vacuolar h+-translocation pyrophosphatase (v-ppase) and na+/h+ antiporter (v-na+/h+) are important transporters in plant cells and have essential roles against abiotic stresses. in this study, the effects of salt stress were surveyed on the transcription of v-ppase pump and na+/h+ antiporter genes at early times of nacl treatment in roots of halophytic grass leptochloa fusca through the real ti...

To examine the role of protein kinase C as a chronic regulator of proximal tubule Na/H antiporter activity, the effect of phorbol 12-myristate 13-acetate (PMA) on the Na/H antiporter was studied in cultured proximal tubule cells. Short-term activation of protein kinase C by 5 min exposure to PMA caused an acute increase in Na/H antiporter activity that was not prevented by cycloheximide or acti...

This study characterized the activation of the regulatory activity of the Na+/H+ antiporter during fertilization of hamster embryos. Hamster oocytes appeared to lack any mechanism for the regulation of intracellular pH in the acid range. Similarly, no Na+/H+ antiporter activity could be detected in embryos that were collected from the reproductive tract between 1 and 5 h post-egg activation (PE...

Renal cortical tubules consist of polarized epithelial cells where Na/H antiport activity has been demonstrated on the apical and/or basolateral membrane. Apical Na/H antiport activity plays an important role in transcellular bicarbonate (HCO3) reabsorption, whereas basolateral Na/H antiport activity could be involved in transcellular HCO3secretion as well as cell volume and pH control. To dete...

a significant portion of the world’s cultivated land is affected by salinity that reduces crop productivity in these areas. breeding for salt tolerance is one of the important strategies to overcome this problem. recently, genetic engineering is becoming a promising approach to improving salt tolerance. in order to improve the yield performance of canola in saline soils, we transformed canola w...

The mammalian proximal tubule is an important mediator of the renal adaptive response to systemic acidosis. In chronic metabolic and respiratory acidosis the bicarbonate reabsorptive (or proton secretory) capacity is increased. This increase is mediated, at least in part, by an increase in Vmax of the luminal Na/H antiporter. To determine whether this adaptation involves increased mRNA expressi...

We conducted an analysis of the topology of AtNHX1, an Arabidopsis thaliana vacuolar Na+/H+ antiporter. Several hydrophilic regions of the antiporter were tagged with a hemagglutinin epitope, and protease protection assays were conducted to determine the membrane topology of the antiporter by using yeast as a heterologous expression system. The overall structure of AtNHX1 is distinct from the h...

The amiloride-sensitive Na + /H + antiporter in defolliculated oocytes of Xenopus laevis was characterized by measurements of H Na + influx and apparent H + efflux. Uptake of ^Na"" was linear over a 90-min incubation period and was inhibited approximately 80% with 5xlO~moll~ amiloride. Amiloride-sensitive sodium uptake was reduced following collagenase treatment or oocyte aging. Ko 5 for amilor...

To examine the mechanisms by which endothelin (ET) regulates the Na/H antiporter isoform, NHE-3, OKP cells were stably transfected with ET A and ET B receptor cDNA. In cells overexpressing ET B , but not ET A receptors, ET-1 increased Na/H antiporter activity (J Na/H ). This effect was inhibited by a nonselective endothelin receptor blocker and by a selective ET B receptor blocker but was not i...

To clone the gene for the human Na+/H+ antiporter, we first constructed a stable mouse LTK- cell line (LAP1) lacking Na+/H+ antiport activity. Second, we devised a selective technique based on acid killing that specifically sorts out cells expressing low levels of Na+/H+ antiport activity from a population of antiporter-deficient cells (AP-). LAP1 cells (TK- and AP-) were cotransformed with hum...