Cytosolic proteome of Kluyveromyces lactis affected by the multidrug resistance regulating transcription factor KlPdr1p

[EN]Multidrug resistance (MDR), a ubiquitous phenomenon conserved from bacteria to humans, causes serious problems in the treatment of human cancers and infections of bacterial and fungal origin. The development of MDR in yeast is frequently associated with gain-of-function mutations in the Zn(2)Cys(6) transcription factors activating the expression of several plasma membrane exporters. In the aerobic yeast Kluyveromyces lactis the Zn(2)Cys(6) transcription factor KlPdr1p is involved in the control of multidrug resistance. The aim of the present study was to identify the changes in K. lactis proteome of the Klpdr1Δ deletion mutant compared with the wild-type expressing the KlPDR1 gene from a multicopy plasmid. A total of 15 differentially expressed proteins, out of 20 spots with different intensities detected, were identified. In the Klpdr1Δ deletion mutant, the increase in the abundance of proteins involved in carbohydrate metabolism (mainly glycolysis/gluconeogenesis) was observed. Most of the proteins overexpressed in the wild type strain containing the KlPDR1 gene on multicopy plasmid were involved in the stress defence and redox homeostasis. The results indicate a close connection between MDR and oxidative stress response associated with the post-translational mechanisms regulating the levels of active forms of proteins involved in K. lactis MDR

Insight into the Kluyveromyces lactis Pdr1p regulon

The overexpression of efflux pumps is an important mechanism leading to the development of multidrug resistance phenomenon. The transcription factor KlPdr1p, belonging to the Zn2Cys6 family, is a central regulator of efflux pump expression in Kluyveromyces lactis. To better understand how KlPDR1-mediated drug resistance is achieved in K. lactis, we used DNA microarrays to identify genes whose expression was affected by deletion or overexpression of the KlPDR1 gene. Eighty-nine targets of the KlPDR1 were identified. From those the transcription of 16 genes was induced in the transformant overexpressing KlPDR1* and simultaneously repressed in the Klpdr1â deletion mutant. Almost all of these genes contain putative binding motifs for the AP-1 like transcription factors in their promoters. Furthermore, we studied the possible interplay between KlPdr1p and KlYap1p transcription factors. Our results show that KlYap1p does not significantly contribute to the regulation of the KlPDR1 gene expression in the presence of azoles. However, KlPDR1 expression markedly increased in the presence of hydrogen peroxide and hinged upon the presence of KlYap1p. Our results show that although both KlPdr1p andKlYap1p transcription factors are involved in the control of K. lactis multidrug resistance further studies will be needed to determine their interplay .The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author