Membrane Fluidity and Phospholipid Composition in Relation to Sulfur Amino Acid Intake in Brush Border Membranes of Rat Kidney

Chesney, Russell W.; Gusowski, Naomi; Zelikovic, Israel

doi:10.1203/00006450-198612000-00024

Cited by 9 publications

(9 citation statements)

References 29 publications

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“…This commentary will focus upon methods by which one can better understand the regulation of the gene that encodes the TauT. We have approached the problem of the signal for the adaptive response using a variety of different tools (Chesney 1985, Chesney et al. 1985, 1986a, b, Jones et al.…”

Section: Methodsmentioning

confidence: 99%

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The taurine transporter: mechanisms of regulation

Han¹,

Patters²,

Jones³

et al. 2006

Acta Physiologica

134

142

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Taurine transport undergoes an adaptive response to changes in taurine availability. Unlike most amino acids, taurine is not metabolized or incorporated into protein but remains free in the intracellular water. Most amino acids are reabsorbed at rates of 98-99%, but reabsorption of taurine may range from 40% to 99.5%. Factors that influence taurine accumulation include ionic environment, electrochemical charge, and post-translational and transcriptional factors. Among these are protein kinase C (PKC) activation and transactivation or repression by proto-oncogenes such as WT1, c-Jun, c-Myb and p53. Renal adaptive regulation of the taurine transporter (TauT) was studied in vivo and in vitro. Site-directed mutagenesis and the oocyte expression system were used to study post-translational regulation of the TauT by PKC. Reporter genes and Northern and Western blots were used to study transcriptional regulation of the taurine transporter gene (TauT). We demonstrated that (i) the body pool of taurine is controlled through renal adaptive regulation of TauT in response to taurine availability; (ii) ionic environment, electrochemical charge, pH, and developmental ontogeny influence renal taurine accumulation; (iii) the fourth segment of TauT is involved in the gating of taurine across the cell membrane, which is controlled by PKC phosphorylation of serine 322 at the post-translational level; (iv) expression of TauT is repressed by the p53 tumour suppressor gene and is transactivated by proto-oncogenes such as WT1, c-Jun, and c-Myb; and (v) over-expression of TauT protects renal cells from cisplatin-induced nephrotoxicity.

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Section: Methodsmentioning

confidence: 99%

“…At times the spin resonance of membranes can be a measure of membrane fluidity and of the capacity for proteins to be inserted into plasma membranes. No differences were evident in rat BBMV using two distinct membrane‐probing dyes (Chesney et al. 1986a).…”

Section: Taurine and Taurine Transport Propertiesmentioning

confidence: 99%

The taurine transporter: mechanisms of regulation

Han¹,

Patters²,

Jones³

et al. 2006

Acta Physiologica

134

142

View full text Add to dashboard Cite

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“…The basolateral membrane has been suggested to have greater "fluidity" than the brush border membrane (Le Grimellec et al, 1983;Hise et al, 1984;Verkman and Ives, 1986;Molitoris and Hoilien, 1987); lifetime heterogeneity studies of parinaric acids showed a different structure of gel and fluid lipid domains (Illsley et al, 1988). Membrane fluidity of apical vesicles has been shown to be modulated by dietary phosphate, lipid content, animal age, and other Address correspondence to Dr. A. S. Verkman. factors (Chesney et al, 1986;Brasitus et al, 1984Brasitus et al, , 1986Medow and Segal., 1987).…”

Section: Introductionmentioning

confidence: 99%

Cell membrane fluidity in the intact kidney proximal tubule measured by orientation-independent fluorescence anisotropy imaging

Fushimi

Dix

Verkman

1990

Biophysical Journal

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Membrane fluidity was measured in the isolated perfused proximal tubule from rabbit kidney. The apical and basolateral plasma membranes of tubule cells were stained separately with the fluidity-sensitive fluorophore trimethylammonium-diphenyl-hexatriene (TMA-DPH) by luminal or bath perfusion. Fluorescence anisotropy (r) of TMA-DPH was mapped with spatial resolution using an epifluorescence microscope (excitation 380 nm, emission greater than 410 nm) equipped with rotatable polarizers and a quantitative imaging system. To measure r without the confounding effects of fluorophore orientation, images were recorded with emission polarizer parallel and perpendicular to a continuum of orientations of the excitation polarizer. The theoretical basis of this approach was developed and its limitations were evaluated by mathematical modeling. The tubule inner surface (brush border) was brightly stained when the lumen was perfused with 1 microM TMA-DPH for 5 min; apical membrane r was 0.281 +/- 0.006 (23 degrees C). Staining of the tubule basolateral membrane by addition of TMA-DPH to the bath gave a significantly lower r of 0.242 +/- 0.010 (P less than 0.005); there was no staining of the brush border membrane. To interpret anisotropy images quantitatively, effects of tubule geometry, TMA-DPH lifetime, fluorescence anisotropy decay, and objective-depolarization were evaluated. Steady-state and time-resolved r and lifetimes in the intact tubule, measured by a nanosecond pulsed microscopy method, were compared with results in isolated apical and basolateral membrane vesicles from rabbit proximal tubule measured by cuvette fluorometry; r was 0.281 (apical membrane) and 0.276 (basolateral membrane) (23 degrees C). These results establish a methodology to quantitate membrane fluidity in the intact proximal tubule, and demonstrate a significantly higher fluidity in the basolateral membrane than in the apical membrane.

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“…It has been shown that the change in the initial rate of Na'-taurine uptake and V,,, in the taurine-deficient animal are not related to changes in the phospholipid composition and fatty acid content of the luminal membrane (26). On the other hand, we were able to demonstrate a 40% decrease in the phosphatidylcholine and phosphatidylethanolamine content of brush border membranes prepared from animals fed the P-T+ diet, associated with a 15% reduction in oleic, stearic, and linoleic acid, and a 15% increase in palmitic acid in the phosphatidylcholine and phosphatidylethanolamine fractions (27).…”

Section: Discussionmentioning

confidence: 99%

Adaptation to Taurine Deprivation in the Phosphate-Depleted Rat

1991

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ABSTRACT. The nonessential amino acid taurine, which is inert in renal tissue, was used to study renal adaptation in the presence of phosphate (P) depletion in the rat. Weanling rats were placed on the control diet (0.7% P, normal taurine) for 4 wk, then fed one of the experimental diets or continued on the control diet for 1 wk. The diets used were 1 ) P'T-(0.7% P, low taurine), 2) P-T+ (0.1% P, normal taurine); and 3) P-T-(0.1% P, low taurine). Taurine deficiency was associated with avid tubular reabsorption of taurine, irrespective of P status. This was associated with a 4-to 5-fold increase in the V,,, of uptake ( p < 0.001). On the other hand, P depletion increased the Km of taurine uptake by 6.6-to 9.5-fold, suggesting a decrease in the affinity of the taurine symport ( p < 0.001).This was independent of the taurine status of the animals. Although there was no effect of diet on the urinary excretion of 8-alanine, P depletion, irrespective of taurine status, resulted in a 2-fold increase in the Km of 8-alanine uptake. We conclude that the taurinuria of P depletion is reversed in taurine deprivation. The adaptive response involves an increase in the V,,, of uptake. However, the increase in Km of taurine uptake observed in P depletion does not reverse with taurine depletion. (Pediatr Res 30: 146-149, 1991) Abbreviations P, phosphorus BBMV, brush border membrane vesicle HEPES, N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid P+T-, phosphate replete, taurine-depleted P-T-, phosphate-and taurine-depleted P-T+, phosphate-depleted, taurine replete The renal tubular epithelium is able to conserve amino acids during periods of decreased dietary intake. Rats or mice fed diets low in sulfur-containing amino acids adapt by increasing the tubular reabsorption of these amino acids, particularly taurine (1, 2). The adaptive response manifests at the luminal surface by enhanced taurine uptake by BBMV prepared from rats fed these diets (3). These changes are associated with an increase in the initial rate of uptake (V,,,) rather than a decrease in the affinity of the symport (Km) (3). The physiologic signal(s) for the observed changes relate, in part, to alterations in the renal cortical content of taurine (4, 5). On the other hand, it has been shown that vitamin D-and/or phosphate-depleted rats develop taurinuria in the absence of secondary hyperparathyroidism (6). The taurinuria manifests at the renal brush border membrane by a decrease in the affinity of the taurine symport, resulting in decreased accumulation of taurine by BBMV (7). No changes could be elicited for the V,,, of uptake. In addition, the perturbation in uptake was not associated with alterations in plasma or renal cortex taurine concentrations, suggesting that overflow is not a regulatory signal in this model.Although the adaptive response has been shown to exist in terms of urinary excretion at the apical surface in adult rats, little is known about the response of these animals to taurine deprivation in the presence of phosphate depletion. Herein, we ...

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Membrane Fluidity and Phospholipid Composition in Relation to Sulfur Amino Acid Intake in Brush Border Membranes of Rat Kidney

Cited by 9 publications

References 29 publications

The taurine transporter: mechanisms of regulation

The taurine transporter: mechanisms of regulation

Cell membrane fluidity in the intact kidney proximal tubule measured by orientation-independent fluorescence anisotropy imaging

Adaptation to Taurine Deprivation in the Phosphate-Depleted Rat

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