DOWN‐REGULATION OF THE SODIUM PUMP FOLLOWING CHRONIC EXPOSURE OF HeLa CELLS AND CHICK EMBRYO HEART CELLS TO OUABAIN

Aiton, James F.; Lamb, J. F.; Ogden, P.

doi:10.1111/j.1476-5381.1981.tb10426.x

Cited by 28 publications

(17 citation statements)

References 17 publications

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“…The inactivated, internalized, pumps are replaced (Boardman et al, 1972) at a rate which is at least 4-fold higher than the turnover rate in the absence of ouabain (Lamb & Ogden, 1982) but slower than the internalization rate (Lamb & Ogden, 1982). As a result, the receptor are downregulated in the presence of cardioactive steroids (Aiton et al, 1981). Ouabain accumulates in the cell due to the high repair rate compared with the ouabain-detoxification rate Aiton et al, 1981;Pollack et al, 1981b).…”

Section: Receptor Recyclingmentioning

confidence: 99%

“…As a result, the receptor are downregulated in the presence of cardioactive steroids (Aiton et al, 1981). Ouabain accumulates in the cell due to the high repair rate compared with the ouabain-detoxification rate Aiton et al, 1981;Pollack et al, 1981b). A recent communication reports that the internalization half-time of ouabain-blocked pumps may be below 30min, indicating that the expression of Na,KATPase molecules at the cell surface may be regulated by short-term and long-term mechanisms (Lamb et al, 1984).…”

Section: Receptor Recyclingmentioning

confidence: 99%

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The receptor function of the Na+, K+-activated adenosine triphosphatase system

Anner¹

1985

Biochemical Journal

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Section: Receptor Recyclingmentioning

confidence: 99%

Section: Receptor Recyclingmentioning

confidence: 99%

The receptor function of the Na+, K+-activated adenosine triphosphatase system

Anner¹

1985

Biochemical Journal

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“…The techniques used in this study have been described in detail elsewhere (Boardman et al 1974;Aiton & Lamb, 1980;Aiton et al 1981) and are summarized below or are explained more fully in the Figure legends. All experiments were carried out at 37°C; the temperature of the experimental plates was maintained on a bench incubator (Townson & Mercer). 8f6Rb influx.…”

Section: Experimental Measurementsmentioning

confidence: 99%

“…Thus growth in sublethal concentrations of ouabain, ethacrynic acid or low-K+ medium all lead to the mis-matching of active cation transport and the passive leak and so induce adaptive increases in the number of sodium pump sites (Boardman, Lamb & McCall, 1972;Aiton, Lamb & Ogden, 1981;Boardman et al 1974). Similarly, growth in Li+ medium can also increase sodium pump site numbers (Boardman, Hume, Lamb & Polson, 1975).…”

Section: Introductionmentioning

confidence: 99%

“…HeLa cells were chosen for two reasons. First, being of human origin (Gey, Coffman & Kubicek, 1952) HeLa cells have retained a high sensitivity to ouabain (Aiton et al 1981); many studies on the effects of serum have been carried out using the relatively ouabain-insensitive murine cell line, 3T3 (eg. see Smith & Rozengurt, 1978), and so accurate estimates of the specific binding of [3H]ouabain have been difficult.…”

Section: Introductionmentioning

confidence: 99%

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EFFECT OF THE SERUM CONCENTRATION OF THE GROWTH MEDIUM ON THE SODIUM PUMP SITE DENSITY OF CULTURED HeLa CELLS

Aiton¹,

Lamb²

1984

Exp Physiol

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SUMMARYThe density of sodium pump sites in the plasma membrane of cultured HeLa cells has been measured as a function of the serum concentration of the cell growth medium. Growth in media containing increased concentrations of serum (from 1 to 20% v/v) leads to an increase in sodium pump site numbers (as measured by the specific binding of [3H]ouabain) and pump activity (as measured by the ouabain-sensitive 8Rb influx). Time-course studies show that (1) new sodium pump sites first appear some 3-6 h after transfer to medium containing an elevated serum concentration and (2) the serum-mediated increase in new sodium pump sites is completely abolished by the protein synthesis inhibitors, cycloheximide and actinomycin D. These results suggest that de novo protein synthesis is required for the development of the serum response. Preliminary characterization of the serum factor responsible for initiating the synthesis of new sodium pump sites indicates that the activity is associated with a high molecular weight serum fraction (> 50000). The different types of interaction seen between the serum effect and other experimental manoeuvres which initiate the synthesis of new pump sites (growth in low-K+ medium, growth in Li+ medium and pre-treatment with exogenous ATP) suggest that there may be more than one pathway for the control of sodium pump site synthesis in cultured HeLa cells.

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Ion transport in a human lens epithelial cell line exposed to hyposmotic and apoptotic stress

Chimote

Adragna

Lauf

2010

Journal Cellular Physiology

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Membrane transport changes in human lens epithelial (HLE-B3) cells under hyposmotic and apoptotic stress were compared. Cell potassium content, K(i), uptake of the K congener rubidium, Rb(i), and water content were measured after hyposmotic stress induced by hypotonicity, and apoptotic stress by the protein-kinase inhibitor staurosporine (STP). Cell water increased in hyposmotic (150 mOsm) as compared to isosmotic (300 mOsm) balanced salt solution (BSS) by >2-fold at 5 min and decreased within 15 min to baseline values accompanied by a 40% K(i) loss commensurate with cell swelling and subsequent cell shrinkage likely due to regulatory volume decrease (RVD). Loss of K(i), and accompanying water, and Rb(i) uptake in hyposmotic BSS were prevented by clotrimazole (CTZ) suggesting water shifts associated with K and Rb flux via intermediate conductance K (IK) channels, also detected at the mRNA and protein level. In contrast, 2 h after 2 microM STP exposure, the cells lost approximately 40% water and approximately 60% K(i), respectively, consistent with apoptotic volume decrease (AVD). Indeed, water and K(i) loss was at least fivefold greater after hyposmotic than after apoptotic stress. High extracellular K and 2 mM 4-aminopyridine (4-AP) but not CTZ significantly reduced apoptosis. Annexin labeling phosphatidylserine (PS) at 15 min suggested loss of lipid asymmetry. Quantitative PCR revealed significant IK channel expression during prolonged hyposmotic stress. Results suggest in HLE-B3 cells, IK channels likely partook in and were down regulated after RVD, whereas pro-apoptotic STP-activation of 4-AP-sensitive voltage-gated K channels preceded or accompanied PS externalization before subsequent apoptosis.

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DOWN‐REGULATION OF THE SODIUM PUMP FOLLOWING CHRONIC EXPOSURE OF HeLa CELLS AND CHICK EMBRYO HEART CELLS TO OUABAIN

Cited by 28 publications

References 17 publications

The receptor function of the Na+, K+-activated adenosine triphosphatase system

The receptor function of the Na+, K+-activated adenosine triphosphatase system

EFFECT OF THE SERUM CONCENTRATION OF THE GROWTH MEDIUM ON THE SODIUM PUMP SITE DENSITY OF CULTURED HeLa CELLS

Ion transport in a human lens epithelial cell line exposed to hyposmotic and apoptotic stress

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