CHANGES INDUCED IN THE PERMEABILITY BARRIER OF THE YEAST PLASMA-MEMBRANE BY CUPRIC ION
CHANGES INDUCED IN THE PERMEABILITY BARRIER OF THE YEAST PLASMA-MEMBRANE BY CUPRIC ION
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DOI：
10.1128/jb.170.6.2676-2682.1988
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发表时间：
1988-06-01
影响因子：
3.2
通讯作者：
ANRAKU, Y
中科院分区：
文献类型：
--
作者：
OHSUMI, Y;KITAMOTO, K;ANRAKU, Y
一个特定的效果，铜+引发选择性的变化，完整的酿酒酵母细胞的渗透性。当将100 μ M CuCl 2加入到在低离子强度缓冲液中的细胞悬浮液中时，细胞质膜的渗透屏障在25 ℃下2分钟内丧失。C.氨基酸的释放是部分的，并且释放的氨基酸的组成与保留在细胞中的氨基酸的组成不同。大部分谷氨酸被释放，但精氨酸主要保留在细胞中。加入CuCl 2后，细胞内K+迅速释放，但总K+的30%保留在细胞内。这些和其他观察结果表明，Cu ~（2+）引起质膜渗透屏障的选择性病变，但不影响血管膜的渗透性。这些选择性的变化不诱导的其他二价阳离子测试。建立了一种新的、简单的Cu ~（2+）处理差异提取液泡和胞质氨基酸库的方法。当Ca ~（2+）加入到Cu ~（2+）处理的细胞中时，大量的Ca ~（2+）被螯合到液泡中，并在液泡中形成Ca ~（2+）-多磷酸盐复合物，Cu ~（2+）处理的细胞也表现出对碱性氨基酸和S-腺苷甲硫氨酸的摄取增强。这些底物的运输表现出饱和动力学与低亲和力，反映了液泡运输过程中原位。在Cu ~（2+）处理下，K ~+从胞液中选择性渗漏，在液泡膜上形成一个大的K ~+浓度梯度，并产生一个负膜电位，这可能是液泡吸收带正电荷物质的驱动力。Cu ~（2+）处理提供了一个有用的原位方法，用于研究质膜溶质池的形成机制和跨膜转运现象。
A specific effect of Cu2+ eliciting selective changes in the permeability of intact Saccharomyces cerevisiae cells is described. When 100 .mu.M CuCl2 was added to a cell suspension in a buffer of low ionic strength, the permeability barrier of the plasma membranes of the cells was lost within 2 min at 25.degree. C. The release of amino acids was partial, and the composition of amino acids released was different from that of those retained in the cells. Mostly glutamate was released, but arginine was mainly retained in the cells. Cellular K+ was released rapidly after CuCl2 addition, but 30% of the total K+ was retained in the cells. These and other observations suggested that Cu2+ caused selected lesions of the permeability barrier of the plasma memberane but did not affect the permeability of the vasucolar membrane. These selective changes were not induced by the other divalent cations tested. A novel and simple method for differential extraction of vacuolar and cytosolic amino acid pools by Cu2+ treatment was established. When Ca2+ was added to Cu2+-treated cells, a large amount of Ca2+ was sequestered into vacuoles, with formation of an inclusion of a Ca2+-polyphosphate complex in the vaculoes, Cu2+-treated cells also showed enhanced uptake of basic amino acids and S-adenosylmethionine. The transport of these substrates showed saturable kinetics with low affinities, reflecting the vacuolar transport process in situ. With Cu2+ treatment, selective leakage of K+ from the cytosolic compartment appears to creat a large concentration gradient of K+ across the vacuolar membrane and generates an inside-negative membrane potential, which may provide a driving force of uptake of positively charged substances into vacuoles. Cu2+ treatment provides a useful in situ method for investigating the mechanisms of differenetial solute pool formation and specific transport phenomena across the vacuolar membrane.