The transmembrane domain 10 of the yeast Pdr5p ABC antifungal efflux pump determines both substrate specificity and inhibitor susceptibility
The transmembrane domain 10 of the yeast Pdr5p ABC antifungal efflux pump determines both substrate specificity and inhibitor susceptibility
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DOI：
10.1046/j.1365-2958.2000.01798.x
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发表时间：
2000-03-01
影响因子：
3.6
通讯作者：
Kuchler, K
中科院分区：
文献类型：
--
作者：
Egner, R;Bauer, BE;Kuchler, K
我们之前已经表明，Pdr5p ABC 转运蛋白跨膜结构域 10 (TMD10) 中的 S1360F 突变可调节底物特异性，同时导致 FK506 抑制作用的丧失。在本研究中，我们构建并表征了位于两亲性 Pdr5p TMD10 亲水面的 S1360F/A/T 和 T1364F/A/S 突变。 T1364F 突变导致 Pdr5p 介导的唑类和罗丹明 6G 耐药性降低。与S1360F一样，T1364F和T1364A突变体对FK506抑制几乎没有反应。然而，最值得注意的是，S1360A 突变增加了 FK506 抑制剂的敏感性，因为与野生型 Pdr5p 或无反应的 S1360F 变体相比，Pdr5p-S1360A 对 FK506 抑制高度敏感。因此，Pdr5p TMD10 决定了唑类底物特异性和对逆转剂的敏感性。这是真核 ABC 转运蛋白的首次演示，其中单个残基变化会导致抑制剂敏感性的降低或增加，具体取决于突变变化的性质。这些结果对于设计有效的逆转剂具有重要意义，该逆转剂可用于克服 ABC 转运蛋白过度表达介导的多药耐药性。
We have previously shown that a S1360F mutation in transmembrane domain 10 (TMD10) of the Pdr5p ABC transporter modulates substrate specificity and simultaneously leads to a loss of FK506 inhibition. In this study, we have constructed and characterized the S1360F/A/T and T1364F/A/S mutations located in the hydrophilic face of the amphipatic Pdr5p TMD10. A T1364F mutation leads to a reduction in Pdr5p-mediated azole and rhodamine 6G resistance. Like S1360F, the T1364F and T1364A mutants were nearly non-responsive to FK506 inhibition. Most remarkably, however, the S1360A mutation increases FK506 inhibitor susceptibility, because Pdr5p-S1360A is hypersensitive to FK506 inhibition when compared with either wild-type Pdr5p or the non-responsive S1360F variant. Hence, the Pdr5p TMD10 determines both azole substrate specificity and susceptibility to reversal agents. This is the first demonstration of a eukaryotic ABC transporter where a single residue change causes either a loss or a gain in inhibitor susceptibility, depending on the nature of the mutational change. These results have important implications for the design of efficient reversal agents that could be used to overcome multidrug resistance mediated by ABC transporter overexpression.