The Saccharomyces cerevisiae general amino acid permease Gap1 (ScGap1) not only mediates the uptake of most amino acids but also functions as a receptor for the activation of protein kinase A (PKA). Fungal pathogens can colonize different niches in the host, each containing various levels of different amino acids and sugars. The Candida albicans genome contains six genes homologous to the S. cerevisiae GAP1. The expression of these six genes in S. cerevisiae showed that the products of all six C. albicans genes differ in their transport capacities. C. albicans Gap2 (CaGap2) is the true orthologue of ScGap1 as it transports all tested amino acids. The other CaGap proteins have narrower substrate specificities though CaGap1 and CaGap6 transport several structurally unrelated amino acids. CaGap1, CaGap2, and CaGap6 also function as sensors. Upon detecting some amino acids, e.g., methionine, they are involved in a rapid activation of trehalase, a downstream target of PKA. Our data show that CaGAP genes can be functionally expressed in S. cerevisiae and that CaGap permeases communicate to the intracellular signal transduction pathway similarly to ScGap1.

• MeSH
• Candida albicans genetika   metabolismus   MeSH
• geny hub MeSH
• molekulární sekvence - údaje MeSH
• proteinkinasy závislé na cyklickém AMP metabolismus   MeSH
• regulace genové exprese u hub genetika   MeSH
• Saccharomyces cerevisiae - proteiny genetika   metabolismus   fyziologie   MeSH
• Saccharomyces cerevisiae genetika   MeSH
• sekvence nukleotidů MeSH
• transportní systémy aminokyselin genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• GAP1 protein, S cerevisiae MeSH Prohlížeč
• proteinkinasy závislé na cyklickém AMP MeSH
• Saccharomyces cerevisiae - proteiny MeSH
• transportní systémy aminokyselin MeSH

The virulence of Candida species depends on many environmental conditions, including extracellular pH and concentration of alkali metal cations. Tests of the tolerance/sensitivity of four pathogenic Candida species (C. albicans, C. dubliniensis, C. glabrata, and C. parapsilosis) to alkali metal cations under various growth conditions revealed significant differences among these species. Though all of them can be classified as rather osmotolerant yeast species, they exhibit different levels of tolerance to different salts. C. parapsilosis and C. albicans are the most salt-tolerant in general; C. dubliniensis is the least tolerant on rich YPD media and C. glabrata on acidic (pH 3.5) minimal YNB medium. C. dubliniensis is relatively salt-sensitive in spite of its ability to maintain as high intracellular K(+)/Na(+) ratio as its highly salt-tolerant relative C. albicans. On the other hand, C. parapsilosis can grow in the presence of very high external NaCl concentrations in spite of its high intracellular Na(+) concentrations (and thus lower K(+)/Na(+) ratio) and thus resembles salt-tolerant (halophilic) Debaryomyces hansenii.

• MeSH
• Candida albicans patogenita   fyziologie   MeSH
• Candida glabrata patogenita   fyziologie   MeSH
• Candida metabolismus   patogenita   fyziologie   MeSH
• chlorid draselný analýza   farmakologie   MeSH
• chlorid lithný analýza   farmakologie   MeSH
• chlorid sodný analýza   farmakologie   MeSH
• druhová specificita MeSH
• soli MeSH
• tolerance k soli fyziologie   MeSH
• virulence MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• chlorid draselný MeSH
• chlorid lithný MeSH
• chlorid sodný MeSH
• soli MeSH

The transport activity and substrate specificity of two chimeras consisting of S. cerevisiae Nha1p's N-terminal regions (either first 125 or 184 AA) and the rest of the C. glabrata Cnh1p (up to the total protein length of 946 AA) were compared with those of the two native antiporters. Both chimeric transporters were functional upon expression in S. cerevisiae cells, their presence improved the ability of cells to grow in the presence of high external concentration of K(+), Na(+) or Rb(+) (as chlorides), but not in the presence of the smallest cation (Li(+)). Cation efflux confirmed the ability of chimeras to export cations and showed their significantly reduced transport capacity compared to the wild-type proteins. Despite the very high level of primary sequence identity (87 %) between the S. cerevisiae and C. glabrata plasma-membrane Na(+)/H(+) antiporters, various parts of these proteins are not exchangeable without affecting the antiporter's transport capacity.

• MeSH
• Candida glabrata účinky léků   genetika   růst a vývoj   metabolismus   MeSH
• chlorid draselný farmakologie   MeSH
• chlorid sodný farmakologie   MeSH
• fungální proteiny chemie   genetika   metabolismus   MeSH
• molekulární sekvence - údaje MeSH
• Na(+)-H(+) antiport chemie   genetika   metabolismus   MeSH
• proteiny přenášející kationty chemie   genetika   metabolismus   MeSH
• rekombinantní fúzní proteiny chemie   genetika   metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny chemie   genetika   metabolismus   MeSH
• Saccharomyces cerevisiae účinky léků   genetika   růst a vývoj   metabolismus   MeSH
• sekvence aminokyselin MeSH
• sekvenční analýza DNA MeSH
• sekvenční seřazení MeSH
• tolerance k soli * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chlorid draselný MeSH
• chlorid sodný MeSH
• CNH1 protein, Candida albicans MeSH Prohlížeč
• fungální proteiny MeSH
• Na(+)-H(+) antiport MeSH
• NHA1 protein, S cerevisiae MeSH Prohlížeč
• proteiny přenášející kationty MeSH
• rekombinantní fúzní proteiny MeSH
• Saccharomyces cerevisiae - proteiny MeSH

BACKGROUND: The virulence of Candida species depends on many environmental conditions. Extracellular pH and concentration of alkali metal cations belong among important factors. Nevertheless, the contribution of transporters mediating the exchange of alkali metal cations for protons across the plasma membrane to the cell salt tolerance and other physiological properties of various Candida species has not been studied so far. RESULTS: The tolerance/sensitivity of four pathogenic Candida species to alkali metal cations was tested and the role of one of the cation transporters in that tolerance (presumed to be the plasma-membrane Na+/H+ antiporter) was studied. The genes encoding these antiporters in the most and least salt sensitive species, C. dubliniensis and C. parapsilosis respectively, were identified, cloned and functionally expressed in the plasma membranes of Saccharomyces cerevisiae cells lacking their own cation exporters. Both CpCnh1 and CdCnh1 antiporters had broad substrate specificity and transported Na+, K+, Li+, and Rb+. Their activity in S. cerevisiae cells differed; CpCnh1p provided cells with a much higher salt tolerance than the CdCnh1 antiporter. The observed difference in activity was confirmed by direct measurements of sodium and potassium efflux mediated by these antiporters. CONCLUSION: We have cloned two genes encoding putative Na+/H+ antiporters in C. parapsilosis and C. dubliniensis, and characterized the transport properties of encoded proteins. Our results show that the activity of plasma-membrane Na+/H+ antiporters is one of the factors determining the tolerance of pathogenic Candida species to high external concentrations of alkali metal cations.

• MeSH
• alkalické kovy metabolismus   MeSH
• Candida genetika   růst a vývoj   metabolismus   patogenita   MeSH
• draslík metabolismus   MeSH
• fluorescenční mikroskopie MeSH
• fungální proteiny genetika   metabolismus   MeSH
• kationty metabolismus   MeSH
• lithium metabolismus   MeSH
• membránové proteiny genetika   metabolismus   MeSH
• molekulární sekvence - údaje MeSH
• Na(+)-H(+) antiport genetika   metabolismus   MeSH
• proteiny přenášející kationty genetika   metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae genetika   růst a vývoj   metabolismus   MeSH
• sekundární struktura proteinů MeSH
• sekvence nukleotidů MeSH
• soli metabolismus   MeSH
• substrátová specifita MeSH
• superoxiddismutasa 1 MeSH
• superoxiddismutasa metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• alkalické kovy MeSH
• CNH1 protein, Candida albicans MeSH Prohlížeč
• draslík MeSH
• fungální proteiny MeSH
• kationty MeSH
• lithium MeSH
• membránové proteiny MeSH
• Na(+)-H(+) antiport MeSH
• NHA1 protein, S cerevisiae MeSH Prohlížeč
• proteiny přenášející kationty MeSH
• Saccharomyces cerevisiae - proteiny MeSH
• soli MeSH
• superoxiddismutasa 1 MeSH
• superoxiddismutasa MeSH