ATP-dependent transport of reduced glutathione in yeast secretory vesicles.
ATP-dependent transport of reduced glutathione in yeast secretory vesicles.
复制标题
酵母分泌囊泡中还原型谷胱甘肽的 ATP 依赖性转运。
DOI：
10.1042/bj3340723
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
Ballatori,N
中科院分区：
文献类型：
--
作者：
Rebbeor,JF;Connolly,GC;Dumont,ME;Ballatori,N
Turnover of cellular reduced glutathione (GSH) is accomplished predominantly by export into the extracellular space; however, the plasma membrane transport mechanisms that mediate GSH efflux are not well characterized. The present study examined GSH transport using secretory vesicles isolated from thesec6-4 mutant strain ofSaccharomyces cerevisiae. In contrast with studies in mammalian membrane vesicles, GSH transport in yeast secretory vesicles was mediated largely by an ATP-dependent, low-affinity pathway (Km19±5 mM). ATP-dependent [3H]GSH transport wascis-inhibited by substrates of the yeast YCF1 transporter, including sulphobromophthalein, glutathione S-conjugates and the alkaloid verapamil, and was competitively inhibited byS-(2,4-dinitrophenyl)glutathione (DNP-SG). Similarly, GSH competitively inhibited ATP-dependent [3H]DNP-SG transport, with aKiof 18±2 mM, but had no effect on ATP-dependent [3H]taurocholate transport. ATP-dependent GSH transport was not affected by either membrane potential or pH-gradient uncouplers, but was inhibited by 4,4´-di-isothiocyanatostilbene-2,2´-disulphonate, probenecid and sulphinpyrazone, which are inhibitors of mrp1 and mrp2, mammalian homologues of the yeast YCF1 transporter. Western blot analysis of the secretory vesicle membrane fraction confirmed the presence of Ycf1p. These results provide the first direct evidence for low-affinity, ATP-dependent transport of GSH, and demonstrate that this ATP-dependent pathway displays kinetic characteristics similar to those of the yeast YCF1 transporter.
