Expression of Taurine Transporter and its Regulation by Diet in Xenopus laevis Oocytes Following Injection of Rat Kidney Cortex mRNA

1994 ◽  
pp. 121-130 ◽  
Author(s):  
Xiaobin Han ◽  
Russell W. Chesney
Keyword(s):  
Xenopus Laevis ◽  
Rat Kidney ◽  
Kidney Cortex ◽  
Xenopus Laevis Oocytes ◽  
Taurine Transporter ◽  
Rat Kidney Cortex

scholarly journals Expression of a rat renal sodium-dependent dicarboxylate transporter in Xenopus oocytes

1994 ◽  
Vol 297 (1) ◽  
pp. 35-39 ◽  
Author(s):  
J Steffgen ◽  
S Kienle ◽  
F Scheyerl ◽  
H E Franz
Keyword(s):  
Xenopus Oocytes ◽  
Rat Kidney ◽  
Ph Dependence ◽  
Hill Coefficient ◽  
Kidney Cortex ◽  
Xenopus Laevis Oocytes ◽  
Rat Kidney Cortex ◽  
Maximal Activation ◽  
Sodium Dependent ◽  
In Trans

Microinjection of mRNA isolated from rat kidney cortex into Xenopus laevis oocytes resulted in the expression of a Na(+)-dependent dicarboxylate transporter, as detected by uptake measurements with [14C]succinate as substrate. The expressed transporter showed an S-shaped Na(+)-dependence with half-maximal activation at 19-21 mM Na+ and a Hill coefficient between 2 and 3. Endogenous succinate uptake was not Na(+)-dependent. Na(+)-stimulated succinate uptake in mRNA-injected oocytes exhibited a maximum at pH 7.5, whereas endogenous Na(+)-independent transporter was fastest at pH 8.5. The expressed dicarboxylate transporter also differed from the endogenous transporter in its sensitivity to citrate as well as dicarboxylates in trans and cis configurations. The expressed transporter resembled the renal basolateral transporter, especially with respect to affinity for succinate (Km 28 microM), activation by Na+, pH-dependence and substrate specificity. After injection of size-fractionated mRNA, succinate uptake was expressed by mRNA of 2-3 kb. Our results suggest expression of the basolateral Na(+)-dependent dicarboxylate transporter after injection of mRNA from rat kidney into Xenopus oocytes.

Rat kidney MAP17 induces cotransport of Na-mannose and Na-glucose inXenopus laevisoocytes

2003 ◽  
Vol 285 (4) ◽  
pp. F799-F810 ◽  
Author(s):  
Tatiana Blasco ◽  
José J. Aramayona ◽  
Ana I. Alcalde ◽  
Julia Catalán ◽  
Manuel Sarasa ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Transport System ◽  
Rat Kidney ◽  
Kidney Cortex ◽  
Seminiferous Tubules ◽  
Xenopus Laevis Oocytes ◽  
Breast Carcinomas ◽  
Rat Kidney Cortex ◽  
Molecular Identity ◽  
Dependent Transport

Renal reabsorption is the main mechanism that controls mannose homeostasis. This takes place through a specific Na-coupled uphill transport system, the molecular identity of which is unknown. We prepared and screened a size-selected rat kidney cortex cDNA library through the expression of mannose transport in Xenopus laevis oocytes. We have identified a membrane protein that induces high-affinity and specific Na-dependent transport of d-mannose and d-glucose in X. laevis oocytes, most likely through stimulation of the capacity of an endogenous transport system of the oocyte. Sequencing has revealed that the cDNA encodes the counterpart of the human membrane-associated protein MAP17, previously known by its overexpression in renal, colon, lung, and breast carcinomas. We show that MAP17 is a 12.2-kDa nonglycosylated membrane protein that locates to the brush-border plasma membrane and the Golgi apparatus of transfected cells and that it is expressed in the proximal tubules of the kidney cortex and in the spermatids of the seminiferous tubules. It spans twice the cell membrane, with both termini inside the cell, and seems to form homodimers through intracellular Cys55, a residue also involved in transport expression. MAP17 is responsible for mannose transport expression in oocytes by rat kidney cortex mRNA. The induced transport has the functional characteristics of a Na-glucose cotransporter (SGLT), because d-glucose and α-methyl-d-glucopyranoside are also accepted substrates that are inhibited by phloridzin. The corresponding transporter from the proximal tubule remains to be identified, but it is different from the known mammalian SGLT-1, -2, and -3.

Interaction with grp58 increases activity of the thiazide-sensitive Na-Cl cotransporter

2002 ◽  
Vol 282 (3) ◽  
pp. F424-F430 ◽  
Author(s):  
Bruce Wyse ◽  
Nawb Ali ◽  
David H. Ellison
Keyword(s):  
Rat Kidney ◽  
Glucose Deprivation ◽  
Kidney Cortex ◽  
Xenopus Laevis Oocytes ◽  
Rat Kidney Cortex ◽  
Sodium Uptake ◽  
Sodium Chloride Cotransporter ◽  
Important Interaction ◽  
Hybrid Screening

The thiazide-sensitive sodium-chloride cotransporter (NCC) is expressed by distal convoluted tubule cells of the mammalian kidney. We used yeast two-hybrid screening to identify that glucose-regulated protein 58 (grp58), a protein induced by glucose deprivation, binds to the COOH terminus of the NCC. Immunoprecipitation of rat kidney cortex homogenates using a guinea pig anti-NCC antibody confirmed that grp58 associates with the NCC in vivo. Northern blots indicated that grp58 is highly expressed in rat kidney cortex. Immunofluorescence showed that grp58 protein abundance in kidney is highest in epithelial cells of the distal nephron, where it colocalizes with NCC near the apical membrane. To determine whether this interaction has a functional significance, NCC and grp58 cRNA were coexpressed in Xenopus laevis oocytes. In oocytes overexpressing grp58, sodium uptake was increased compared with control. Because oocytes express endogenous grp58, antisense experiments were performed to evaluate whether endogenous grp58 affected NCC activity in oocytes. Sodium uptake was lower in oocytes injected with both antisense grp58 cRNA and sense NCC compared with sense NCC oocytes. Western blot analysis did not show any effect of grp58 expression on processing of the NCC. These data indicate a novel, functionally important interaction between grp58 and the NCC in rat kidney cortex.

scholarly journals Increase of Na/Pi-cotransport encoding mRNA in response to low Pi diet in rat kidney cortex.

1994 ◽  
Vol 269 (9) ◽  
pp. 6637-6639
Author(s):  
A. Werner ◽  
S.A. Kempson ◽  
J. Biber ◽  
H. Murer
Keyword(s):  
Rat Kidney ◽  
Kidney Cortex ◽  
Rat Kidney Cortex

Cytochrome P-450K of rat kidney cortex microsomes: Further studies on its interaction with fatty acids

1973 ◽  
Vol 158 (2) ◽  
pp. 597-604 ◽  
Author(s):  
Åke Ellin ◽  
Sten Orrenius ◽  
Åke Pilotti ◽  
Carl-Gunnar Swahn
Keyword(s):  
Fatty Acids ◽  
Rat Kidney ◽  
Kidney Cortex ◽  
Rat Kidney Cortex

scholarly journals Studies on the orientation of brush-border membrane vesicles

1978 ◽  
Vol 172 (1) ◽  
pp. 57-62 ◽  
Author(s):  
W Haase ◽  
A Schäfer ◽  
H Murer ◽  
R Kinne
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Rat Kidney ◽  
Freeze Fracture ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Immunological Methods ◽  
Kidney Cortex ◽  
Asymmetric Distribution ◽  
Rat Kidney Cortex

Orientation of rat renal and intestinal brush-border membrane vesicles was studied with two independent methods: electron-microscopic freeze-fracture technique and immunological methods. With the freeze-fracture technique a distinct asymmetric distribution of particles on the two membrane fracture faces was demonstrated; this was used as a criterion for orientation of the isolated membrane vesicles. For the immunological approach the accessibility or inaccessibility of aminopeptidase M localized on the outer surface of the cell membrane to antibodies was used. With both methods we showed that the brush-border membrane vesicles isolated from rat kidney cortex and from rat small intestine for transport studies are predominantly orientated right-side out.

Endogenous Kallikrein Inhibitor in Rat Kidney Cortex-Effect of Glucocorticoid Administration

1986 ◽  
pp. 361-365 ◽  
Author(s):  
Kodo Ito ◽  
Kenichi Yamada ◽  
Setsuko Yoshida ◽  
Keiji Hasunuma ◽  
Yasushi Tamura ◽  
...  
Keyword(s):  
Rat Kidney ◽  
Kidney Cortex ◽  
Rat Kidney Cortex ◽  
Kallikrein Inhibitor ◽  
Glucocorticoid Administration

Identification of an apical \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{Cl}^{-}{/}\mathrm{HCO}_{3}^{-}\) \end{document} exchanger in rat kidney proximal tubule

2003 ◽  
Vol 285 (3) ◽  
pp. C608-C617 ◽  
Author(s):  
Snezana Petrovic ◽  
Liyun Ma ◽  
Zhaohui Wang ◽  
Manoocher Soleimani
Keyword(s):  
Proximal Tubule ◽  
Apical Membrane ◽  
Rat Kidney ◽  
Proximal Tubules ◽  
Immunocytochemical Staining ◽  
Kidney Cortex ◽  
Rat Kidney Cortex ◽  
Kidney Proximal Tubule ◽  
Anion Transporter

SLC26A6 (or putative anion transporter 1, PAT1) is located on the apical membrane of mouse kidney proximal tubule and mediates [Formula: see text] exchange in in vitro expression systems. We hypothesized that PAT1 along with a [Formula: see text] exchange is present in apical membranes of rat kidney proximal tubules. Northern hybridizations indicated the exclusive expression of SLC26A6 (PAT1 or CFEX) in rat kidney cortex, and immunocytochemical staining localized SLC26A6 on the apical membrane of proximal tubules, with complete prevention of the labeling with the preadsorbed serum. To examine the functional presence of apical [Formula: see text] exchanger, proximal tubules were isolated, microperfused, loaded with the pH-sensitive dye BCPCF-AM, and examined by digital ratiometric imaging. The pH of the perfusate and bath was kept at 7.4. Buffering capacity was measured, and transport rates were calculated as equivalent base flux. The results showed that in the presence of basolateral DIDS (to inhibit [Formula: see text] cotransporter 1) and apical EIPA (to inhibit Na+/H+ exchanger 3), the magnitude of cell acidification in response to addition of luminal Cl– was ∼5.0-fold higher in the presence than in the absence of [Formula: see text]. The Cl–-dependent base transport was inhibited by ∼61% in the presence of 0.5 mM luminal DIDS. The presence of physiological concentrations of oxalate in the lumen (200 μM) did not affect the [Formula: see text] exchange activity. These results are consistent with the presence of SLC26A6 (PAT1) and [Formula: see text] exchanger activity in the apical membrane of rat kidney proximal tubule. We propose that SLC26A6 is likely responsible for the apical [Formula: see text] (and Cl–/OH–) exchanger activities in kidney proximal tubule.

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