Large Mg(2+)-dependent currents are associated with the increased expression of ALR1 in Saccharomyces cerevisiae.
Large Mg(2+)-dependent currents are associated with the increased expression of ALR1 in Saccharomyces cerevisiae.
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DOI：
10.1111/j.1574-6968.2002.tb11311.x
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发表时间：
2002-08
影响因子：
2.1
通讯作者：
G. J. Liu;Donald K. Martin;R. Gardner;P. Ryan
中科院分区：
文献类型：
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作者：
G. J. Liu;Donald K. Martin;R. Gardner;P. Ryan
酿酒酵母中的两个基因ALR1和ALR2编码的蛋白被认为与Mg（2+）摄取有关。本研究支持ALR1的这一作用，并提供了该蛋白的第一个电生理特征。采用膜片钳技术测定了野生型菌株、alr1、alr2双突变体（CM66）和过表达alr1基因的双突变体（CM66+ alr1）制备的原生质体的全细胞离子电流。当沐浴液中含有50 mM Mg（2+）时，CM66+ALR1原生质体内电流在-150 mV时平均为-264+/-48 pA。在野生型和CM66原生质体中测量到的内向电流要小五倍以上。当移液液中Mg（2+）为主要阳离子时，在CM66+ALR1原生质体中也检测到时间依赖的外向电流，这表明ALR1可以促进Mg（2+）的外排和吸收。我们得出结论，ALR1基因编码转运蛋白。依赖于Mg（2+）的大幅度电流表明ALR1可以作为阳离子通道发挥作用。
Two genes in Saccharomyces cerevisiae, ALR1 and ALR2, encode proteins putatively involved in Mg(2+) uptake. The present study supports this role for ALR1 and provides the first electrophysiological characterisation of this protein. The patch-clamp technique was used to measure whole-cell ion currents in protoplasts prepared from the wild-type strain, the alr1 alr2 double mutant (CM66), and the double mutant over-expressing the ALR1 gene (CM66+ALR1). With 50 mM Mg(2+) in the bathing solution, the inward current in protoplasts of CM66+ALR1 averaged -264+/-48 pA at -150 mV. Inward currents measured in the wild-type and CM66 protoplasts were more than five-fold smaller. When Mg(2+) was the major cation in the pipette solution, time-dependent outward currents were also detected in CM66+ALR1 protoplasts suggesting ALR1 can facilitate Mg(2+) efflux as well as uptake. We conclude that the ALR1 gene encodes a transport protein. The large magnitude of the Mg(2+)-dependent currents suggests that ALR1 could function as a cation channel.