Cnh1 Na+/H+ antiporter and Ena1 Na+-ATPase play different roles in cation homeostasis and cell physiology of Candida glabrata
Cnh1 Na+/H+ antiporter and Ena1 Na+-ATPase play different roles in cation homeostasis and cell physiology of Candida glabrata
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DOI：
10.1111/j.1567-1364.2010.00686.x
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发表时间：
2011-02-01
影响因子：
3.2
通讯作者：
Sychrova, Hana
中科院分区：
文献类型：
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作者：
Krauke, Yannick;Sychrova, Hana
酵母严格调节细胞内碱金属阳离子的浓度。在酿酒酵母中，Nha1 Na+/H+-逆向转运蛋白和 Ena1 Na+-ATP 酶介导有毒钠和过剩钾的外流。我们报告了光滑念珠菌 CgCnh1 和 CgEna1 同源物的特征。在酿酒酵母中表达时比较了它们的底物特异性和转运特性，并直接在光滑酿酒酵母中表征了它们的功能。 CgCnh1 逆向转运蛋白和 CgEna1 ATP 酶在酿酒酵母中表达时可转运钾和钠。 CgEna1p 完全补充了酿酒酵母自身 Na+-ATP 酶的缺乏，但 CgCnh1 反向转运蛋白的活性低于 ScNha1p。光滑念珠菌缺失突变体及其表型分析表明，尽管两种转运蛋白具有广泛的底物特异性，但它们在光滑念珠菌细胞中的功能并不相同。它们不同的生理作用也反映在它们的表达调节上，CgENA1 通过增加渗透压或钠浓度而高度上调，而 CgCNH1 是组成型表达。 Cnh1 逆向转运蛋白参与钾含量的调节，以及光滑 C. glabrata 细胞钠解毒过程中 Ena1 ATP 酶的调节。这种情况与酿酒酵母不同，其中 Nha1 逆向转运蛋白和 Ena ATP 酶共同参与 Na+ 解毒和 K+ 稳态的调节。
Yeasts tightly regulate their intracellular concentrations of alkali metal cations. In Saccharomyces cerevisiae, the Nha1 Na+/H+-antiporter and Ena1 Na+-ATPase, mediate the efflux of toxic sodium and surplus potassium. We report the characterization of Candida glabrata CgCnh1 and CgEna1 homologues. Their substrate specificity and transport properties were compared upon expression in S. cerevisiae, and their function characterized directly in C. glabrata. The CgCnh1 antiporter and the CgEna1 ATPase transport both potassium and sodium when expressed in S. cerevisiae. CgEna1p fully complements the lack of S. cerevisiae own Na+-ATPases but the activity of the CgCnh1 antiporter is lower than that of ScNha1p. Candida glabrata deletion mutants and analyses of their phenotypes revealed that though both transporters have a broad substrate specificity, their function in C. glabrata cells is not the same. Their differing physiological roles are also reflected in their regulation of expression, CgENA1 is highly upregulated by an increased osmotic pressure or sodium concentration, whereas CgCNH1 is expressed constitutively. The Cnh1 antiporter is involved in the regulation of potassium content and the Ena1 ATPase in sodium detoxification of C. glabrata cells. This situation differs from S. cerevisiae, where the Nha1 antiporter and Ena ATPases both participate together in Na+ detoxification and in the regulation of K+ homeostasis.