In baker's yeast (Saccharomyces cerevisiae), Trk1, a member of the superfamily of K-transporters (SKT), is the main K+ uptake system under conditions when its concentration in the environment is low. Structurally, Trk1 is made up of four domains, each similar and homologous to a K-channel α subunit. Because most K-channels are proteins containing four channel-building α subunits, Trk1 could be functional as a monomer. However, related SKT proteins TrkH and KtrB were crystallised as dimers, and for Trk1, a tetrameric arrangement has been proposed based on molecular modelling. Here, based on Bimolecular Fluorescence Complementation experiments and single-molecule fluorescence microscopy combined with molecular modelling; we provide evidence that Trk1 can exist in the yeast plasma membrane as a monomer as well as a dimer. The association of monomers to dimers is regulated by the K+ concentration.

• Klíčová slova
• K+ translocation, MD simulation, Saccharomyces cerevisiae, bimolecular fluorescence complementation, dimerisation, molecular modelling,
• MeSH
• biologický transport MeSH
• buněčná membrána metabolismus   MeSH
• draslík metabolismus   MeSH
• fungální proteiny metabolismus   MeSH
• proteiny přenášející kationty * genetika   metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny * genetika   metabolismus   MeSH
• Saccharomyces cerevisiae metabolismus   MeSH
• translokace genetická MeSH
• transportní proteiny metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• draslík MeSH
• fungální proteiny MeSH
• proteiny přenášející kationty * MeSH
• Saccharomyces cerevisiae - proteiny * MeSH
• transportní proteiny MeSH
• TRK1 protein, S cerevisiae MeSH Prohlížeč

The maintenance of potassium homeostasis is crucial for all types of cells, including Candida glabrata. Three types of plasma-membrane systems mediating potassium influx with different transport mechanisms have been described in yeasts: the Trk1 uniporter, the Hak cation-proton symporter and the Acu ATPase. The C. glabrata genome contains only one gene encoding putative system for potassium uptake, the Trk1 uniporter. Therefore, its importance in maintaining adequate levels of intracellular potassium appears to be critical for C. glabrata cells. In this study, we first confirmed the potassium-uptake activity of the identified gene's product by heterologous expression in a suitable S. cerevisiae mutant, further we generated a corresponding deletion mutant in C. glabrata and analysed its phenotype in detail. The obtained results show a pleiotropic effect on the cell physiology when CgTRK1 is deleted, affecting not only the ability of trk1Δ to grow at low potassium concentrations, but also the tolerance to toxic alkali-metal cations and cationic drugs, as well as the membrane potential and intracellular pH. Taken together, our results find the sole potassium uptake system in C. glabrata cells to be a promising target in the search for its specific inhibitors and in developing new antifungal drugs.

• MeSH
• buněčná membrána metabolismus   MeSH
• Candida glabrata metabolismus   fyziologie   MeSH
• draslík metabolismus   MeSH
• homeostáza fyziologie   MeSH
• iontový transport fyziologie   MeSH
• kationty metabolismus   MeSH
• membránové potenciály fyziologie   MeSH
• proteiny přenášející kationty metabolismus   MeSH
• regulace genové exprese u hub fyziologie   MeSH
• Saccharomyces cerevisiae metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• draslík MeSH
• kationty MeSH
• proteiny přenášející kationty MeSH
• Trk1 protein, Candida albicans MeSH Prohlížeč