Activity of the Kluyveromyces lactis Pdr5 multidrug transporter is modulated by the sit4 protein phosphatase
Activity of the Kluyveromyces lactis Pdr5 multidrug transporter is modulated by the sit4 protein phosphatase
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DOI：
10.1128/jb.183.13.3939-3948.2001
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发表时间：
2001-07-01
影响因子：
3.2
通讯作者：
Chen, XJ
中科院分区：
文献类型：
--
作者：
Chen, XJ
翻译后修饰在调节 ATP 结合盒 (ABC) 转运蛋白活性中的可能作用尚未明确。本研究从芽殖酵母乳酸克鲁维酵母中分离出药物外排ABC转运蛋白基因KlPDR5，发现编码的KlPdr5药物泵受到ZA型相关Ser/Thr蛋白磷酸酶Sit4p的翻译后调节。 KlPdr5 转运蛋白是一种由 1,525 个氨基酸组成的蛋白质，与其酿酒酵母对应物 ScPdr5p 具有 63.8% 的序列同一性。 KlPDR5 基因的过度表达会导致对寡霉素、抗霉素、益康唑和酮康唑的耐药性，而 KlPDR5 等位基因被破坏的细胞对药物过敏，并且阴离子荧光染料罗丹明 123 流出的能力下降。研究发现，KlPDR5 的染色体破坏消除了与 sat4 突变相关的耐药表型，并且通过在sit4突变体中过度表达KlPDR5可以产生对药物的协同高耐药性。这些数据强烈表明，sit4 突变体的多重耐药表型是通过负向调节 KlPdr5p 的活性介导的。由于 KlPDR5 的转录水平和 KlPdr5p 的稳态水平不受 SIT4 突变的显着影响，因此 Sit tp 的调节似乎是翻译后过程。
A possible role for posttranslational modifications in regulating the activity of ATP-binding cassette (ABC) transporters has not been well established. In this study, the drug efflux ABC transporter gene KlPDR5 was isolated from the budding yeast Kluyveromyces lactis, and it was found that the encoded KlPdr5 drug pump is posttranslationally regulated by the type ZA-related Ser/Thr protein phosphatase, Sit4p. The KlPdr5 transporter is a protein of 1,525 amino acids sharing 63.8% sequence identity with its Saccharomyces cerevisiae counterpart, ScPdr5p. Overexpression of the KlPDR5 gene confers resistance to oligomycin, antimycin, econazole, and ketoconazole, whereas cells with a disrupted allele of KlPDR5 are hypersensitive to the drugs and have a decreased capacity to carry out efflux of the anionic fluorescent dye rhodamine 123. It was found that a chromosomal disruption of KlPDR5 abolishes the drug-resistant phenotype associated with sit4 mutations and that a synergistic hyperresistance to the drugs can be created by overexpressing KlPDR5 in sit4 mutants. These data strongly indicate that the multidrug-resistant phenotype of sit4 mutants is mediated by negatively modulating the activity of KlPdr5p. As the transcriptional level of KlPDR5 and the steady-state level of KlPdr5p are not significantly affected by mutations in SIT4, the regulation by Sit tp appears to be a posttranslational process.