miyakoshi

Oda

et al. 1987

Cell Struct. Funct.

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ABSTRACT. The effects of extracellular anions (10-150 mM, added as Na salts to normal growth medium) on the growth of Chinese hamster V-79 cells were examined. Additions of NaCl and NaNO3 at concentrations greater than 60 mM reduced the growth rate dose-dependently. Several other anions also inhibited cell growth in the decreasing order of potency, SCN->NO2-> NO 3->Br->Cl->gluconate->glutamate->Mes-. When the added anions were removed, the growth rate was restored to the control rate. Cell survival was markedly reduced by the addition of SCN-, but was less affected by other anions (Cl-, NO3-and NO2-) of comparable potency. The respective syntheses of cellular DNA and protein, as estimated from the incorporation of [3H]-thymidine and [14C]leucine, also decreased with the increase in the concentration (60-120 mM) of anions added, the order of potency being SCN-> NO2->NO3-> Cl-. After anion-treatment, the cellular Na+ concentration increased and the cellular Cl-concentration decreased in the order of SCN-> NO2->NO3-, Cl-, but, the cellular K+ concentration did not change significantly. These data suggest that changes in extracellular anions affect cell growth and survival, probably through changes in the intracellular Na+ or Cl-concentration and in the rates of protein and/or DNA synthesis.Proliferation of mammalian cells in culture is known to be affected by changes in extracellular cation concentrations. A reduction in the extracellular Na+ (8) or Ca2+ (7) concentration produces a lack of proliferative response and a decreased intracellular Na+ and/or K+ concentration. Removal of extracellular Na+ (1) or K+ (9) stops the initiation of DNA synthesis stimulated by such mitogens as epidermal growth factor, vasopressin and insulin. Also, intracellular K+ functions in the control of protein synthesis (2). Thus, changes in extracellular cation concentrations appear to affect cell growth through changes in the intracellular cation concentrations and in the synthesis of DNA and/or protein.Various biological responses are reportedly altered when there are changes in the extracellular anions (17); but, the effects of extracellular anions on cell growth have not yet been examined. Therefore, we have examined the effects of anions added as Na salts to normal growth medium on Chinese hamster V-79 cells.

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Kinetic mechanism of Na+, K+, Cl−-cotransport as studied by Rb+ influx into HeLa cells: Effects of extracellular monovalent ions

Cited by 42 publications

References 50 publications

Kinetics of hyperosmotically stimulated Na-K-2Cl cotransporter in Xenopus laevis oocytes

Kinetics of hyperosmotically stimulated Na-K-2Cl cotransporter in Xenopus laevis oocytes

Na+ competes with K+ in bumetanide-sensitive transport by Malpighian tubules ofRhodnius prolixus

Effects of extracellular anions on cell growth of Chinese hamster V-79 cells.

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