• MeSH
• aktivní transport * MeSH
• draslík metabolismus   MeSH
• králíci MeSH
• serotonin metabolismus   MeSH
• sodík metabolismus   MeSH
• trombocyty metabolismus   MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• draslík MeSH
• serotonin MeSH
• sodík MeSH

• MeSH
• biologický transport MeSH
• draslík metabolismus   MeSH
• genová knihovna MeSH
• komplementární DNA genetika   MeSH
• konformace proteinů MeSH
• membránové proteiny genetika   metabolismus   MeSH
• proteiny přenášející kationty * MeSH
• protony MeSH
• Schizosaccharomyces pombe - proteiny * MeSH
• Schizosaccharomyces genetika   metabolismus   MeSH
• sekvenční analýza DNA MeSH
• transportní proteiny genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• draslík MeSH
• komplementární DNA MeSH
• membránové proteiny MeSH
• proteiny přenášející kationty * MeSH
• protony MeSH
• Schizosaccharomyces pombe - proteiny * MeSH
• transportní proteiny MeSH
• trk1 protein, S pombe MeSH Prohlížeč

Candida krusei is a pathogenic yeast species that is phylogenetically outside both of the well-studied yeast groups, whole genome duplication and CUG. Like all other yeast species, it needs to accumulate high amounts of potassium cations, which are needed for proliferation and many other cell functions. A search in the sequenced genomes of nine C. krusei strains revealed the existence of two highly conserved genes encoding putative potassium uptake systems. Both of them belong to the TRK family, whose members have been found in all the sequenced genomes of species from the Saccharomycetales subclade. Analysis and comparison of the two C. krusei Trk sequences revealed all the typical features of yeast Trk proteins but also an unusual extension of the CkTrk2 hydrophilic N-terminus. The expression of both putative CkTRK genes in Saccharomyces cerevisiae lacking its own potassium importers showed that only CkTrk1 is able to complement the absence of S. cerevisiae's own transporters and provide cells with a sufficient amount of potassium. Interestingly, a portion of the CkTrk1 molecules were localized to the vacuolar membrane. The presence of CkTrk2 had no evident phenotype, due to the fact that this protein was not correctly targeted to the S. cerevisiae plasma membrane. Thus, CkTrk2 is the first studied yeast Trk protein to date that was not properly recognized and targeted to the plasma membrane upon heterologous expression in S. cerevisiae.

• Klíčová slova
• Candida, Trk proteins, cation homeostasis, potassium uptake, yeast K+ transporters,
• MeSH
• Candida klasifikace   genetika   růst a vývoj   metabolismus   MeSH
• draslík metabolismus   MeSH
• fungální proteiny genetika   metabolismus   MeSH
• fylogeneze MeSH
• genetická variace MeSH
• genom fungální genetika   MeSH
• iontový transport MeSH
• proteiny přenášející kationty genetika   metabolismus   MeSH
• rekombinantní proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae klasifikace   genetika   růst a vývoj   metabolismus   MeSH
• Saccharomycetales klasifikace   genetika   MeSH
• testy genetické komplementace MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• draslík MeSH
• fungální proteiny MeSH
• proteiny přenášející kationty MeSH
• rekombinantní proteiny MeSH

The functional expression of the mouse Kir2.1 potassium channel in yeast cells lacking transport systems for potassium and sodium efflux (ena1-4delta nha1delta) resulted in increased cell sensitivity to high external concentrations of potassium. The phenotype depended on the level of Kir2.1 expression and on the external pH. The activity of Kir2.1p in the yeast cells was almost negligible at pH 3.0 and the highest at pH 7.0. Kir2.1p was permeable for both potassium and rubidium cations, but neither sodium nor lithium were transported via the channel. Measurements of the cation contents in cells confirmed the higher concentration of potassium in cells with Kir2.1p. Specific inhibition of the mKir2.1 channel activity by Ba2+ cations was observed. The use of a mutant strain lacking both potassium efflux and uptake transporters (ena1-4delta nha1delta trk1delta trk2delta) enabled the monitoring of channel activity on two levels--the provision of the necessary amount of intracellular K+ in media with low potassium concentrations, and simultaneously, the channel's contribution to cell potassium sensitivity in the presence of high external K+. This combination of mutations proved to be a new, sensitive and practical tool for characterizing the properties of heterologously expressed transporters mediating both the efflux and influx of alkali-metal-cations.

• MeSH
• alkalické kovy metabolismus   MeSH
• baryum farmakologie   MeSH
• draslík metabolismus   MeSH
• draslíkové kanály dovnitř usměrňující antagonisté a inhibitory   biosyntéza   metabolismus   MeSH
• fenotyp MeSH
• iontový transport MeSH
• Saccharomyces cerevisiae růst a vývoj   metabolismus   MeSH
• transformace genetická MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• alkalické kovy MeSH
• baryum MeSH
• draslík MeSH
• draslíkové kanály dovnitř usměrňující MeSH
• Kir2.1 channel MeSH Prohlížeč

• MeSH
• draslík metabolismus   MeSH
• fungální proteiny genetika   fyziologie   MeSH
• iontový transport účinky léků   MeSH
• lithium farmakologie   MeSH
• membránové proteiny genetika   fyziologie   MeSH
• mutace MeSH
• proteiny přenášející kationty * MeSH
• Saccharomyces cerevisiae - proteiny * MeSH
• Saccharomyces cerevisiae účinky léků   metabolismus   MeSH
• sodík farmakologie   MeSH
• transportní proteiny genetika   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• draslík MeSH
• fungální proteiny MeSH
• lithium MeSH
• membránové proteiny MeSH
• proteiny přenášející kationty * MeSH
• Saccharomyces cerevisiae - proteiny * MeSH
• sodík MeSH
• transportní proteiny MeSH
• TRK1 protein, S cerevisiae MeSH Prohlížeč
• TRK2 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

Many mammalian species including human are immature at birth and undergo major developmental changes during suckling and weaning period. This problem is also conspicuous for the gastrointestinal tract that undergoes abrupt transitions coinciding with birth and weaning. This review deals with the maturation of ion transport functions in colon, the intestinal segment that plays an important role in sodium and potassium absorption and secretion. The purpose of the present review is to summarize the mechanism of sodium and potassium transport pathways and show how these transport processes change postnatally and how hormones, particularly corticosteroids, modify the pattern of development. Finally we describe some of the ways, how to analyze corticosteroid metabolism in target tissue.

• MeSH
• elektroforéza kapilární MeSH
• glukokortikoidy metabolismus   MeSH
• hormony kůry nadledvin metabolismus   fyziologie   MeSH
• iontový transport MeSH
• kolon růst a vývoj   metabolismus   MeSH
• lidé MeSH
• sodíko-draslíková ATPasa fyziologie   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• glukokortikoidy MeSH
• hormony kůry nadledvin MeSH
• sodíko-draslíková ATPasa MeSH

Wild-type cells of Candida albicans, the most common human fungal pathogen, are able to grow at very low micromolar concentrations of potassium in the external milieu. One of the reasons behind that behaviour is the existence of three different types of K+ transporters in their plasma membrane: Trk1, Acu1 and Hak1. This work shows that the transporters are very differently regulated at the transcriptional level upon exposure to saline stress, pH alterations or K+ starvation. We propose that different transporters take the lead in the diverse environmental conditions, Trk1 being the "house-keeping" one, and Acu1/Hak1 dominating upon K+ limiting conditions. Heterologous expression of the genes coding for the three transporters in a Saccharomyces cerevisiae strain lacking its endogenous potassium transporters showed that all of them mediated cation transport but with very different efficiencies. Moreover, expression of the transporters in S. cerevisiae also affected other physiological characteristics such as sodium and lithium tolerance, membrane potential or intracellular pH, being, in general, CaTrk1 the most effective in keeping these parameters close to the usual wild-type physiological levels.

• Klíčová slova
• Acu1, Candida albicans, Hak1, Heterologous expression, Potassium transport, Trk1,
• MeSH
• buněčná membrána genetika   metabolismus   MeSH
• Candida albicans genetika   metabolismus   MeSH
• draslík metabolismus   MeSH
• fungální proteiny genetika   metabolismus   MeSH
• lidé MeSH
• proteiny přenášející kationty genetika   metabolismus   MeSH
• Saccharomyces cerevisiae genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• draslík MeSH
• fungální proteiny MeSH
• proteiny přenášející kationty MeSH
• Trk1 protein, Candida albicans MeSH Prohlížeč

Yeasts usually have one or two high-affinity potassium transporters. Two complete and one interrupted gene encoding three types of putative potassium uptake system exist in Candida albicans SC5314. As high intracellular potassium is essential for many yeast cell functions, the existence of three transporters with differing transport mechanisms (Trk uniporter, Hak cation-proton symporter, Acu ATPase) may help pathogenic C. albicans cells to acquire the necessary potassium in various organs and tissues of the host. When expressed in Saccharomyces cerevisiae lacking their own potassium uptake systems, all three putative transporters were able to provide cells with the ability to grow with low amounts of potassium over a broad range of external pH. Only CaTrk1 was properly recognized and secreted to the plasma membrane. Nevertheless, even the small number of CaHak1 and mainly CaAcu1 molecules which reached the plasma membrane resulted in an improved growth of cells in low potassium concentrations, suggesting a high affinity and capacity of the transporters. A single-point mutation restored the complete CaACU1 gene, and the resulting protein not only provided cells with the necessary potassium but also improved their tolerance to toxic lithium. In contrast to its known homologues, CaAcu1 did not seem to transport sodium.

• Klíčová slova
• Acu1 ATPase, Candida, Hak1 transporter, Trk1 transporter, cation homeostasis, potassium uptake,
• MeSH
• Candida albicans genetika   metabolismus   MeSH
• draslík metabolismus   MeSH
• koncentrace vodíkových iontů MeSH
• kultivační média chemie   MeSH
• membránové transportní proteiny genetika   metabolismus   MeSH
• proteiny přenášející kationty nedostatek   MeSH
• rekombinantní proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny MeSH
• Saccharomyces cerevisiae genetika   růst a vývoj   metabolismus   MeSH
• testy genetické komplementace MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• draslík MeSH
• kultivační média MeSH
• membránové transportní proteiny MeSH
• proteiny přenášející kationty MeSH
• rekombinantní proteiny MeSH
• Saccharomyces cerevisiae - proteiny MeSH
• Trk1 protein, Candida albicans MeSH Prohlížeč
• TRK1 protein, S cerevisiae MeSH Prohlížeč
• TRK2 protein, S cerevisiae MeSH Prohlížeč

The absence of high-affinity potassium uptake in Candida glabrata, the consequence of the deletion of the TRK1 gene encoding the sole potassium-specific transporter, has a pleiotropic effect. Here, we show that in addition to changes in basic physiological parameters (e.g., membrane potential and intracellular pH) and decreased tolerance to various cell stresses, the loss of high affinity potassium uptake also alters cell-surface properties, such as an increased hydrophobicity and adherence capacity. The loss of an efficient potassium uptake system results in diminished virulence as assessed by two insect host models, Drosophila melanogaster and Galleria mellonella, and experiments with macrophages. Macrophages kill trk1Δ cells more effectively than wild type cells. Consistently, macrophages accrue less damage when co-cultured with trk1Δ mutant cells compared to wild-type cells. We further show that low levels of potassium in the environment increase the adherence of C. glabrata cells to polystyrene and the propensity of C. glabrata cells to form biofilms.

• MeSH
• biofilmy růst a vývoj   MeSH
• buněčná adheze fyziologie   MeSH
• buněčná membrána metabolismus   MeSH
• buněčné linie MeSH
• Candida glabrata genetika   metabolismus   patogenita   MeSH
• draslík metabolismus   MeSH
• draslíko-vodíkové antiportéry genetika   MeSH
• Drosophila melanogaster mikrobiologie   MeSH
• hydrofobní a hydrofilní interakce MeSH
• iontový transport MeSH
• lidé MeSH
• makrofágy imunologie   MeSH
• membránové potenciály fyziologie   MeSH
• můry mikrobiologie   MeSH
• povrchové vlastnosti MeSH
• proteiny přenášející kationty genetika   MeSH
• regulace genové exprese u hub genetika   MeSH
• THP-1 buňky MeSH
• virulence genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• draslík MeSH
• draslíko-vodíkové antiportéry MeSH
• proteiny přenášející kationty MeSH
• Trk1 protein, Candida albicans MeSH Prohlížeč