Rice Na+/H+-antiporter Nhx1 partially complements the alkali-metal-cation sensitivity of yeast strains lacking three sodium transporters
A triple mutant strain ofSaccharomyces cerevisiae lacking its own Na+-ATPases and Na+/H+ antiporters (ena1–4Δ nha1Δ nhx1Δ) was used for the expression of theOryza sativa NHX1 gene encoding a putative vacuolar Na+/H+ exchanger. Upon expression in yeast cells, theOsNhx1p is not a transport system specific only for sodium cations but it has a broad substrate specificity for at least four alkali metal cations (Na+, Li+, K+ and Rb+) and is able to substitute for the endogenous yeastScNhx1 antiporter. Its activity contributes to sequestration of alkali metal cations in intracellular vesicles.
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