Vacuolar Cation/H+ Antiporters of Saccharomyces cerevisiae
Vacuolar Cation/H+ Antiporters of Saccharomyces cerevisiae
复制标题
DOI：
10.1074/jbc.m110.116590
复制
发表时间：
2010-10-29
影响因子：
4.8
通讯作者：
Venema, Kees
中科院分区：
文献类型：
--
作者：
Cagnac, Olivier;Nieves Aranda-Sicilia, Maria;Venema, Kees
我们以前证明，酿酒酵母vnx 1三角洲突变株显示几乎全部损失的Na+和K+/H+逆向转运蛋白活性的空泡富集部分。然而，使用不同的体外运输条件下，我们能够揭示额外的K+/H+反向转运蛋白的活性。通过破坏编码可能参与vnx 1突变株的转运蛋白的基因，我们确定Vcx 1 p负责这种活性。通过vnx 1 Delta vcx 1 Delta nhx 1 Delta三重突变体与Vcx 1 p及其失活突变体Vcx 1 p-H303 A的互补进一步证实了该结果。与Vcx 1 p催化的Ca ~（2+）/H ~+逆向转运蛋白活性相似，Cd ~（2+）对K ~（2+）/H ~+逆向转运蛋白活性有强烈的抑制作用，Zn ~（2+）对K ~（2+）/H ~+逆向转运蛋白活性的抑制作用较小。与先前观察到的NHX 1或VNX 1不同，在高浓度K+存在下，VCX 1过表达仅略微改善酵母菌株AXT 3的生长，并且对潮霉素敏感性没有影响。亚细胞定位表明，Vcx 1 p和Vnx 1 p的目标是液泡膜，而Nhx 1 p的目标是prevacuoles。Nhx 1 p，Vnx 1 p，和Vcx 1 p在液泡中积累的单价阳离子的相对重要性进行了讨论。
We previously demonstrated that Saccharomyces cerevisiae vnx1 Delta mutant strains displayed an almost total loss of Na+ and K+/H+ antiporter activity in a vacuole-enriched fraction. However, using different in vitro transport conditions, we were able to reveal additional K+/H+ antiporter activity. By disrupting genes encoding transporters potentially involved in the vnx1 mutant strain, we determined that Vcx1p is responsible for this activity. This result was further confirmed by complementation of the vnx1 Delta vcx1 Delta nhx1 Delta triple mutant with Vcx1p and its inactivated mutant Vcx1p-H303A. Like the Ca2+/H+ antiporter activity catalyzed by Vcx1p, the K+/H+ antiporter activity was strongly inhibited by Cd2+ and to a lesser extend by Zn2+. Unlike as previously observed for NHX1 or VNX1, VCX1 overexpression only marginally improved the growth of yeast strain AXT3 in the presence of high concentrations of K+ and had no effect on hygromycin sensitivity. Subcellular localization showed that Vcx1p and Vnx1p are targeted to the vacuolar membrane, whereas Nhx1p is targeted to prevacuoles. The relative importance of Nhx1p, Vnx1p, and Vcx1p in the vacuolar accumulation of monovalent cations will be discussed.