Protonophore FCCP provides fitness advantage to PDR-deficient yeast cells Kseniia V. Galkina 1 & Joseph M. Finkelberg 2 & Olga V. Markova 1 & Aglaia V. Azbarova 1,2 & Atanu Banerjee 3 & Sonam Kumari 4 & Svyatoslav S. Sokolov 1 & Fedor F. Severin 1 & Rajendra Prasad 3 & Dmitry A. Knorre 1,5 Received: 17 May 2020 /Accepted: 6 August 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract Pleiotropic drug resistance (PDR) plasma membrane transporters mediate xenobiotic efflux from the cells and thereby help pathogenic microorganisms to withstand antimicrobial therapies. Given that xenobiotic efflux is an energy-consuming process, cells with upregulated PDR can be sensitive to perturbations in cellular energetics. Protonophores dissipate proton gradient across the cellular membranes and thus increase ATP spendings to their maintenance. We hypothesised that chronic exposure of yeast cells to the protonophores can favour the selection of cells with inactive PDR. To test this, we measured growth rates of the wild type Saccharomyces cerevisiae and PDR-deficient Δpdr1Δpdr3 strains in the presence of protonophores carbonyl cyanide-p- trifluoromethoxyphenylhydrazone (FCCP), pentachlorophenol (PCP) and niclosamide (NCA). Although the protonophore- induced respiration rates of these two strains were similar, the PDR-deficient strain outperformed the control one in the growth rate on non-fermentable carbon source supplemented with low concentrations of FCCP. Thus, active PDR can be deleterious under conditions of partially uncoupled oxidative-phosphorylation. Furthermore, our results suggest that tested anionic protonophores are poor substrates of PDR-transporters. At the same time, protonophores imparted azole tolerance to yeasts, pointing that they are potent PDR inducers. Interestingly, protonophore PCP led to a persistent increase in the levels of a major ABC-transporter Pdr5p, while azole clotrimazole induced only a temporary increase. Together, our data provides an insight into the effects of the protonophores in the eukaryotes at the cellular level and support the idea that cells with activated PDR can be selected out upon conditions of energy limitations. Keywords Protonophores . Uncouplers . Multiple drug resistance . Niclosamide . Drug interactions Introduction Microbial drug resistance is an expanding problem for healthcare and agriculture (Fisher et al. 2018; Van Boeckel et al. 2019). While drug-resistant bacteria produce a major part of the pressure on the healthcare system (Roope et al. 2019), drug-resistant fungi are a specific threat to immuno- suppressed patients (Kontoyiannis and Lewis 2002). Tens of thousands clinical cases are attributed to infections caused by drug-resistant Candida species (Centers for Disease Control and Prevention (U.S.) 2019). In yeasts, drug resistance is usually mediated by plasma membrane transporters with broad substrate specificity (Tsao et al. 2009; Wasi et al. 2019; Zhang et al. 2020). These pleio- tropic drug resistance (PDR) transporters efflux toxic com- pounds from yeast cytoplasm at the cost of ATP hydrolysis (ABC-transporters) or proton translocation in case of MFS transporters (Panwar et al. 2008). Moreover, some ABC trans- porters hydrolyse ATP even during futile catalytic cycles Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10863-020-09849-1) contains supplementary material, which is available to authorized users. * Dmitry A. Knorre knorre@belozersky.msu.ru 1 Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskiye Gory 1–40, Moscow 119991, Russia 2 Faculty of Bioengineering and Bioinformatics, Moscow State University, Leninskiye Gory 1–73, Moscow 119991, Russia 3 Amity Institute of Biotechnology and Amity Institute of Integrative Sciences and Health, Amity University Haryana, Amity Education Valley, Gurugram 122413, India 4 International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India 5 Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow 119991, Russia Journal of Bioenergetics and Biomembranes https://doi.org/10.1007/s10863-020-09849-1